Hello list,

I'm not sure I understood openscad's "check validity" feature
correctly, so I thought I'd be asking about it here.
The output I'm getting for [0] is this:

ERROR:
CGAL error in CGAL_Nef_polyhedron3():
CGAL ERROR: assertion violation!
Expr: e->incident_sface() != SFace_const_handle()
File: /usr/include/CGAL/Nef_S2/SM_const_decorator.h
Line: 326
Valid: no

The main reason I'm asking is that the error message doesn't seem to
have anything to do with whatever form of geometric analysis of the
shape in question is done.

cheers!
mar77i

[0] https://gist.github.com/mar77i/c97245aa3ecc87a0000da569e02988cf

Martin,

This could be related to wrong winding order of the manually created polyhedron.
See https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/FAQ#Why_is_my_model_showing_up_with_F5_but_not_F6.3F

-Marius

It appears that was indeed the problem. Thanks a lot for your assistance.

cheers!
mar77i