Mesh / AR-VR

• 3DViewStation

• CADfix
• 3DViewStation
• SimLab

In an industrial environment characterized by diverse design tools, 3D data interoperability remains a major challenge for companies. The Universal Scene Description (USD) formats and its compact version USDZ are emerging as promising solutions to standardize technical data exchanges while offering new possibilities for visualization and collaboration. Initially developed for the entertainment industry, these formats are now finding their place in engineering and industrial design processes, bringing with them unique capabilities to solve persistent problems of data translation between heterogeneous systems.

Table of contents

• Fundamentals of the USD/USDZ format: origins and technical characteristics
• Advantages of USD/USDZ for professional CAD interoperability
• Industrial applications and use cases of USD/USDZ format
• Software solutions for conversion and preparation of USD/USDZ files
• Implementation strategies and best practices for USD/USDZ adoption

Fundamentals of the USD/USDZ format: origins and technical characteristics

Universal Scene Description (USD) represents a major innovation in the field of 3D data exchange. Initially developed by Pixar Animation Studios to address complex film production needs, this format quickly established itself as a reference for complete and coherent description of 3D scenes.

Origins and development

USD was designed by Pixar to solve specific collaboration problems on animation projects involving countless interconnected 3D elements. The first public version of USD was made available open source in 2016, marking the beginning of its adoption beyond the entertainment sector. USDZ, an extension of the USD format, was developed in collaboration with Apple to facilitate augmented reality experiences on iOS devices and today constitutes a de facto standard for mobile AR applications.

The USD format is distinguished by its advanced technical architecture:

• Architecture based on composition layers allowing non-destructive modifications
• Support for collaborative work via reference mechanisms and variants
• Possible representation in ASCII (.usda) or binary (.usdc) form for different use cases
• Extensible metadata system for storing custom technical information

The USDZ format, meanwhile, is an uncompressed archive containing a main USD file and all its dependencies (textures, materials, etc.) in a single standalone package, facilitating deployment on mobile and web platforms.

Types of data supported

USD/USDZ supports a wide range of 3D data essential for engineering applications:

• Geometry: polygonal meshes, NURBS surfaces and subdivisions
• Object hierarchy and complex assembly structures
• Physically based materials (PBR) with high-resolution textures
• Animations and parametric transformations
• Advanced cameras and lighting parameters
• Technical metadata and custom properties for PLM

This richness of representation allows preserving design intent and critical information during conversions between native CAD formats and USD.

Fundamental technical advantages

The technical characteristics that distinguish USD/USDZ include:

• Optimized performance for loading and manipulating complex scenes
• Extensible architecture allowing the addition of new schemas and functionalities
• Ability to represent complex object hierarchies with thousands of components
• Native support for levels of detail (LOD) for adaptive visualization
• Real-time composition allowing non-destructive data modification

These technical attributes make USD/USDZ a solution particularly suited to interoperability challenges in modern multi-CAD environments where preserving CAD data quality is essential.

Advantages of USD/USDZ for professional CAD interoperability

The adoption of USD and USDZ formats in professional CAD workflows addresses several persistent interoperability challenges while bringing new essential capabilities for modern companies.

Collaborative work management

One of the major assets of USD lies in its fundamentally collaborative design:

• Ability to work simultaneously on different parts of the same model
• Reference system allowing automatic update of modifications
• Variant mechanism to explore different design options

These features promote smooth collaboration between design, engineering, simulation, and marketing teams, thereby reducing development cycles and improving technical data exchange.

Support for modern definitions

USD/USDZ perfectly aligns with current industry trends:

• Native support for PBR (Physically Based Rendering) materials for realistic rendering
• Compatibility with advanced lighting techniques (IBL, HDR)

These capabilities enable creating visually faithful and functionally complete digital twins that can be shared between different departments and external partners.

Comparison with other exchange standards

This comparison shows that USD/USDZ effectively complements the ecosystem of standardized exchange formats with unique capabilities particularly adapted to modern visualization and immersive experience needs.

Industrial applications and use cases of USD/USDZ format

The USD and USDZ formats find concrete applications in many industrial sectors, addressing specific needs while bringing new possibilities for innovation.

Augmented reality and advanced visualization

One of the most visible use cases for USDZ concerns augmented reality, particularly in the Apple ecosystem:

• Immediate visualization of products in real context on iOS devices
• Creation of interactive experiences for technical training
• Virtual prototyping allowing aesthetic and ergonomic evaluation
• Advanced commercial presentations with manipulable 3D models

An industrial equipment manufacturer can thus allow its customers to visualize a complex system directly in their work environment before purchase, facilitating decision-making and reducing the risk of inadequacy.

Integration into existing CAD workflows

The adoption of USD/USDZ integrates naturally into existing design processes:

• Bridge between traditional CAD systems and modern visualization platforms
• Data exchange between departments using different specialized software
• Quick visual validation of concepts without requiring expensive CAD licenses
• Optimized preparation for 3D printing and manufacturing

These use cases demonstrate how USD can serve as a central pivot format in a multi-CAD ecosystem, facilitating exchanges while preserving data integrity and improving 3D data conversion.

Transition between traditional and modern environments

USD facilitates the digital transition of companies:

• Gradual transition from proprietary formats to open standards
• Adaptation to growing needs for mobility and remote data access
• Integration of cloud-based processes for international collaboration
• Compatibility with new agile development methodologies

This flexibility allows organizations to evolve at their own pace while preserving their investments in existing systems and improving global CAD interoperability.

Technical data archiving and sharing

The characteristics of USD make it an excellent candidate for long-term archiving:

• Open and well-documented format reducing obsolescence risks
• Preservation of visual and geometric richness in a single format
• Independence from proprietary software
• Structure allowing validation and integrity of archived data

For industries subject to strict regulatory requirements like aerospace or medical, this reliable archiving capability represents a significant advantage for preserving technical data over the long term.

Software solutions for conversion and preparation of USD/USDZ files

Effective adoption of USD/USDZ formats requires specialized tools for conversion, visualization, and data reuse. CAD Interop distributes three complementary solutions addressing these specific needs.

SimLab: creating immersive experiences from USDZ models

SimLab positions itself as a powerful tool for transforming CAD data into immersive experiences in USDZ format:

• Direct import from main native CAD formats (CATIA, NX, SolidWorks)
• Accurate conversion preserving hierarchy and assembly structure
• Advanced tools for applying PBR materials and textures
• Creation of animations and interactions to enrich the user experience
• Optimized export to USDZ for immediate use in augmented reality

SimLab particularly excels in preparing models for commercial presentations and interactive catalogs, allowing customers to virtually explore products with an unprecedented level of detail.

3DViewStation: visualization, analysis and conversion to USDZ

3DViewStation offers a complete set of tools for working with USD/USDZ formats:

• High-performance visualization of complex CAD models with high-quality rendering
• Geometric analysis functionalities (measurements, sections, comparisons)
• Bidirectional conversion between native CAD formats and USD/USDZ
• Annotation and technical documentation tools
• Automation options for batch processing of conversions

The capabilities of 3DViewStation make it an ideal choice for technical teams requiring quick access to 3D data without the original CAD software. Its performance with large assemblies allows lightweight data visualization even on standard hardware configurations.

CADfix VIZ: repair and simplification of USDZ data

CADfix VIZ focuses on quality and optimization of 3D models:

• Automatic detection and repair of geometric errors
• Intelligent simplification of models for different levels of detail
• Geometric healing to ensure B-rep surface integrity
• Mesh optimization for augmented reality applications
• Data preparation for resource-limited environments

These functionalities are essential for preparing complex CAD models for use in mobile or web contexts, where performance constraints are particularly important and where geometric validation becomes critical.

Integration of solutions in PLM environments

The three solutions offered by CAD Interop integrate harmoniously into existing PLM ecosystems:

• Programming interfaces (API) for process automation
• Support for metadata structures compatible with common PLM systems
• Integration possibilities with document management systems
• Traceability of conversions and modifications for regulatory compliance

This integration allows establishing coherent workflows where the conversion and optimization of USD/USDZ data become a natural step in the product lifecycle and technical data exchange.

Implementation strategies and best practices for USD/USDZ adoption

Successful integration of USD/USDZ formats in an organization requires a methodical and progressive approach. Here are the recommended strategies and best practices to maximize the benefits of this adoption.

Evaluation and preparation methodology

Before implementing USD/USDZ in your production environment, a systematic evaluation phase is essential:

• Audit of CAD formats and software currently used in the organization
• Identification of priority use cases for USD/USDZ adoption
• Assessment of needs in terms of visual and geometric fidelity
• Analysis of integration requirements with existing systems
• Pilot tests on representative projects to evaluate conversion quality

This preparatory phase allows establishing realistic expectations and targeting areas where USD/USDZ will bring the greatest added value for CAD interoperability and technical data simplification.

Geometric quality validation

Data quality is paramount in any CAD interoperability process:

• Establishment of validation criteria specific to your industry
• Implementation of systematic post-conversion verification processes
• Use of tools like CADfix VIZ to detect and correct errors
• Metric comparison between original and converted models
• Documentation of results to ensure traceability and continuous improvement

These practices ensure that the transition to USD/USDZ does not compromise the integrity of essential technical data and maintains CAD data quality throughout the process.

Progressive migration plan

The adoption of USD/USDZ benefits from being deployed in phases:

• Start with non-critical projects to develop internal expertise
• Establish parallel processes before replacing existing workflows
• Gradually train teams on new methodologies
• Progressively expand the scope of use as confidence increases
• Document and share successes to promote organizational buy-in

This measured approach minimizes risks while allowing the organization to absorb practice changes organically and optimize its technical data exchange processes.

Evolution perspectives and preparation for future innovations

USD/USDZ continues to evolve, offering new opportunities:

• Monitoring developments of the USD specification by Pixar and its partners
• Watching the growing integration in AR/VR ecosystems
• Anticipating future needs in terms of digital twins
• Preparing for the expansion of use cases in the industrial metaverse
• Participation in technical communities to influence future developments

This forward-looking vision helps ensure that investment in USD/USDZ is part of a sustainable and evolving digital strategy for long-term CAD interoperability.

How to choose the USD/USDZ interoperability solution adapted to your needs?

The choice of appropriate tools depends on several factors specific to your usage context:

• For marketing and commercial teams looking to create engaging customer experiences, SimLab offers the best balance between ease of use and visual quality
• Engineering and technical services departments requiring precise analysis will benefit more from 3DViewStation for CAD model visualization and interoperability
• Projects involving complex or legacy CAD models will significantly benefit from the repair and data simplification capabilities of CADfix VIZ

The combined use of these solutions allows covering the entire spectrum of USD/USDZ interoperability needs in a complete multi-CAD industrial environment.

Conclusion

The adoption of USD and USDZ formats represents a strategic advance for organizations facing persistent CAD interoperability challenges. These formats not only bring solutions to traditional conversion problems but also open new possibilities in terms of immersive visualization, collaboration, and technical communication.

By integrating the specialized solutions distributed by CAD Interop – SimLab for experience creation, 3DViewStation for visualization and conversion, and CADfix VIZ for optimization – companies can establish a robust and sustainable interoperability ecosystem. This holistic approach maximizes the value of existing CAD data while preparing the organization for future developments in digital design.

In an industrial context where accelerating development cycles and integrating immersive technologies are becoming differentiating factors, mastering the interoperability of USD/USDZ formats constitutes a strategic investment to maintain your operational agility and optimize your technical data exchange processes.

• SimLab

Table of Contents

1. History and Evolution of MODO
2. Architecture and Geometric Engine of MODO
3. Native Formats and Exchange Capabilities
4. Table of Compatible Formats
5. SimLab Composer: Create Immersive Experiences with MODO
6. Best Practices for Interoperability with MODO
7. How to Optimize Data Exchange Between MODO and CAD Systems

CAD data interoperability is a major challenge for companies using multiple software solutions in their design chain. MODO, a powerful 3D modeling, texturing, and rendering software, is part of this complex ecosystem where the fluidity of technical data exchange is essential. This article explores MODO's interoperability capabilities, its exchange formats, and solutions to optimize 3D data conversion between MODO and other CAD systems.

History and Evolution of MODO

MODO was initially developed by Luxology LLC in 2004, founded by key developers who left NewTek, the company behind LightWave 3D. This genesis explains certain similarities between the two software packages, particularly in terms of file formats. In 2012, The Foundry (now simply called Foundry) acquired Luxology, integrating MODO into its portfolio of creative solutions.

Since its creation, MODO has distinguished itself through several innovative features:

• Intuitive interface oriented toward productivity
• Advanced polygonal modeling and subdivision surface tools
• Integrated high-performance rendering system
• Texturing and animation capabilities

MODO's philosophy has always been to offer a flexible and powerful 3D modeling environment, particularly appreciated in the design, video game, and film industries. Its growing adoption has naturally raised questions of interoperability with traditional CAD systems, which are often based on a parametric rather than polygonal approach.

Architecture and Geometric Engine of MODO

MODO is distinguished by its approach centered on polygonal modeling and subdivision surfaces, unlike traditional CAD systems that favor parametric modeling and NURBS surfaces (Non-Uniform Rational B-Splines). This fundamental difference constitutes both a creative strength and an interoperability challenge.

Characteristics of MODO's geometric engine:

• Direct polygonal modeling with intuitive mesh manipulation
• Advanced subdivision surface system for obtaining smooth surfaces
• Powerful topology creation and editing tools
• Free manipulation of geometries without parametric constraints
• Support for "non-conforming" geometries that can pose problems when exporting to other systems

This architecture focused on creative freedom allows designers to quickly produce complex forms, but requires specific conversion processes for integration into traditional CAD workflows. The transition between B-rep (Boundary Representation) representations of CAD systems and MODO meshes requires specialized conversion techniques to preserve data integrity.

Native Formats and Exchange Capabilities of MODO

MODO uses several proprietary file formats to store its data, while offering numerous import and export options to facilitate interoperability with other software solutions.

MODO native formats:

• .LXO: MODO's main format that stores all the information of the 3D model, including geometry, textures, materials, and animations
• .LWO: Format inherited from LightWave 3D, maintained for compatibility
• .LXE: Preconfigured environment format
• .LXL: Single-layer mesh preset format

In addition to these proprietary formats, MODO offers a wide range of import/export options that make it a flexible tool in a diverse digital production chain. The software notably supports standard CAD formats such as STEP, IGES, and SAT, facilitating data exchange with engineering software.

For visualization and animation needs, MODO also supports common industry formats such as FBX, OBJ, and Alembic, the latter being particularly important for exchanging animation and simulation data with other DCC (Digital Content Creation) applications.

Table of Compatible Formats with MODO

The table below presents the main formats supported by MODO for import and export, organized by categories:

This extended compatibility positions MODO as a versatile tool in multi-CAD enterprise workflows, facilitating the exchange of technical data between different design platforms.

SimLab Composer: Create Immersive Experiences with MODO

CAD Interop distributes SimLab Composer, a powerful solution that integrates perfectly with MODO to extend its 3D data visualization and communication capabilities.

Key features of SimLab Composer integration with MODO:

• Free integration plugin that creates an active link between MODO and SimLab Composer
• Bidirectional data synchronization without the need for repetitive import/export
• Preservation of modifications made in SimLab while updating design changes in MODO

SimLab Composer's functionalities perfectly complement MODO's modeling capabilities by adding advanced visualization and communication options:

1. Creation of VR experiences: Rapid transformation of MODO models into interactive virtual reality experiences
2. Realistic and fast rendering: Production of images, videos, animations, and 360° renders with a high-performance progressive rendering engine
3. 3D PDF documents: Integration of 3D models into PDF documents for universal sharing
4. Texture Baking: Application and baking of textures for realistic rendering, particularly useful when sharing in 3D PDF and WebGL

This interoperability solution is particularly aimed at users who wish to maintain MODO's creative power while benefiting from advanced 3D data presentation and communication options in a professional context.

Best Practices for Interoperability with MODO

Effective use of MODO in a multi-CAD environment requires the adoption of certain best practices to ensure the quality of data exchanges. Here are recommendations based on user experience and specialized forums:

Geometric validation before export:

• Regularly use the "Mesh Cleanup" tool to identify and correct non-conforming geometries
• Assign a keyboard shortcut to this tool to facilitate its frequent use9
• Be attentive to "illegal" geometries that MODO allows you to create but which can cause problems when exporting to other systems

Adapting to tool differences:

• Some functions have the same name but work differently between MODO and other software like 3ds Max
• For example, the "Inset" tool in MODO works differently from its equivalent in Max, and requires alternative approaches
• Similarly for extrusion, which requires specific techniques to reproduce the behaviors available in other software

Managing units and scales:

• Take into account that MODO uses the meter as its default unit, while other applications like Maya, Houdini, or Nuke use centimeters
• Adjust the "Scale" parameter in the import/export preferences to compensate for these differences during exchanges
• Systematically check dimensions after import/export to ensure scale consistency

These practices help avoid common problems during data exchange and contribute to better integration of MODO in a multi-software production environment.

How to Optimize Data Exchange Between MODO and CAD Systems

Optimizing data exchange between MODO and traditional CAD systems relies on understanding the fundamental differences between modeling approaches and using appropriate tools to facilitate 3D data conversion.

Understanding representation differences:

• MODO primarily uses polygonal meshes and subdivision surfaces
• CAD systems generally use parametric models based on construction histories
• Converting between these two paradigms requires specific data translation processes

Model preparation strategies for export:

• Simplify complex geometries while preserving design intent
• Check the validity of polygon normals and correct them if necessary
• Clean meshes to eliminate non-manifold geometries or other defects
• Organize models hierarchically in a logical manner before export

Choosing the optimal exchange format:

• For engineering and manufacturing: prefer STEP, IGES, or native formats via dedicated plugins
• For visualization and presentation: FBX, OBJ, or 3D PDF via SimLab
• For animation and effects: Alembic to preserve kinematic and simulation data
• For long-term archiving: combination of standard formats (STEP) and lightweight formats for visualization

These solutions enable efficient integration of MODO into a multi-CAD enterprise ecosystem, facilitating 3D data conversion between different systems while preserving model integrity and adding advanced visualization and communication capabilities. The combination of these specialized tools with interoperability best practices allows you to fully leverage MODO's creative capabilities while ensuring seamless integration with traditional engineering and manufacturing processes.

• SimLab

Table of Contents

1. History and Evolution of OpenSceneGraph
2. Technical Characteristics and Features
3. File Formats and Compatibility
4. Interoperability with CAD Systems
5. Comparison with Other 3D Visualization Formats
6. CAD Interop Solutions for OpenSceneGraph
7. Best Practices for OSG File Exchange
8. Practical Applications and Use Cases

OpenSceneGraph represents a robust solution for the interoperability of technical data from CAD systems to visualization and virtual reality applications. This open-source 3D engine offers a powerful platform for transforming complex models into interactive visualizations accessible on various platforms.

OpenSceneGraph is a 3D engine programmed entirely in C++ and built around OpenGL, which gives it exceptional compatibility with many operating systems, including IRIX, Linux, FreeBSD, Mac OS X, and Windows. This versatility makes it a preferred choice for projects requiring multi-platform interoperability of CAD data.

Since its inception, OSG has established itself as a reference solution for visualizing complex 3D models in various fields such as flight simulations, marine and spatial applications, scientific visualization, education, and even games. Its ability to handle complex 3D scenes while maintaining optimal performance explains its persistent popularity despite the emergence of new technologies.

History and Evolution of OpenSceneGraph

The OpenSceneGraph project was launched in 1998 by Don Burns, who subsequently created his own company while continuing to contribute to the project's development. A major turning point occurred in 1999 when Robert Osfield joined the team, initially working on porting components for Microsoft Windows.

In September 1999, OpenSceneGraph's source code was made public under the terms of the LGPL license, marking the beginning of its journey as an open-source project. Towards the end of that same year, Osfield took over the project's direction and undertook a major overhaul of the existing code, emphasizing modernization and the adoption of contemporary C++ standards and design patterns.

The project was professionalized in April 2001 when Robert Osfield founded OpenSceneGraph Professional Services, offering commercial support, consulting services, and training. The first official stable version (1.0) was released in 2005, followed by version 2.0 in 2007, which added support for multi-core and multi-GPU systems, several important NodeKits, and the use of the cross-platform CMake build system.

Since then, the project has experienced rapid growth with over 530 contributors to the current stable version. However, since 2019, OpenSceneGraph has entered a maintenance phase, with the main development effort now directed towards its successor, VulkanSceneGraph, based on Vulkan to take advantage of the latest hardware advances.

Today, the latest stable version of OpenSceneGraph is 3.6.5, released on January 31, 2020.

Technical Characteristics and Features

OpenSceneGraph offers a comprehensive set of features that make it particularly suitable for CAD data interoperability and advanced 3D visualization.

Architecture and Performance

OpenSceneGraph's architecture is based on a scene graph approach, representing 3D worlds as a graph of nodes grouped logically and spatially into subgraphs to optimize behavior and performance. This structure facilitates the hierarchical organization of complex data from CAD systems.

OpenSceneGraph offers high performance thanks to several optimization techniques:

• View frustum culling
• Occlusion culling
• Small feature culling
• Level of detail (LOD) nodes
• OpenGL state sorting
• Vertex arrays and vertex buffer objects
• OpenGL Shading Language (GLSL) support
• Display lists

Cross-Platform Support and Scalability

OpenSceneGraph's design allows for exceptional portability with minimal dependencies, essentially requiring only standard C++ and OpenGL. It runs on configurations ranging from portable devices to high-end multi-core and multi-GPU systems, as well as clusters.

The engine supports OpenGL from version 1.0 to 4.6, as well as OpenGL ES from version 1.1 to 3.2, allowing support for both older hardware and newer operating systems. Since version 3.0.0, OpenSceneGraph also supports application development for mobile platforms, including iOS and Android.

Threading Models and Memory Management

OpenSceneGraph incorporates a threading library called OpenThreads, which provides a lightweight object-oriented interface for C++ programmers. It is inspired by the Java thread API and POSIX Threads standards.

This multi-threaded design allows for executing multiple cull-draw traversal pairs on multiple processors linked to multiple graphics subsystems, thus maximizing performance on modern machines.

File Formats and Compatibility

OpenSceneGraph primarily uses its own native formats while offering broad compatibility with other industry standard formats.

Native Formats and Extensions

The *.osg file extension is used to store scenes created with OpenSceneGraph. These files contain information about 3D models, textures, lights, cameras, and scene configuration. OSG offers two main formats:

• ASCII Format (.osg) - Readable and editable text format
• Binary Format (.osgb) - More compact and faster to load

The .ive format, also native to OpenSceneGraph, is particularly fast to load, making it ideal for database storage and large databases.

Compatibility with Other Formats

OpenSceneGraph supports importing and exporting many file formats, including:

• COLLADA
• OpenFlight
• 3D Studio (.3ds)
• VRML
• Alias Wavefront (OBJ)
• Various 2D image formats (JPEG, PNG)
• Geospatial formats (GeoTIFF)

This extensive compatibility allows users to work with 3D models created in other software such as SketchUp, Maya, and Blender, and use them in their own OpenSceneGraph applications.

Geometric Support

According to the technical documentation, OpenSceneGraph primarily supports surface-type geometries, while other types such as points, lines, circles, or polygons are not directly supported. This specialization reflects its primary function of 3D visualization rather than complete CAD modeling.

Interoperability with CAD Systems

One of OpenSceneGraph's major strengths lies in its ability to serve as a bridge between complex CAD systems and lightweight visualization applications.

Data Conversion and Import

OpenSceneGraph provides a utility called osgconv that allows reading 3D databases, applying basic operations, and saving them as a single 3D database. This tool is particularly useful for:

• Reading standard 3D formats (OpenFlight, 3DS, OBJ, etc.)
• Converting these formats to native OSG formats (.osg or .ive)
• Optimizing the scene graph during loading to reduce size and improve performance

Texture Management

Texture conversion is a crucial aspect when transforming files between different formats to the OpenSceneGraph format. The .OSG format supports the "OutputTextureFiles" option that allows generating new external texture image files.

Important points regarding texture management:

• Texture files are generated using the original texture filename present in the scene
• The format used is determined by the filename extension
• Some combinations of formats and texture data may be incompatible (e.g., the .RGB format cannot store compressed texture data)
• Texture compression and decompression are performed by the OpenGL implementation and not by an OSG software algorithm

Comparison with Other 3D Visualization Formats

To better position OpenSceneGraph in the ecosystem of 3D visualization and VR/AR technologies, here is a comparison with three other major formats/technologies:

OpenSceneGraph distinguishes itself by its nature as a complete framework rather than a simple exchange format, offering an integrated solution for scientific visualization and simulation, but its evolution is now limited while other formats like glTF are experiencing more active development.

CAD Interop Solutions for OpenSceneGraph

CAD Interop distributes several software packages for preparing, visualizing, and converting OpenSceneGraph files. Among these solutions, SimLab particularly stands out for creating immersive experiences from OpenSceneGraph models.

SimLab VR Studio

SimLab VR Studio is a complete virtual reality experience creation workshop that allows transforming 3D models into interactive environments without requiring programming skills. Designed to simplify the 3D visualization process, it offers a suite of powerful and user-friendly tools.

Key features of SimLab VR Studio:

• Ease of use without coding skills
• Free license to test all features
• Rapid VR content creation
• Compatibility with a wide variety of VR systems and devices
• Support for over 30 3D file formats, facilitating interoperability
• Secure data processing with local conversion
• Import and modification of animations in real-time
• Libraries of pre-designed 3D models
• Dedicated tools for natural and realistic lighting
• VR interaction and logic with intuitive commands

Applications of SimLab VR Studio:

• Training in fields such as medicine, safety, and professional training
• Product demonstrations (furniture, cars, interior design)
• Immersive presentations for schools, universities, and businesses
• Entertainment, games, and virtual tourism

SimLab VR Viewer

Complementary to SimLab VR Studio, SimLab VR Viewer is a free, standalone, and multi-platform application that allows viewing 3D projects in virtual reality.

Main features of SimLab VR Viewer:

• Compatibility with almost all VR headsets on the market
• Dimension measurement tools facilitating interactions
• Annotation tools to enhance communication
• Various navigation modes (Walking, Flying, Mechanical)
• VR experience sharing functionality
• Available on iOS and Android
• Compatible with HTC Vive, Oculus PC, Oculus Quest, and PicoVR headsets

Integrated Cloud Services

The SimLab ecosystem also includes cloud services that allow:

• Secure storage and access to VR experiences
• Organization of experiences into catalogs
• Secure sharing of experiences or publication to the community
• Retrieval of modifications and notes added by recipients
• Hosting 3D models as online WebGL documents
• Synchronization between multiple devices via the SimLab Cloud account

Best Practices for OSG File Exchange

Based on information available in forums and technical documentation, here are some best practices for optimizing OpenSceneGraph file exchange:

Scene Graph Optimization

• Use osgconv to automatically optimize the scene graph during conversion, thus reducing file size and improving runtime performance
• For large databases, prefer the binary .ive format which is particularly fast to load

Texture Management

• Ensure that the destination directory specified for texture files exists before conversion
• Be aware of potential incompatibilities between certain formats and texture data types
• If you encounter corrupted texture issues, check your OpenGL driver compatibility, as texture compression/decompression is performed by the OpenGL implementation

Conversion Between Formats

• When converting formats like .IVE (with embedded textures) to .OSG (which doesn't embed them), use the "OutputTextureFiles" option to correctly generate external texture files
• Avoid converting compressed textures to formats that don't support compression (like .RGB)

Cross-Platform Compatibility

• Test your models on different platforms to ensure that texture paths and references are correctly resolved
• Use relative paths rather than absolute paths for texture file references

Why Consider Migrating to VulkanSceneGraph?

Since 2019, OpenSceneGraph has entered a maintenance phase, with the main development being redirected to VulkanSceneGraph. This evolution is explained by several factors:

• VulkanSceneGraph offers "unprecedented" performance and access to the latest hardware features
• It retains OSG's proven DNA while modernizing the architecture
• Recent developments such as hardware-accelerated ray-tracing and mesh shaders are not available through OpenGL extensions

For new projects requiring cutting-edge features, it is recommended to evaluate VulkanSceneGraph as an alternative to OpenSceneGraph.

Practical Applications and Use Cases

OpenSceneGraph finds applications in many fields requiring advanced 3D visualization and interoperability with CAD data:

Industrial Simulations and Training

OpenSceneGraph is widely used for flight, marine, vehicular, and space simulations. These applications benefit from OSG's ability to:

• Handle complex 3D scenes with a high level of detail
• Maintain high performance even with large models
• Integrate data from different CAD systems

Scientific and Medical Visualization

Scientific and medical visualization represents another major application area for OpenSceneGraph. Researchers and healthcare professionals use OSG to:

• Visualize complex 3D data
• Interact with models in real-time
• Share and collaborate on visualizations

Virtual and Augmented Reality

With the rise of immersive technologies, OpenSceneGraph plays an important role in developing virtual and augmented reality applications. SimLab VR Studio and SimLab VR Viewer notably allow:

• Creating VR experiences from existing 3D models
• Facilitating immersive training
• Presenting products and concepts in virtual reality

OpenSceneGraph offers a mature and proven solution for CAD data interoperability in the context of 3D visualization and virtual reality. Although the project is now in a maintenance phase, its stability, performance, and well-developed ecosystem still make it a relevant choice for many industrial and scientific projects. For applications requiring the latest technological advances, the evolution toward VulkanSceneGraph represents a promising path forward.

• CADfix
• 3DViewStation
• SimLab

Table of Contents

1. History and Development of OpenCTM
2. Technical Characteristics and Advantages
3. Comparison with Other 3D Visualization Formats
4. Tools and Applications Associated with OpenCTM
5. CAD Interop Solutions Compatible with OpenCTM
6. Use Cases and Practical Applications
7. Best Practices for OpenCTM File Exchange
8. Conclusion and Future Perspectives

OpenCTM (Open Compressed Triangle Mesh) is a file format specifically designed to store 3D triangular meshes in an extremely compact manner. Unlike other CAD exchange formats that handle a multitude of information (assemblies, construction history, material properties), OpenCTM focuses exclusively on the efficient representation of triangular meshes.

This format is not a complete scene description format, but rather a 3D data carrier that can be integrated into different environments. Its flexibility allows for adoption in many fields requiring efficient 3D visualization: CAD systems, game engines, medical applications, or virtual reality solutions.

OpenCTM's minimalist approach makes it a sensible choice for applications where lightweight files and fast loading times are paramount, while maintaining a faithful representation of complex geometries.

History and Development of OpenCTM

Origins and Creation

OpenCTM was developed by Marcus Geelnard, with the first version published in 2009. The project was born from the need for an open format capable of efficiently storing large 3D meshes without significant quality loss. The stable version 1.0.3, released on January 15, 2010, remains the current reference.

The name "OpenCTM" reflects the philosophy of the project:

• "Open" emphasizes its nature as an open format
• "CTM" stands for Compressed Triangle Mesh

Technological Evolution

The project was structured around three essential components:

• An open binary file format (.ctm)
• An open-source software library for reading and writing OpenCTM files
• A set of tools for converting and visualizing OpenCTM files

OpenCTM's architecture was designed to be compatible with high-performance graphic rendering pipelines such as OpenGL, making it a particularly suitable solution for interactive graphic applications. This performance-oriented design explains why the format quickly established itself in fields requiring fluid and responsive 3D visualization.

Technical Characteristics and Advantages

Format Specifications

The OpenCTM format presents several advanced technical characteristics:

• Binary format using 32-bit little-endian format for integers and IEEE 754 32-bit format for floating-point numbers
• Identification by the "OCTM" signature (0x4D54434F in hexadecimal) at the beginning of the file
• Internal structure optimized for geometric data compression
• Use of a triangular index array to represent connectivity information
• Multiple arrays to represent vertex data (coordinates, normals, UV coordinates)

Key Advantages for CAD Interoperability

The OpenCTM format offers several significant advantages for 3D data exchange:

• Exceptional compression: An STL file can generally be compressed to 5-6% of its original size, significantly reducing storage needs and transfer times
• Precision flexibility: Lossless compression options (IEEE 754 32-bit floating point) or fixed-point representation with controllable precision
• Support for advanced attributes: Storage of per-vertex normals, UV coordinates, and custom attributes
• Massive geometry processing capability: Management of billions of triangles and vertices
• Open format: Distributed under the zlib/libpng license, promoting integration in various software solutions

These characteristics make OpenCTM a particularly suitable solution for contexts requiring efficient transfer of large 3D data, such as remote visualization, mobile applications, or web platforms.

Comparison with Other 3D Visualization Formats and VR/AR

The choice of a 3D visualization format often depends on the specific needs of the project. Here is a comparison between OpenCTM and three major equivalent formats used in 3D visualization and virtual/augmented reality:

This comparison highlights OpenCTM's specialization in the efficient compression of triangular meshes, while other formats offer more extensive functionality for complete scene description. The choice between these formats will depend on specific needs in terms of CAD interoperability, performance, and visual fidelity.

Tools and Applications Associated with OpenCTM

Development Library

The OpenCTM library provides developers and 3D designers with the necessary tools to integrate the format into their applications. Written in C, it offers a solid foundation for reading and writing OpenCTM files on various platforms (Windows, Mac OS X, Linux, etc.).

3D Converter (ctmconv)

The ctmconv converter represents an essential tool in the OpenCTM ecosystem, offering the following functionalities:

• Bidirectional conversion between OpenCTM and various common 3D formats:
  • COLLADA 1.4/1.5 (.dae)
  • Stereolithography (.stl)
  • Stanford Triangle Format (.ply)
  • 3D Studio (.3ds)
  • Wavefront Geometry (.obj)
  • LightWave Object (.lwo)
  • Geomview Object (.off)
• Precise control of OpenCTM compression parameters
• Model transformation and scaling operations
• Cross-platform compatibility for flexible integration in different work environments

OpenCTM Viewer (ctmviewer)

The ctmviewer application completes the tool suite by offering:

• Interactive 3D visualization via OpenGL
• GLSL-based Phong shading for realistic rendering
• Support for texturing and vertex colors
• Fast loading ideal for previewing 3D files
• Import/export capabilities to formats supported by the conversion tool
• Portability across different platforms (Windows, Mac OS X, Linux, etc.)

These tools form a coherent ecosystem allowing users to work efficiently with the OpenCTM format throughout their 3D processing chain.

CAD Interop Solutions Compatible with OpenCTM

CAD Interop distributes several software solutions capable of preparing, visualizing, and converting OpenCTM files, thus strengthening CAD data interoperability in design and visualization environments.

SimLab for Creating Immersive Experiences

SimLab represents a flagship solution distributed by CAD Interop to fully exploit the potential of the OpenCTM format in virtual and augmented reality contexts. This comprehensive platform allows transforming OpenCTM models into rich and interactive immersive experiences.

SimLab VR: a complete ecosystem

The SimLab VR platform integrates several complementary components:

• SimLab Studio: Central tool allowing simplified construction of VR scenes from 3D models, including those in OpenCTM format. Key features include:
  • Intuitive construction of VR scenes without requiring advanced programming skills
  • Import and export adapted to essential formats, including OpenCTM
  • Creation of interactive elements such as quizzes and surveys in the VR environment
  • Detailed analysis of user engagement to optimize the experience
• SimLab VR Viewer: Free virtual reality visualization application compatible with OpenCTM models, offering:
  • Cross-platform compatibility (computer, smartphone, tablet, VR headset)
  • Immersive experience to interact with 3D models
  • Intuitive interface facilitating understanding of simulations
• SimLab Collaboration Add-on: Extension enriching the experience by enabling collaborative sessions between users, transforming the visualization of OpenCTM models into an interactive and shared activity.

The integration of the OpenCTM format in the SimLab ecosystem demonstrates its value for advanced visualization applications, where efficient mesh compression allows optimal performance even with complex models.

Use Cases and Practical Applications

Lightweight Visualization of Complex Models

OpenCTM's exceptional compression (reduction up to 95% compared to STL format) makes it a preferred solution for visualizing complex CAD models in environments where resources are limited. Design offices can thus quickly share detailed models with remote collaborators without requiring specialized hardware.

Optimization for Mobile and Web Applications

3D visualization applications on mobile platforms particularly benefit from the OpenCTM format. The drastic reduction in file size allows for accelerated loading times and reduced bandwidth consumption, improving the user experience on mobile devices.

Model Preparation for Virtual and Augmented Reality

In the VR/AR domain, where performance is crucial to maintaining a fluid experience, OpenCTM offers an excellent compromise between visual fidelity and lightweight files. Complex CAD models can be converted to OpenCTM and then integrated into immersive environments via solutions like SimLab VR.

Optimized Technical Archiving

For companies managing large amounts of CAD data, OpenCTM represents an efficient archiving solution. Lossless compression allows for preserving all geometric information while significantly reducing the required storage space, generating significant savings on IT infrastructure.

Best Practices for OpenCTM File Exchange

To maximize the benefits of the OpenCTM format in your CAD interoperability workflows, here are some practical recommendations:

Conversion Optimization

• Precision Level Adjustment: Adapt the precision level according to the final use. Maximum precision is recommended for demanding technical applications, while reduced precision may be sufficient for simple visualization.
• Mesh Preprocessing: Clean and optimize your meshes before conversion to OpenCTM to improve compression rates:
  • Removal of degenerate triangles
  • Repair of holes and non-manifold surfaces
  • Optimization of mesh topology
• Preservation of Essential Attributes: Identify critical vertex attributes (normals, UV coordinates) to preserve during conversion to maintain the visual quality of the model.

Integration into Workflows

• Conversion Automation: Implement scripts or automated workflows for batch conversion of multiple files to OpenCTM, particularly useful in production environments.
• External Metadata: Consider storing metadata and non-geometric information in complementary files, as OpenCTM focuses exclusively on geometry.
• Post-Conversion Validation: Establish a validation process to verify the integrity of models after conversion, comparing original and converted files both visually and metrically.

Specific Technical Considerations

• Management of Very Large Models: For extremely large models, consider segmenting them into smaller components before conversion to OpenCTM, then reassembling them in the target application.
• Optimal Compression Parameters: Experiment with different compression parameters to find the best balance between file size and fidelity for your specific use case.
• VR Headset Compatibility: For VR applications, limit the complexity of OpenCTM meshes to approximately 1-2 million triangles per scene to maintain fluid performance on most current VR headsets.

Applying these best practices will allow for effectively integrating OpenCTM into your CAD interoperability processes, thus optimizing workflows for 3D data visualization and exchange.

Conclusion and Future Perspectives

The OpenCTM format represents a specialized and high-performance solution for 3D mesh data interoperability in the CAD ecosystem. Its ability to efficiently compress complex geometries while preserving essential details makes it a valuable tool for lightweight visualization and 3D model exchange.

Although more targeted than complete scene description formats like glTF or FBX, OpenCTM excels in its area of specialization: efficient compression of triangular meshes. This specialization makes it an ideal complement to traditional CAD exchange formats in workflows requiring high-performance visualization.

The integration of OpenCTM in solutions like SimLab VR demonstrates its continued relevance in a world where 3D visualization, virtual reality, and augmented reality are becoming essential tools for industry. Its nature as an open format and its cross-platform compatibility also ensure its durability in a constantly evolving technological ecosystem.

For companies seeking to optimize their CAD data exchange and visualization processes, OpenCTM constitutes a solution worth serious consideration, offering an optimal balance between performance, fidelity, and accessibility.

• SimLab

Table of Contents

1. Introduction and uses of Maya
2. Native formats and interoperability of Maya files
3. SimLab Composer: Creating immersive experiences from Maya models
4. Best practices for data exchange with Maya
5. Conclusion: Optimizing Maya integration in your CAD ecosystem

Maya is a 3D graphics software developed by Autodesk that plays a key role in modern CAD interoperability. Although primarily designed for creative industries, its exchange capabilities with traditional CAD systems make it a valuable tool for many industrial sectors. This article explores in detail the interoperability mechanisms around Maya and the solutions available to facilitate exchanges with other technical environments.

Introduction and uses of Maya in the CAD ecosystem

Maya has established itself as a standard in the entertainment industry, but its use extends far beyond that today. This powerful software offers a complete set of tools for 3D modeling, animation, and rendering.

Main application areas:

• Production of visual effects for film and television
• Design of video games and virtual environments
• Architectural visualization and industrial simulation
• Virtual product prototyping
• Photorealistic renderings for product design

The convergence between the worlds of traditional CAD and artistic 3D creation is accelerating, requiring increasingly powerful interoperability bridges. Maya stands out for its ability to maintain the visual richness of models while allowing bidirectional exchanges with engineering software.

Native formats and interoperability of Maya files

Interoperability around Maya relies on its ability to read and write numerous formats, whether they are native or exchange standards. This flexibility facilitates the integration of Maya into complex multi-CAD workflows.

Maya native formats:

Supported CAD exchange formats and standards:

This wide compatibility makes it possible to establish bridges between Maya and the main CAD systems on the market, including AutoCAD, SolidWorks, and Inventor. Users can thus import CAD models, enhance them with Maya's creative capabilities, and then export them in their original format or to standard exchange formats such as STEP or JT.

How to optimize exchanges between Maya and CAD systems?

The transfer of data between Maya and traditional CAD software requires some precautions to preserve the integrity of the models. Here are the essential points of attention:

• Geometric data translation: When importing/exporting, ensure that the units of measurement are correctly defined to avoid scaling issues
• Geometric healing: Imported CAD models may require surface repair to function correctly in Maya
• Mesh management: The conversion between B-rep representation (used in CAD) and mesh (preferred in Maya) requires special attention
• Metadata preservation: Non-geometric information must be preserved via attributes or auxiliary files

Interoperability with Maya is part of a broader approach to technical data exchange that must address the challenges of design, simulation, manufacturing, and archiving.

SimLab Composer: Creating immersive experiences from Maya models

CAD Interop distributes SimLab Composer, a powerful solution for integration with Maya. This software acts as an intermediate layer between Maya and other applications, creating an active link that keeps the data synchronized.

Key features of SimLab Composer for Maya:

• Seamless integration: The Maya integration plugin is a free tool that facilitates design sharing between Maya and SimLab Composer
• Interactive visualization: Quickly create VR experiences from Maya models in minutes
• Realistic rendering: Fast and photorealistic rendering with different outputs (images, videos, animations, 360° images)
• 3D PDF export: Share your work by integrating 3D views into PDF files
• Texture baking: Apply materials and bake textures for realistic rendering when sharing in 3D PDF and WebGL

The plugin supports Maya 2023 and earlier versions, working on Windows and macOS. The default settings work automatically for most models, but the user retains control over the scale and vertical vector to use.

Best practices for data exchange with Maya

To optimize interoperability between Maya and other CAD systems, a few recommendations are necessary:

• Prepare models before export: Simplify complex geometries and clean up unnecessary elements
• Choose the appropriate exchange format: Favor FBX for exchanges with other Autodesk tools and OBJ/STL for universal compatibility
• Validate geometric quality: Check the integrity of surfaces and volumes after conversion
• Document transformations: Keep track of operations performed during conversion to facilitate debugging
• Use validation tools: Implement quality control processes for exchanged models

These best practices are part of a more global CAD interoperability approach that covers all the company's needs: integration, visualization, documentation, analysis, and data preparation for different uses.

Conclusion: Maya in your CAD interoperability strategy

Maya represents a valuable link in the modern CAD interoperability chain, particularly when projects require advanced visualization capabilities and photorealistic rendering. Its integration into a multi-CAD ecosystem allows leveraging its powerful animation and modeling features while maintaining consistency with other engineering systems.

With solutions like SimLab Composer distributed by CAD Interop, companies can streamline exchanges between Maya and other technical environments, paving the way for innovative applications in virtual reality and immersive visualization.

The adoption of an interoperability strategy including Maya must be based on a thorough understanding of exchange formats, validation processes, and best practices to ensure data integrity throughout the product lifecycle.

• SimLab

Table of Contents

• History and Evolution of the LightWave Format
• Technical Characteristics of the LightWave Format
• LightWave in the CAD Interoperability Ecosystem
• Comparison with Other 3D Visualization Formats
• Best Practices for LightWave File Exchange
• Practical Applications and Use Cases

In an industrial environment where 3D data interoperability is crucial, the LightWave format stands out as a powerful solution for modeling, animation, and rendering. Technical visualization and CAD professionals are constantly seeking efficient ways to convert, visualize, and integrate LightWave models into their multi-software workflows, making the understanding of this format a valuable skill in the CAD interoperability ecosystem.

History and Evolution of the LightWave Format

LightWave 3D was originally developed by NewTek (now LightWave Digital) and made its debut in 1988 under the name "Videoscape". Created by Allen Hastings for the Amiga platform, this software quickly distinguished itself through its exceptional rendering quality and remarkable productivity.

The chronological evolution of the format is significant in the history of 3D visualization:

• 1988: Initial creation under the name "Videoscape"
• 1990s: Massive adoption in the television industry
• 1994: Release of the standalone version (LightWave 3.5) following user demand
• 2009: Announcement of LW CORE, a complete redesign of the software
• 2024: Current version 2024.1.0, continuously improved and optimized

LightWave was particularly prominent in television productions of the 90s such as The X-Files, Babylon 5, and SeaQuest DSV, as well as in iconic films like Titanic and Jurassic Park thanks to renowned studios such as Digital Domain and ILM. LightWave version 6 distinguished itself as the first 3D software to integrate HDRI and one of the first to use radiosity, marking a significant advancement in the field of 3D visualization.

Technical Characteristics of the LightWave Format

LightWave File Structure

LightWave primarily uses two distinct types of files that work in symbiosis to create complete 3D visualizations:

• Object files (.lwo): Binary format storing the raw geometry of 3D objects
• Scene files (.lws): ASCII format containing scene descriptions, lighting, and animations

This separation offers considerable flexibility in managing complex projects and facilitates interoperability with other CAD and visualization systems.

Main Technical Features

The LightWave engine integrates numerous advanced capabilities that make it a valued tool for technical visualization:

• Fast rendering engine with realistic reflection, radiosity, and caustics
• Support for 999 render nodes for large-scale projects
• Polygonal modeling and subdivision surfaces
• Animation via inverse and forward kinematics
• Particle systems and physical dynamics

Specific Technologies

LightWave is distinguished by several proprietary technologies that enhance its technical visualization capabilities:

• Hypervoxels: Particle rendering technology allowing simulation of:
  • Metaballs for liquids
  • Sprites for effects like fire
  • Volume shading for clouds and fog
• Advanced material shaders:
  • Subsurface scattering for translucent materials
  • Realistic multi-layer skin models
  • Metallic shaders with energy conservation
  • Precise refraction simulation with total internal reflection

These technical characteristics make LightWave a particularly suitable tool for high-quality CAD visualizations and the exchange of complex technical data.

LightWave in the CAD Interoperability Ecosystem

Native Import/Export Capabilities

One of LightWave's major strengths lies in its ability to interact with many standard formats used in the CAD and 3D visualization ecosystem:

• Generic 3D formats: OBJ, DXF, 3DS, DAE (COLLADA), FBX, STL, PLY
• Data preservation level:
  • OBJ, DXF, 3DS: Support for surfaces, textures, and UV coordinates
  • FBX: Additional support for morphing information

This versatility makes it a tool of choice for interoperability in multi-CAD and multi-software projects.

Integration with Game Engines and Visualization Platforms

LightWave integrates effectively with major visualization platforms and modern 3D engines:

• Unreal Engine: Integration via NewTek's NDI® network discovery mechanism (since LightWave 2019)
• Unity: Direct support via LightWave Importer for Unity which allows native import of .lwo and .lws files

For Unity specifically, LightWave Importer offers extended features such as:

• Importing triangles, quads, and ngons with multiple holes
• Support for subpatch surfaces with various texture mapping methods
• Automatic conversion of LightWave materials to Unity materials

SimLab VR Studio for LightWave

SimLab VR Studio represents a complete solution for transforming LightWave models into interactive VR experiences, particularly suited for technical presentations and virtual exhibitions.

Key capabilities of SimLab VR with LightWave files:

• Creation of immersive VR experiences from existing LightWave models
• Real-time communication with the audience to discuss visualized products
• Customization of the customer experience in an interactive 3D environment

Practical applications in the professional context:

SimLab VR Studio allows the creation of two types of experiences particularly relevant for LightWave users:

1. Virtual exhibition stands:
   • Prior visualization of exhibition stand designs
   • Presentation of different configuration options and materials
   • Collaborative revision of designs with clients
2. Complete virtual exhibitions:
   • Creation of entirely virtual exhibition spaces
   • Presentation of the entire product catalog without physical constraints
   • Collaborative sessions with clients and partners

The SimLab VR platform offers a comprehensive set of tools for creating, visualizing, distributing, and collaborating in virtual environments, thus representing a natural extension of LightWave's visualization capabilities in the field of virtual reality for technical and industrial applications.

Cloud and Collaborative Integration

Recent developments have also improved cloud integration and collaboration capabilities:

• Advanced image caching technology (since LightWave 2019)
• Procedural shader nodes for third-party textures and materials
• Grid filtering tools, level set tracking, and fluid simulation

These features strengthen LightWave's position as an important link in the CAD data interoperability chain, particularly for advanced technical visualization workflows.

Comparison with Other 3D Visualization Formats

CAD and technical visualization professionals often need to choose between different formats for 3D data exchange. Here's how LightWave compares to the three other major industry formats:

How to choose the appropriate format?

The choice between LightWave and other formats generally depends on several critical factors for CAD interoperability:

• For long-term archiving: COLLADA offers better durability thanks to its open XML structure
• For exchange with CAD tools: FBX and OBJ are generally better natively supported
• For preserving complex animations: LightWave and FBX are preferable
• For simplicity and universal compatibility: OBJ remains the most widely adopted format

This comparison highlights the importance of a CAD interoperability strategy that takes into account the specific strengths of each format according to the context of use and technical data preservation needs.

Best Practices for LightWave File Exchange

Exchanging LightWave files with other systems requires certain precautions and techniques to ensure the integrity and fidelity of the models. Here are the best practices recommended by experts and gathered from specialized forums.

Conversion between LightWave and Other 3D Software

To optimize conversion to and from LightWave:

• Using OBJ format as an intermediate: To export from LightWave to other software like ZBrush, favor exporting to OBJ then importing into the target application
• Directory structure: Maintain a consistent organization with separate folders for scenes, objects, and images to preserve links between files during import/export
• Path management: Correctly configure the "Path to Content Directory" when importing LightWave files to avoid missing file errors

Optimization of Normal Maps and Textures

For normal maps and textures between LightWave and other applications like ZBrush:

• Export configuration: In ZBrush, enable the "Normal Map Flip X" and "Normal Map Flip Z" options in the preferences before exporting
• UV coordinate management: For models with complex UVs, note that coordinates may require a 180-degree rotation and horizontal flip when moving between LightWave and certain software
• Normal map shaders: Use specialized shaders like TB's Normal Map for LightWave when importing normal maps from other applications

Resolving Common Issues

Specific difficulties may arise when converting between LightWave and CAD systems:

• Large files: For complex models (>60MB), consider simplification or segmentation before conversion to native CAD formats
• Conversion errors: If direct conversion fails, try using a standard intermediate format before targeting the final format
• Version compatibility: Be attentive to differences between LightWave versions (5.6 or 6.0+), particularly regarding polygon limits (65535 for v5.6) and UV coordinate support

Integration with Unity

For specific integration with Unity:

• Using LightWave Importer: Install the LightWave Importer package for Unity to work directly with .lwo and .lws source files without requiring intermediate conversion
• Layer activation/deactivation: Take advantage of the ability to activate/deactivate specific layers during import to process only the necessary elements
• Special geometry conversion: Use the conversion features for 2-point polygons and curves to Ribbon geometry in Unity to preserve these particular elements

These best practices, derived from the collective experience of professional users, allow optimization of workflows involving LightWave and minimize problems when exchanging data with other CAD and 3D visualization systems.

Practical Applications and Use Cases

The interoperability of the LightWave format finds concrete applications in several industrial domains where 3D visualization and technical data exchange are essential.

Architectural Visualization and Interior Design

LightWave has established itself as a valuable tool for architectural visualization, particularly thanks to its integration with Unreal Engine:

• Creation of interactive virtual tours of buildings
• Production of photorealistic architectural renderings
• Real-time collaboration between architects and interior designers
• Rapid visual validation of concepts with clients

Audiovisual Production and Visual Effects

Historically dominant in this sector, LightWave continues to offer crucial interoperability capabilities:

• Transfer of models between departments using different 3D software
• Bidirectional conversion between animation and VFX software
• Previsualization of visual effects sequences
• Long-term archiving of production assets

LightWave data interoperability remains a technical challenge but is surmountable thanks to specialized tools and established best practices. By understanding the specific strengths and limitations of the LightWave format in different contexts of use, professionals can optimize their workflows and take full advantage of this powerful and flexible 3D visualization ecosystem.

Solutions distributed by CAD Interop, such as SimLab VR Studio, offer extended capabilities that enrich the value of LightWave models by making them accessible in immersive and collaborative environments, thus reinforcing their utility in modern professional contexts.

• CADfix
• SimLab

In today's industrial environment, CAD data interoperability represents a major challenge for companies handling complex 3D models. The PLY format (Polygon File Format), also known as the Stanford Triangle Format, occupies a special place in this ecosystem as a gateway between 3D data acquisition and computer-aided design processes. Initially developed to meet the needs of computer graphics researchers, PLY is now widely used in industrial workflows involving point clouds and polygonal meshes. Its growing adoption, however, comes with technical challenges related to conversion, visualization, and optimal exploitation of this data in multi-CAD environments.

Table of contents

1. The fundamentals of PLY format in the CAD ecosystem
2. Conversion strategies between PLY and parametric CAD formats
3. Integration of PLY in 3D scanning workflows
4. Comparative analysis between PLY and other mesh formats
5. Software solutions and tools for optimal exploitation of PLY

The fundamentals of PLY format in the CAD ecosystem

The PLY format, created in 1994 by Greg Turk of Stanford University, was specifically designed to store three-dimensional data from scanners. Its distinctive technical structure combines simplicity and versatility, allowing it to represent a variety of geometric and visual information. A thorough understanding of its characteristics is essential to ensure effective CAD interoperability.

Structure and technical specifications of the PLY format

A PLY file consists of two main sections: a header in ASCII format followed by a data block that can be in ASCII or binary. The header defines the elements contained in the file, their properties, and the number of instances. This modular structure allows the PLY format to adapt to various design and engineering applications.

The main technical characteristics of the PLY format include:

• Ability to store polygonal meshes (usually triangular)
• Support for vertex coordinates (x, y, z)
• Storage of surface normals for enhanced rendering
• Representation of colors by vertex or face (RGB or RGBA)
• Ability to include texture information
• Management of custom properties for specific applications
• Data compression using the binary version

The flexibility of the format allows choosing between two variants: ASCII and binary. The ASCII version offers better readability and universal compatibility, facilitating debugging and manual editing. In contrast, the binary version generates more compact files and allows faster processing, making it particularly suitable for large complex 3D datasets.

Role of PLY in the CAD interoperability ecosystem

In the digital design value chain, the PLY format plays a bridging role between real data acquisition and structured CAD modeling. Its ability to faithfully represent complex geometries from 3D scanning makes it a preferred format for the early stages of reverse engineering and reality-based design.

PLY integrates into the CAD ecosystem at several levels:

• As an output format for 3D scanning equipment
• As an intermediate format for point cloud processing
• As a visual reference for parametric CAD modeling
• For validation of CAD models by comparison with scanned physical parts
• In virtual and augmented reality workflows

For companies handling both structured CAD data and representations from the real world, the PLY format constitutes an important link in the technical data interoperability chain. Its support by numerous CAD systems and 3D processing software facilitates data exchange between departments using different tools.

Conversion strategies between PLY and parametric CAD formats

Converting PLY files to parametric CAD formats represents a major technical challenge due to fundamental differences between mesh representations and feature-based models. This transformation requires specific strategies to preserve data integrity and ensure optimal interoperability.

Technical challenges of converting mesh to parametric model

The transition from a mesh format like PLY to a parametric format like STEP involves a complete reinterpretation of geometric data. This conversion faces several obstacles:

• PLY meshes represent surfaces approximated by facets, while parametric models use precise mathematical surfaces
• Design information (history, constraints, parameters) is absent from PLY files
• The quality and density of the mesh directly influence the precision of the converted model
• CAD features (holes, fillets, chamfers) must be reconstructed through shape recognition
• Geometric tolerances can be difficult to maintain during conversion

To overcome these challenges, the conversion process generally requires several intermediate processing steps, including mesh simplification, feature detection, and surface reconstruction.

Optimal methods and workflows for PLY-STEP conversion

Effective conversion of PLY data to the STEP standard (ISO 10303) requires a methodical approach to maximize geometric fidelity. An optimal workflow includes:

1. PLY mesh preparation:
   • Cleaning artifacts and outliers
   • Controlled decimation to reduce complexity
   • Surface smoothing to eliminate noise
   • Geometric healing to correct topological problems
2. Intelligent segmentation:
   • Identification of different geometric regions
   • Recognition of primitives (planes, cylinders, spheres)
   • Detection of sharp edges and discontinuities
3. Parametric reconstruction:
   • Generation of NURBS surfaces from identified segments
   • Application of surface fitting algorithms (best-fit)
   • Reconstruction of CAD features (extrusions, revolutions)
   • Definition of relationships between geometric elements
4. Validation and optimization:
   • Analysis of deviations between the original mesh and the STEP model
   • Adjustment of tolerances to balance precision and performance
   • B-rep optimization to improve compatibility

The different versions of the STEP format (AP203, AP214, AP242) offer variable capabilities for representing data converted from PLY. AP242, in particular, offers advanced features for mesh representation and preservation of PMI (Product Manufacturing Information), making it a preferred option for PLY conversions requiring maximum semantic richness.

Preservation of critical information during conversions

When converting a PLY file to a structured format like STEP, some information may be lost or altered. It is crucial to identify the essential data to preserve based on the specific needs of the project:

• Basic geometry: The general shape must be preserved with sufficient precision for the targeted application
• Colors and textures: This visual information can be preserved in certain STEP implementations
• Metadata: Custom properties must be mapped to equivalent attributes in the target format
• Dimensional tolerance: Geometric deviations must remain within acceptable limits for manufacturing

For critical applications such as aerospace or automotive, rigorous validation processes are necessary to ensure that converted models meet engineering requirements and specified tolerances.

Integration of PLY in 3D scanning workflows

The PLY format has established itself as a de facto standard in 3D scanning processes due to its ability to faithfully capture data from scanners. Its effective integration into engineering workflows represents a strategic issue for companies adopting reality-based design approaches.

Acquisition and processing of 3D scan data in PLY format

The process of acquiring 3D data generating PLY files comprises several crucial technical steps to ensure model quality:

1. Configuration and calibration of scanning hardware:
   • Adjustment of resolution and precision parameters
   • Calibration of sensors to minimize distortions
   • Determination of acquisition strategy (number of views, positions)
2. Raw data acquisition:
   • Capture of point clouds with overlap between scans
   • Recording of complementary information (colors, textures)
   • Management of lighting conditions and reflective surfaces
3. Initial post-processing:
   • Alignment and fusion of different views
   • Filtering noise and outliers
   • Generation of polygonal mesh from point cloud
   • Export to PLY format with appropriate metadata

The quality of the PLY data obtained depends heavily on the scanner resolution, processing algorithms used, and the nature of the scanned object. Shiny, transparent, or very dark surfaces can present particular challenges requiring specific acquisition techniques.

Optimization of PLY files for reverse engineering

PLY files from 3D scanning generally require optimization before they can be effectively exploited in reverse engineering processes:

• Intelligent decimation: Reduction of polygon count while preserving important geometric details
• Adaptive smoothing: Elimination of noise while preserving sharp edges
• Hole filling: Completion of uncaptured areas by geometric interpolation
• Segmentation: Identification of distinct regions to facilitate CAD reconstruction
• Feature extraction: Automatic detection of elements such as planes, cylinders, holes

These optimization operations are essential for transforming raw PLY data into exploitable models in structured CAD environments. They not only improve the geometric quality of the models but also facilitate their subsequent conversion to parametric formats.

Use case: From scanning to CAD via PLY format

A concrete application case illustrates the use of the PLY format in a complete reverse engineering workflow for the aeronautical sector:

An aeronautical equipment manufacturer needed to recreate a parametric CAD model of a complex mechanical part whose original plans were incomplete. The process involved:

1. Scanning the physical part using a high-precision 3D scanner
2. Exporting the raw data to PLY format (binary) to preserve all geometric details
3. Processing the PLY mesh to eliminate imperfections and optimize topology
4. Automatic segmentation of the model into functional regions
5. Parametric reconstruction with CAD feature generation
6. Conversion to STEP AP242 for integration into the PLM system
7. Dimensional validation by comparison between the final model and the original scan

This workflow reduced development time by 75% compared to manual modeling while ensuring dimensional accuracy of around 0.05 mm. The use of PLY format as an intermediate was crucial for preserving subtle geometric details of the original part.

Comparative analysis between PLY and other mesh formats

In the ecosystem of 3D representation formats, PLY coexists with several other mesh standards, each presenting specific advantages and limitations. A comprehensive comparative analysis helps determine the optimal usage contexts for each format and improve overall CAD interoperability.

Technical comparison between PLY, STL, and OBJ

These three mesh formats are among the most used in the industry, but present significant differences in terms of capabilities and use cases:

The PLY format stands out for its flexibility and ability to store rich information beyond simple geometry. This characteristic makes it particularly suitable for applications requiring the preservation of attributes such as colors, normals, or domain-specific properties.

Advantages and limitations of PLY for CAD interoperability

The PLY format presents several distinctive advantages for technical data interoperability:

Strengths:

• Extensible structure allowing addition of custom properties
• Native support for colors and textures without external files
• Ability to store properties by vertex, edge, or face
• Well-documented format with stable specification
• ASCII and binary versions for different needs (debug vs performance)
• Efficient processing of large datasets in binary mode

Limitations:

• Less widespread than STL in certain industrial sectors
• Generally larger file size than STL
• Increased complexity for manual editing (compared to OBJ)
• Lack of support for groups and object hierarchies (unlike OBJ)
• Limited support for NURBS and parametric surfaces
• Implementation variations between different software

These characteristics make PLY a preferred choice for specific applications such as 3D metrology, reverse engineering, and advanced technical visualization, but may make it less suitable for other use cases such as 3D printing where the STL format remains predominant.

Selection criteria for optimal format according to industrial context

The choice between PLY and other mesh formats should be guided by the specific requirements of the project and the industrial context:

For 3D scanning and metrology:

• Prefer PLY for its ability to preserve color information and custom properties
• Use the binary version for volumetric point clouds
• Maintain acquisition metadata for traceability

For 3D printing:

• STL generally remains more appropriate due to its simplicity and universal compatibility
• PLY may be preferred if color preservation is necessary (multi-material printing)
• Consider converting PLY to STL for standard printing workflows

For reverse engineering:

• PLY constitutes an excellent intermediate format before CAD reconstruction
• Its ability to store precise normals facilitates curvature analysis
• The extensibility of the format allows inclusion of confidence data by region

For technical visualization and collaboration:

• PLY offers a good balance between visual richness and performance
• OBJ may be preferred for applications requiring high-quality rendering
• Conversion to JT or 3D PDF may be necessary for wide distribution

In demanding sectors such as aeronautics, automotive, or medical, format selection must also take into account long-term archiving standards and domain-specific regulatory requirements.

Software solutions and tools for optimal exploitation of PLY

Effective use of the PLY format in an industrial environment requires specialized software solutions for visualizing, converting, and exploiting this 3D data. A combination of adapted tools allows creating fluid and high-performance CAD interoperability workflows.

Visualization and analysis of PLY files with SimLab

Effective visualization of PLY data is an essential first step to assess quality and exploit the information contained in these files. SimLab offers advanced visualization solutions particularly suited to PLY files1:

• High-performance display of voluminous meshes through graphic optimization techniques
• Multiple rendering modes (wireframe, solid, textured, points) for different analyses
• Precise measurement tools for dimensional analysis of PLY models
• Section and cutting functions for internal inspection of meshes
• Comparison with reference CAD models by color map
• Native support for PLY-specific properties such as vertex colors
• Visualization filters to highlight certain model characteristics

SimLab Composer, as a complete 3D visualization solution, offers an intuitive interface allowing exploration of PLY files with great fluidity2. Its ability to import 3D models from different CAD formats, including PLY, makes it a versatile tool for technical data interoperability.

Transformation of PLY data into immersive experiences

Converting PLY files to immersive environments represents a growing trend in industry. SimLab particularly excels in this domain by offering specific features:

• Direct import of PLY files into the SimLab Composer environment
• Smooth conversion to interactive VR experiences without programming
• Preservation of colors and textures of the PLY model in the virtual environment
• Creation of animations and simulations based on initial PLY data
• Addition of interactions and behaviors to imported PLY objects
• Generation of complementary visual effects enriching the user experience
• Sharing experiences via the cloud for visualization on different VR devices

SimLab VR Studio specifically allows transforming PLY files into complete VR experiences without requiring programming skills. This "no-code" approach democratizes the creation of virtual environments from 3D scanning data, making this technology accessible to a wider range of technical professionals.

Advanced collaboration solutions for PLY files

Collaborative exploitation of PLY files constitutes a major challenge for companies working on complex projects involving multiple departments. SimLab offers dedicated features for this aspect:

• Sharing PLY models via the cloud in different formats (VR, WebGL, 360° images)
• Real-time VR collaboration between multiple users viewing the same model
• Centralized hosting of optimized PLY files for distributed access
• Collaborative annotations on models to facilitate technical communication
• Synchronization of modifications between different platforms and devices
• Organization of design review sessions in shared virtual environment
• Integration with LMS systems for PLY-based training applications

SimLab Collaboration allows multiple users to interact simultaneously with PLY models in a shared virtual environment. This functionality transforms the way technical teams collaborate around 3D scanning data, facilitating exchanges between designers, engineers, and domain experts.

Automation of PLY file processing

For companies regularly processing large volumes of PLY data, workflow automation represents a major efficiency lever. SimLab offers several features in this area:

• Batch conversion of PLY files to different target formats
• Automation scripts for repetitive operations on PLY meshes
• Automated processing of optimizations (decimation, smoothing, healing)
• Programmed generation of renderings and visualizations from PLY models
• Automated distribution and publication of processed models
• Integration with PLM systems for PLY data lifecycle management
• Predefined workflows adapted to different industrial sectors

SimLab CADVRter particularly stands out for automating conversion between PLY formats and VR environments. This solution allows establishing standardized processing pipelines, ensuring consistency and efficiency in 3D scanning data management at the enterprise scale.

How to solve common problems with PLY files?

PLY file users may encounter various technical challenges requiring specific approaches:

Problem: Large meshes affecting performance

• Solution: Use SimLab capabilities for optimized visualization of voluminous models
• Apply SimLab's intelligent decimation techniques preserving important characteristics
• Exploit the level of detail (LOD) functionalities of SimLab Composer to adapt complexity to usage

Problem: Information loss during conversions

• Solution: Use SimLab's advanced import/export options to preserve essential attributes
• Exploit the flexibility of the PLY format in combination with SimLab capabilities to maintain metadata
• Validate conversions via visual comparison tools integrated into SimLab Composer

Problem: Collaboration on voluminous PLY files

• Solution: Use SimLab VR Viewer to efficiently share models between remote teams
• Exploit SimLab's cloud functionalities to centralize access to PLY files
• Implement collaborative VR review workflows to improve technical communication

These solutions allow companies to fully exploit the potential of PLY files in their engineering processes by overcoming the technical obstacles usually associated with this data format.

Conclusion

The PLY format occupies a strategic position in the CAD interoperability ecosystem, particularly as a gateway between 3D scanning technologies and parametric design environments. Its flexible structure and ability to store rich information make it a valuable tool for many modern engineering workflows.

Optimal exploitation of the PLY format requires a thorough understanding of its technical characteristics as well as the implementation of adapted strategies for its conversion, visualization, and integration into industrial processes. The inherent challenges in using mesh data in a CAD environment can be overcome through proven methods and specialized tools like SimLab.

SimLab solutions offer a complete ecosystem to exploit PLY files to their full potential, from simple visualization to creating immersive experiences in virtual reality. The combination of SimLab Composer, SimLab VR Studio, and SimLab VR Viewer enables transforming 3D scanning data into interactive resources exploitable by different company departments, thus promoting collaboration and innovation.

For companies seeking to improve their CAD interoperability involving PLY files, adopting integrated solutions covering the entire lifecycle of 3D data represents a strategic approach. These technologies not only solve immediate technical problems but also establish solid foundations for future innovation in a context where 3D scanning and virtual reality play an increasing role.

We invite you to explore our solutions dedicated to CAD data interoperability and mesh format management like PLY in more detail. Our experts can accompany you in developing optimized workflows precisely meeting your specific needs and the requirements of your industry sector.

• CADfix
• SimLab

Table of Contents

• Fundamentals of XGL format and its role in the CAD interoperability ecosystem
• Technical architecture of XGL format and advantages for 3D visualization
• Comparison between XGL and other interoperability formats: advantages and limitations
• Software solutions and practical workflows for XGL files management
• Industrial use cases and best practices for implementation
• FAQ on XGL interoperability
• Conclusion

In an increasingly digitized industrial environment, the smooth exchange of 3D data between different CAD systems represents a major technical challenge. The XGL format represents a specialized solution for the visualization and sharing of complex 3D models across various platforms. This guide explores how XGL fits into an effective CAD interoperability strategy, particularly in contexts where precise and lightweight visual representation of technical data is paramount.

Fundamentals of XGL format and its role in the CAD interoperability ecosystem

The XGL format (eXtensible Graphics Language) was developed to address a specific need in the CAD interoperability ecosystem: to provide a lightweight yet faithful representation of 3D models for visualization and integration with modern graphics technologies.

Origin and positioning of XGL in CAD interoperability

XGL originated from industrial needs for efficient visualization of complex CAD data. Initially developed as a visual representation format, it works primarily with triangular meshes (tessellation) rather than exact B-rep representations used by STEP or other standard exchange formats.

• Specialized format for 3D visualization of technical data
• Based on a tessellated representation of 3D models
• Compatible with OpenGL rendering technologies
• Designed for integration into lightweight visualization applications

The uniqueness of XGL lies in its ability to preserve assembly hierarchy while optimizing data for fast visualization. Unlike generalist exchange formats like STEP that prioritize geometric precision, XGL emphasizes rendering efficiency and file lightness.

XGL's place in a 3D data conversion strategy

XGL occupies a strategic position in the CAD interoperability ecosystem, complementary to the main exchange formats. It typically comes into play when visualization and visual sharing become priorities over exact geometric precision.

• Intermediate format in multi-CAD conversion chains
• Solution for creating lightweight visualizations from complex native models
• Alternative to proprietary visualization formats for third-party applications
• Support for visual representation in validation and review processes

In a global CAD interoperability strategy, XGL therefore constitutes an important link for workflows where rapid visualization and accessibility of 3D data are essential, while complementing more precise exchange formats like STEP for exact geometry.

Technical architecture of XGL format and advantages for 3D visualization

The XGL format presents a technical architecture that distinguishes it from other exchange formats and explains its particular effectiveness for visualizing complex CAD models.

Structure and XML syntax of the XGL format

The fundamental strength of XGL comes from its structure based on XML 1.0, which gives it several advantages:

• Human-readable text format and easily machine-analyzable
• Natural hierarchical structure that reflects that of CAD assemblies
• Tag-based referencing system that avoids data duplication
• Ability to store metadata and attributes alongside geometry

The XML syntax also allows the format to be extended to integrate new functionalities without compromising backward compatibility, a major advantage for the long-term technological evolution of CAD interoperability solutions.

3D data representation in XGL

XGL uses a visualization-optimized approach that focuses on the essential elements for efficient rendering:

• Triangular meshes to represent surfaces (tessellation)
• Vertex normals for realistic lighting rendering
• UV texture coordinates for texture application
• Object hierarchy preserving the structure of assemblies
• Color information and visual appearance of components

This visualization-oriented representation facilitates integration with modern 3D rendering technologies, particularly with OpenGL, while maintaining a reasonable file size even for complex assemblies.

ZGL format: the compressed version for optimizing performance

For particularly voluminous models, XGL offers a compressed variant called ZGL:

• Compression of XML data to drastically reduce file sizes
• Preservation of all the functionalities of the standard XGL format
• Improved loading and rendering performance for large assemblies
• Preferred option for network sharing or cloud-based collaboration

ZGL compression represents a major asset for companies managing complex assemblies, allowing for significant reduction in loading times and bandwidth consumption when sharing models.

Comparison between XGL and other interoperability formats: advantages and limitations

To determine when to use XGL in a CAD interoperability strategy, it is essential to understand its strengths and weaknesses compared to other standard formats on the market.

Comparative analysis of technical exchange formats

This comparison highlights the specialization of the XGL format for visualization workflows, complementing formats more oriented towards geometric precision like STEP.

Distinctive advantages of the XGL format

XGL presents several assets that make it particularly relevant in certain CAD interoperability contexts:

• Simplified integration with OpenGL rendering engines
• Easily analyzable and extensible XML structure
• Optimized visualization performance even for large assemblies
• Preservation of complex assembly hierarchies
• Effective compromise between visual quality and file size
• Native management of visual attributes (colors, textures)

These advantages make XGL a format of choice for lightweight visualization applications, collaborative design reviews, and integration into third-party applications.

Limitations to consider in an interoperability strategy

Like any specialized format, XGL presents certain limitations that should be taken into account:

• Loss of geometric precision due to tessellation
• No support for PMI (Product Manufacturing Information)
• Lack of advanced geometric editing capabilities
• Impossibility to define non-uniform scaling
• Mandatory conversion to triangles, even for flat surfaces
• Lack of support for certain advanced CAD attributes

These limitations explain why XGL is generally part of a broader CAD interoperability strategy, complementing other formats such as STEP for exact geometry exchange or JT for cases requiring both visualization and precision.

Software solutions and practical workflows for XGL files management

Effective exploitation of the XGL format in a CAD interoperability environment requires specialized tools. CAD Interop offers high-performance solutions to fully leverage this format in your technical workflows.

SimLab: creating immersive experiences from XGL models

SimLab distinguishes itself as a complete solution for transforming XGL data into interactive and immersive visual experiences:

• Native and optimized import of XGL/ZGL files
• Creation of interactive visualizations from complex CAD models
• Generation of technical animations and assembly/disassembly sequences
• Support for virtual and augmented reality environments
• Technical presentation tools for design reviews
• Generation of interactive visual documentation

SimLab allows you to fully leverage the visual potential of XGL files by transforming complex technical data into interactive experiences accessible to both technical teams and non-specialists.

CADfix VIZ: repairing and simplifying XGL data

CADfix VIZ offers advanced capabilities for preparing and optimizing XGL data:

• Repair of defective meshes resulting from problematic conversions
• Intelligent simplification of models to reduce complexity
• Tessellation optimization to balance precision and performance
• Geometric healing tools to correct conversion artifacts
• Fusion and segmentation of components to restructure models
• Generation of optimized XGL/ZGL files for different use cases

Thanks to CADfix VIZ, companies can overcome common challenges related to the quality and complexity of XGL data, ensuring optimal models for visualization and integration into third-party applications.

Practical workflows for integrating XGL into the CAD ecosystem

Effective exploitation of the XGL format generally fits into structured CAD interoperability workflows:

1. Extraction of data from native CAD formats (CATIA, NX, SolidWorks)
2. Conversion and optimization to XGL format using CADfix VIZ
3. Validation of mesh quality and correction if necessary
4. Adaptive simplification for specific visualization needs
5. Integration into visualization platforms or immersive experiences via SimLab
6. Controlled distribution to stakeholders for review and collaboration

This methodical approach ensures a smooth transition from complex CAD data to XGL representations optimized for visualization and technical collaboration needs.

Industrial use cases and best practices for implementation

The XGL format finds its place in many industrial contexts where efficient visualization of CAD models is essential. Here's how different sectors benefit from this technology and the associated best practices.

Sectoral applications of XGL in CAD interoperability

The unique characteristics of the XGL format make it particularly suitable for certain industrial sectors:

Automotive industry:

• Lightweight visualization of large assemblies for design reviews
• Secure sharing of visual data with subcontractors
• Generation of digital mockups for visual validation

Aerospace:

• Interactive technical documentation for maintenance
• Operator training on complex equipment
• Collaborative design review between remote sites

Industrial equipment:

• Creation of interactive technical catalogs
• Visual support for installation teams
• Generation of animated assembly procedures

Architecture and construction:

• Integration of technical components in BIM visualizations
• Visual review of MEP systems (Mechanical, Electrical, Plumbing)
• Technical communication with construction teams

In each of these contexts, XGL helps overcome CAD interoperability challenges by providing an effective and accessible visual representation of technical data.

Best practices for optimizing XGL files

To maximize the benefits of the XGL format, several best practices deserve to be implemented:

• Adapt the level of tessellation according to final use (precision vs performance)
• Use ZGL compression for voluminous assemblies
• Hierarchically structure files to facilitate navigation
• Standardize component naming conventions
• Apply intelligent simplification techniques for non-critical parts
• Retain essential metadata during conversions
• Implement a quality validation process after conversion

These practices ensure optimal XGL files in terms of performance, precision, and usability in the CAD interoperability ecosystem.

Integration of XGL in a global PLM strategy

For maximum efficiency, the use of XGL must be part of a coherent PLM (Product Lifecycle Management) strategy:

• Positioning of XGL as a visualization format complementary to exchange formats
• Automation of conversion and validation processes via CADfix VIZ
• Traceability of conversions and link with CAD source models
• Integration with document management systems
• Synchronization of revisions between native models and XGL representations
• Clear definition of XGL data access and usage workflows

This integrated approach allows for fully exploiting the advantages of the XGL format while maintaining the consistency of technical data across the enterprise.

FAQ on XGL interoperability

How to integrate XGL files into our existing PLM system?

The integration of XGL files into an existing PLM system typically requires three key components: a converter capable of generating XGL files from your native CAD formats (such as CADfix VIZ), a metadata management system to maintain links between source files and XGL, and finally an XGL-compatible visualization solution. The ideal is to set up an automated workflow that generates and updates XGL representations whenever a source model is modified, thus ensuring data consistency in the PLM ecosystem.

What is the fundamental difference between XGL and exchange formats like STEP?

The main difference lies in the objective and geometric representation. STEP (ISO 10303) is a standardized format designed for precise B-rep geometry exchange between CAD systems, preserving parametric information and mathematical precision of surfaces. XGL, on the other hand, uses a tessellated representation (triangular mesh) optimized for rapid visualization rather than precise editing. STEP is therefore preferred for exact technical exchange, while XGL excels in lightweight visualization workflows and integration with graphic applications.

How to optimize loading performance of voluminous XGL files?

To significantly improve the loading performance of voluminous XGL files, several approaches are recommended. First, favor the compressed ZGL format which considerably reduces file sizes. Use CADfix VIZ to intelligently simplify non-critical geometries while preserving important details. Hierarchically structure your assemblies to allow progressive loading. Finally, consider using Level-of-Detail (LOD) techniques that dynamically adapt the complexity of displayed models according to the visualization context.

Why use XGL rather than other 3D visualization formats?

XGL offers several distinctive advantages compared to other visualization formats: its XML structure is easily analyzable and extensible; its native compatibility with OpenGL facilitates integration into various applications; its ability to preserve the hierarchy of complex assemblies is superior to that of many competing formats; it offers an excellent compromise between visual quality and file size. Moreover, with tools like SimLab and CADfix VIZ, the XGL ecosystem benefits from professional solutions for data creation, optimization, and exploitation.

How to ensure the quality of XGL models after conversion from native formats?

Quality validation of post-conversion XGL models is a critical step that can be systematized. CADfix VIZ offers diagnostic and automatic repair tools to identify and correct common problems such as missing faces, inverted normals, or degenerate triangles. Establish a standardized quality checklist including visual verification of critical components, validation of assembly hierarchy, and metric comparison with the source model. For critical workflows, implement a cross-validation process where XGL models are compared to originals to ensure representation fidelity.

Conclusion

The adoption of the XGL format in a CAD interoperability strategy represents a pragmatic and effective approach to address the challenges of visualization and sharing of complex technical data. Complementing precise geometric exchange formats like STEP, XGL offers an optimized solution for visual representation of 3D models across different platforms and applications.

The solutions distributed by CAD Interop, particularly SimLab for creating immersive experiences and CADfix VIZ for optimizing XGL data, constitute a complete technical ecosystem allowing to fully exploit the potential of this format. These tools naturally integrate into modern engineering workflows where efficient visualization and collaboration around CAD models become critical success factors.

For companies facing the challenges of multi-CAD interoperability, XGL represents a strategic piece of the puzzle, particularly suited to contexts where visual communication of technical data is paramount. By adopting the best practices presented in this guide and leveraging specialized solutions like SimLab and CADfix VIZ, organizations can significantly improve their capabilities for sharing, visualizing, and validating complex 3D models.

The constant evolution of CAD visualization and interoperability technologies will continue to enrich the XGL ecosystem, further strengthening its position as a format of choice for technical visualization and 3D collaboration in an increasingly digitized and distributed industrial environment.

• CADfix
• 3DViewStation
• SimLab

The exchange of technical data between different CAD systems represents a constant challenge for industrial companies. The VRML format (Virtual Reality Modeling Language), although old, continues to play an important role as a gateway between computer-aided design and immersive applications. In a context where digital continuity is essential, mastering VRML interoperability helps optimize workflows and fully exploit the potential of 3D models across different platforms.

Table of contents

1. Fundamentals and characteristics of VRML for CAD interoperability
2. Multi-CAD compatibility and VRML software ecosystem
3. Translation and validation solutions for VRML data integrity
4. Practical applications of VRML in industrial virtual reality
5. Best practices and optimization for VRML data exchange

Fundamentals and characteristics of VRML for CAD interoperability

VRML represents one of the first standards developed specifically for the representation of interactive 3D virtual environments. Standardized under ISO/IEC 14772-2, this format has evolved since its first version in 1995 to meet the growing needs for visualization and interaction with complex 3D models.

Origin and evolution of the VRML standard

VRML was initially designed as a solution for sharing 3D scenes on the internet, before evolving towards more robust industrial applications. Its nature as an open international standard has made it a preferred format for exchanging technical data between different platforms. Today, although superseded by X3D (its successor) for certain web applications, VRML remains relevant in industrial ecosystems for its simplicity and extended compatibility.

VRML files come with the .wrl extension (or .wrz for compressed versions) and use a text-based structure based on nodes, facilitating the hierarchical description of 3D objects. This architecture allows for the representation of:

• 3D geometries (primitives and complex meshes)
• Materials and textures
• Light sources and lighting effects
• Animations and interactive behaviors
• Hypertext links to other resources

Key technical characteristics for interoperability

The VRML format is distinguished by several characteristics that make it a valuable tool for the interoperability of technical data:

• Hierarchical data structure allowing logical organization of complex models
• Support for metadata to preserve design information
• Accessible text format allowing manual editing if necessary
• Support for animations and interactive behaviors
• Ability to represent multi-object scenes with precise spatial organization
• Preservation of visual properties (colors, textures, materials)

As a geometric representation format, VRML primarily uses meshing techniques rather than B-rep (Boundary Representation) representations used in native CAD systems. This feature facilitates lightweight visualization but can result in certain limitations in terms of precision for demanding engineering applications.

Multi-CAD compatibility and VRML software ecosystem

The adoption of VRML in the CAD ecosystem is explained by its ability to serve as a neutral exchange format between different design platforms. Most major CAD systems now offer export functionality to this format, thus facilitating the sharing of 3D models intended for visualization or immersive applications.

The table below presents a summary of VRML capabilities for the five main CAD systems on the market:

This native integration in major CAD systems allows engineers to quickly share models intended for visualization without requiring access to native CAD software, thus facilitating interdisciplinary collaboration. Export options are generally accessible via standard export menus, with various parameterization possibilities to balance visual quality and performance.

For cases requiring more sophisticated conversion, specialized tools like 3DViewStation offer advanced capabilities allowing not only visualization of VRML files, but also bidirectional conversion between VRML and various native or neutral CAD formats, with more precise control over conversion parameters.

Positioning in the exchange format ecosystem

VRML fits into a broader ecosystem of exchange and visualization formats, where it occupies a specific position oriented towards interactive visual representation. The comparative table below helps situate VRML in relation to other standard formats commonly used in industry:

This complementarity with other standard formats enables the establishment of processing chains adapted to different industrial needs. Each format presents specific advantages depending on the context of use:

• STEP remains the reference for precise exchange of engineering data, particularly suitable for CAD/CAM/CAE applications requiring exact geometry and complete product information.
• JT has established itself as a high-performance lightweight visualization format in industrial environments, with the ability to represent both exact geometry (B-rep) and simplified representations, while supporting PMI (Product Manufacturing Information).
• 3D PDF excels in technical documentation and extended communication thanks to its wide distribution and capabilities for integrating multimedia documents.
• STL, a format historically linked to additive manufacturing, offers a simplified but effective representation for certain production processes.
• VRML stands out for its native ability to represent interactive environments, making it a relevant choice for web visualization and virtual reality applications.

The choice between these different formats therefore depends on the specific needs of the project: geometric precision, visualization performance, need for interactivity, or integration into documentary systems. In many cases, companies use several formats in parallel, converting data according to the needs of different stages of the product lifecycle, with tools such as 3DViewStation or CADfix VIZ to ensure the necessary conversions between these formats.

VRML viewers and manipulation tools

The software ecosystem around VRML includes various tools for visualizing and manipulating these files:

• Web browsers with specific plugins (historically)
• Dedicated desktop applications for industrial visualization
• Integration into PLM platforms for lifecycle management
• Conversion solutions for translation to other formats
• Geometric analysis and validation tools

This technical ecosystem facilitates the use of VRML as a link in the industrial digital chain, from design to the final user experience.

Translation and validation solutions for VRML data integrity

The conversion and validation of VRML data constitute critical steps to ensure the integrity of models throughout their digital lifecycle. CAD Interop offers several specialized solutions to address these interoperability challenges.

3DViewStation: high-performance visualization and conversion of VRML models

3DViewStation represents a complete solution for the visualization and analysis of VRML models in an industrial context. This powerful tool offers extended capabilities for working with VRML files:

• High-performance visualization of complex VRML models
• Detailed analysis of components and their hierarchy
• Precise measurement and dynamic dimensioning of geometric elements
• Creation of sections and exploded views for technical analysis
• Export to VRML format from other CAD formats

One of the distinctive features of 3DViewStation is its ability to convert native CAD models to VRML format while preserving:

• The hierarchical structure of assemblies
• Visual properties (colors, textures, materials)
• Metadata essential to understanding the model
• Geometric precision necessary for technical visualization

This dual capability of visualization and conversion makes 3DViewStation a versatile tool in the technical data processing chain, particularly suitable for companies working in a multi-CAD environment.

CADfix VIZ: repair and geometric optimization of VRML data

VRML models resulting from conversions from native CAD systems may present various geometric imperfections affecting their use. CADfix VIZ addresses this issue by offering advanced repair and simplification functionalities:

• Automatic diagnosis of geometric errors in VRML files
• Repair of mesh defects (missing faces, intersections, etc.)
• Geometric healing to ensure model watertightness
• Intelligent simplification to reduce model complexity
• Mesh optimization for improved performance

The simplification capabilities of CADfix VIZ are particularly relevant in the context of VRML, allowing:

• Reduction of the number of polygons while preserving essential characteristics
• Adaptation of the level of detail according to the requirements of the target application
• Balancing visual fidelity and display performance
• Preparing models for resource-constrained environments

These features make CADfix VIZ an essential link to ensure the usability of VRML models in various application contexts, from web visualization to virtual reality.

SimLab: creation of immersive experiences from VRML models

SimLab distinguishes itself by its ability to transform VRML models into interactive immersive experiences, thus bridging the gap between technical data and advanced user experience applications. This solution allows:

• Importing VRML files while preserving their structure
• Enriching models with advanced interactive behaviors
• Creating animations and simulations based on technical models
• Developing AR/VR experiences accessible on various platforms
• Generating virtual tours and interactive technical presentations

SimLab excels in transforming VRML data into true technical communication tools by:

• Adding intuitive user interaction mechanisms
• Integrating contextual information into 3D models
• Creating training and learning scenarios based on models
• Generating applications deployable on web, mobile, or VR headsets

This solution significantly extends the scope of VRML models beyond simple visualization, creating true business applications with high added value.

Practical applications of VRML in industrial virtual reality

The VRML format, despite having several decades of existence, continues to play a significant role in many industrial sectors as a bridge between traditional CAD and modern immersive applications.

VRML as a gateway between CAD and immersive environments

One of the main strengths of VRML lies in its ability to serve as an intermediary between precise but heavy design environments and immersive applications requiring optimal performance. This strategic position allows:

• Extracting visual information from CAD models without their parametric constraints
• Maintaining a faithful but lightweight representation of technical designs
• Facilitating deployment on resource-limited platforms
• Providing access to models without expensive CAD licenses

This feature is particularly valued in several concrete industrial scenarios:

• Collaborative design reviews involving stakeholders without CAD expertise
• Technical training based on interaction with 3D models
• Commercial presentations of complex technical solutions
• Interactive technical documentation accessible via web browsers

Industrial use cases of VRML

In the industrial sector, several concrete applications demonstrate the continued relevance of the VRML format:

Collaborative design review

VRML models facilitate design review sessions between multidisciplinary teams. A manufacturer of industrial equipment uses this approach to enable engineers, designers, and customers to collaborate effectively, even when they don't have the same CAD tools. The lightweight nature of VRML files also allows remote reviews via secure web platforms.

Technical training and interactive documentation

The industrial maintenance sector exploits VRML models to develop immersive training modules. These simulations allow technicians to virtually explore complex equipment, practice specific maintenance procedures, and access contextual documentation, all without risk to the actual equipment.

Factory layout simulation

Industrial facility planning also benefits from the use of VRML models for:

• Visualizing the spatial arrangement of equipment and production lines
• Simulating workflows and identifying potential bottlenecks
• Validating workstation ergonomics before implementation
• Effectively communicating layout plans to different stakeholders

These applications illustrate how VRML can be used as a vector of innovation, transforming complex technical data into accessible decision-making tools.

Best practices and optimization for VRML data exchange

To get the most out of the VRML format in a CAD interoperability context, several good practices can be adopted to optimize the quality and usability of models.

How to effectively prepare your CAD models for VRML export?

The quality of a VRML file begins with adequate preparation of the model in the source CAD system. To optimize this process:

• Simplify non-essential geometries before export
• Remove invisible internal components that unnecessarily increase the model size
• Organize the assembly structure in a logical and hierarchical manner
• Clearly define visual properties (colors, textures) in the source model
• Validate geometric integrity before export to avoid propagation of errors

Export parameters also play a crucial role in the quality of the result:

• Adjust mesh precision according to intended use (finer for engineering, coarser for web visualization)
• Activate compression option (.wrz) to reduce the size of voluminous files
• Preserve assembly hierarchy during export to facilitate navigation
• Include relevant metadata to maintain model traceability
• Test different parameters to find the best balance between quality and performance

Simplification techniques to optimize performance

Geometric simplification represents an essential aspect of optimizing VRML models, particularly for immersive or web applications:

• Selective polygon reduction on low curvature areas
• Intelligent decimation preserving sharp edges and important features
• Removal of details below a determined visibility threshold
• Merging of adjacent elements sharing the same material properties
• Optimization of normals and UV coordinates to maintain visual appearance

Tools like CADfix VIZ offer sophisticated algorithms allowing this simplification while preserving the visual and functional integrity of models.

Optimal structuring of VRML data to facilitate reuse

The internal organization of VRML files greatly influences their usability in different application contexts:

• Use explicit names for nodes to facilitate their identification
• Group components logically according to their function or relationship
• Separate geometry and appearance to allow independent modifications
• Integrate predefined viewpoints to guide initial visualization
• Structure animations according to a logical sequence if applicable

This organization facilitates not only navigation in complex models, but also their reuse in different contexts such as technical documentation, training, or commercial presentations.

Why validate the quality of VRML models after conversion?

Post-conversion validation constitutes an often neglected but essential step to ensure the integrity of VRML data:

• Verify geometric accuracy compared to the source model
• Check the preservation of hierarchy and assembly structure
• Validate the preservation of visual properties and materials
• Test display performance on target platforms
• Ensure that all interactive functionalities work as expected

Tools like 3DViewStation facilitate this validation by allowing direct comparison between source models and generated VRML files.

Conclusion

CAD interoperability of the VRML format continues to represent a strategic issue for industrial companies seeking to maximize the value of their technical data. Throughout this guide, we have explored the fundamentals of this standardized format, its software ecosystem, specialized solutions for its manipulation, its concrete applications, as well as best practices to optimize its use.

The VRML format, despite the emergence of new standards, retains its relevance as an effective gateway between traditional CAD environments and modern immersive applications. Its ability to represent complex 3D models in an accessible format and its extended compatibility with the multi-CAD ecosystem make it a valuable tool for visualization and technical communication.

The solutions distributed by CAD Interop - 3DViewStation, CADfix VIZ, and SimLab - offer a complete set of tools to fully leverage the potential of VRML in your business processes. From high-performance visualization to the creation of immersive experiences, through geometric repair and optimization, these solutions address the different interoperability challenges that industrial organizations may encounter.

To remain competitive in a constantly evolving digital environment, companies must adopt robust interoperability strategies, where VRML can play a significant role as a link in an integrated digital chain. Implementing the best practices presented in this guide will optimize the quality and usability of your VRML data, thus contributing to more effective collaboration and better valorization of your digital assets.