STEP AP242 Standard

The standard STEP AP 242 (ISO 10303 AP242) “Managed model based 3D engineering" is the merging of  2 ISO standards:

  • Aerospace's STEP AP203 "Configuration controlled 3D design"
  • and Automotive's STEP AP214 "Core data for automotive mechanical design processes"

STEP AP242 capabilities


  • Exact shape representation, which is use in the current CAD tool implementing in STEP AP214 and STEP AP203
  • Tessellated shape representation. This representation is new in STEP. It allows display efficiently the 3D shape by using a simplified representation (example: triangulated faces).


  • Graphic presentation : The advantages of graphical Presentation are that since it is rendered, it is presented in the STEP file exactly as it was in the CAD system. Since the instantiation is done using basic geometric entities, basically every viewer or CAD system which finds the link in the file structure can display it. The PMI is stored in STEP using geometric entities:
    • polylines (points, curves,...) , already use in STEP AP214
    • or tessellated , new in AP242
  • Semantic representation: Geometric Dimension and Tolerance are stored in the STEP file in parametric. After exchange, it allows the interpretation and the modification like in the native CAD system.


  • Assembly and Part geometries in the same file
  • Assembly with expternal reference to 3D geometry file (in STEP or other format)
  • Nested assembly