0030024: Data Exchange - STEP, IGES export support of BRep shapes based on tessellate...

0030024: Data Exchange - STEP, IGES export support of BRep shapes based on tessellated geometry

Support of reading and writing tessellated geometry is added for the following STEP entities:
- triangulated face
- complex triangulated face
- tessellated shell
- tessellated solid
- tessellated shape representation

Models without BRep geometry (mesh formats like STL, OBJ and so on) are supported for writing to STEP.

New parameters are added to enable/disable tessellated geometry reading and writing:
- read.step.tessellated (On/Off/OnNoBRep) (On by default)
- write.step.tessellated (On/Off/OnNoBRep) (OnNoBRep by default)

OnNoBRep - tessellation is read/written only for entities for which there is no BRep representation.

Faces with poly triangulation are written in STEP as triangulated face entities with one coordinates list per face.
Only one poly triangulation per face (returned by BRep_Tool::Triangulation) is written to STEP.