3D interoperability around Virtual Reality and Augmented Reality software OpenSceneGraph

OpenSceneGraph is an open source 3D engine that is widely used in the development of visualization and graphics simulation tools. It is entirely programmed in C++ and built around OpenGL, which allows it to run on a wide variety of systems such as IRIX, Linux, FreeBSD, Mac OS X, Windows, etc.

History of OpenSceneGraph The OpenSceneGraph project was launched in 1998 by Don Burns, who then created his own company while continuing to participate in the project. Robert Osfield joined the team in 1999. In September of the same year, the source code for OpenSceneGraph was made public under the terms of the LGPL license.

Uses of OpenSceneGraph OpenSceneGraph is widely used in the field of graphic visualization, 3D simulations, and virtual reality. It is also used for creating video games, although this is not its primary target. OpenSceneGraph has all the necessary features to create complex 3D scenes, such as simulation 3D models (flight, marine, vehicle, space simulator), virtual reality or augmented reality, medical and scientific visualization, education, and games.

Supported File Extensions and Formats The *.osg file extension is used to store scenes created with OpenSceneGraph. These files contain information about 3D models, textures, lights, and cameras, as well as the scene configuration. OpenSceneGraph supports the import and export of many file formats, including COLLADA, OpenFlight, 3D Studio, and VRML. This allows users to work with 3D models created in other software such as SketchUp, Maya, and Blender, and use them in their own OpenSceneGraph application.

osgconv: 3D File Conversion Utility osgconv is a utility program that allows you to read 3D databases, apply basic operations, and save them as a single 3D database. osgconv can be very useful for reading standard 3D formats such as OpenFlight, 3DS, Alias Wavefront (OBJ), etc., and converting them into a supported OSG native format, such as the ascii .osg format or the binary .ive format. By default, the loaded scene graph optimization will be performed so that the resulting scene graph written is smaller and faster to use during execution, and the .ive file format is particularly fast to load, making it ideal for database storage and large databases.

Texture Conversion Texture conversion is another important aspect when converting files from different formats to OpenSceneGraph format. When converting files such as .IVE that contain integrated texture image files to formats such as .OSG that do not, the resulting database may not display textures. The .OSG file format supports the "OutputTextureFiles" option, which allows it to generate new external texture image files.

The texture files will be generated using the original texture file name still present in the scene, and will use the format suggested by the file name extension. This is only possible if the destination directory specified for the texture file already exists.

Some combinations of formats and texture data are not compatible, for example, the .RGB format is not capable of storing compressed texture data. This means that if you started with a scene using external .RGB texture images, converted to .IVE, and compressed your texture data since the conversion to IVE, converting to .OSG with external .RGB texture files will not be successful. See also: http://forum.openscenegraph.org/viewtopic.php?t=3196&view=next

Texture compression and decompression during the conversion process are performed by the OpenGL implementation, not by an OSG software algorithm. This means that driver defects may manifest at this stage. Issues with corrupted textures can be caused by a defective OpenGL driver.

CAD Interop distributes several software for preparing, viewing and converting OpenSceneGraph files. Find below the list of our solutions compatible with the OpenSceneGraph format: