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CGAL error, performing boolean ops on imported meshes and primitives #220

ghost opened this Issue Nov 24, 2012 · 3 comments


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ghost commented Nov 24, 2012

Not sure if this is a known issue and referenced in a more technical bug report, but I'll submit this anyway since I can't see anything like it.

Using the following simple code, I'm able to generate this error message:

CGAL error in CGAL_Nef_polyhedron3(): CGAL ERROR: assertion violation!
Expr: pe_prev->is_border() || !internal::Plane_constructor::get_plane(pe_prev->facet(),pe_prev->facet()->plane()).is_degenerate()
File: /media/code/mingw-cross-env/usr/lib/gcc/i686-pc-mingw32/4.6.2/../../../../i686-pc-mingw32/include/CGAL/Nef_3/polyhedron_3_to_nef_3.h

    #translate([38,16,5]) cube([5,2,45]);   

The code references an STL file downloaded here: http://www.thingiverse.com/thing:19590

Also worth noting, the regular F5 renderer also doesn't display properly, showing a bunch of projected white holes. I've been doing a lot of CSG against imported STL files lately and while it never seems to look right pressing F5, I've been able to count on it working when pressing F6.

Tested in Latest release and Latest Snapshot for Windows


kintel commented Nov 25, 2012

Thanks for the report. The STL import of more complex parts is indeed very fragile. We've had a lot of bug reports related to this and it's something we'd like to fix.

Btw., I managed to get your model to work by importing it into Meshlab and running a slight simplification on it (which would remove the smallest details, which is likely to trigger issues in OpenSCAD).


ghost commented Nov 25, 2012

I see, sorry for the dupe bug, and thanks a bunch of the Meshlab tip, I hadn't considered changing the imported model!


kintel commented Jan 22, 2015

Closing as duplicate of #945

@kintel kintel closed this Jan 22, 2015

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