[OpenSCAD] simple test case: CGAL error in CGA_Nef_polyhedron3(): CGAL ERROR: assertion violation

Marius Kintel marius at kintel.net
Mon Oct 31 11:38:45 CET 2011


On Oct 31, 2011, at 04:50 AM, Michael Brown wrote:

> I was trying to make a printing plate to speed up printing 4 LM8UU bearing holders for the Prusa I am building. I downloaded the STL from http://www.thingiverse.com/thing:8900, and made a simple openscad file to print out two at a time:
> 
Ouch.
This is a long-standing issue and has been reported numerous times.
Unfortunately, the STL import pipeline in OpenSCAD is extremely sensitive, to the point where exported files sometime cannot be imported.
I fear this requires a fair bit of work to fix, and it's one of the things I'd like to do after the current development version is out the door.

For other devs out there:  I believe this has something to do with an internal optimization gone wrong (using a grid to merge vertices in close proximity, causing a non-manifold topology on imported 3D models).

 -Marius



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