[OpenSCAD] Discuss manifoldness, co-incident faces edges etc

arnholm at arnholm.org arnholm at arnholm.org
Sun Nov 17 02:28:56 EST 2019


On 2019-11-17 00:33, Michael Marx wrote:
> As Doug said 'STL can't represent curved surfaces, it can only
> represent a polyhedral approximation'.

That's true of anything that comes out of OpenSCAD or any other mesh 
based modeller, it is nothing particular to STL, OBJ, OFF, AMF or 
whatever format you choose. A mesh representation is a finite 
approximation, of course it is.

It is not the file format, is the core modeller.

If you took the CGAL library and replaced it with another library based 
on CAD BREP style datastructure, for example OpenCASCADE 
https://dev.opencascade.org/ the situation would be different, and you 
could output STEP files or other formats with accurate respresentation 
of curved geometry. But as long as the core model is a mesh 
representation, the output will be a polyhedral approximation.

Carsten Arnholm



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