Concepts of Computer Graphics/Output Space/Vectors/STEP

STEP or Standardized Exchange of Product is a CAD/CAM standard used to write out information for interchange by many modeler program like CATIA, PTC's Pro/Engineer, SolidEdge, and SolidWorks.

• 2D used in draft represent a vector layout
  
• 3D Boundary representations (BREP), have 4 major types:
  

1. * I) Wireframe
   

1. * II) Simple
   

1. * III) Facetted representation,
   

1. * IV) Advanced boundary representation .
   

[http://wheger.tripod.com/step/csg.stp CSG Constructive Solid Geometry]

In addition to representing geometry and topology, the format allows for representing additional engineering processes (e.g. stage of the model and annotations). Furthermore, one can write a feature history and associate to the CSG representation, the BREP.