CGAL users discussion list

[Marius Kintel <>]

Hi all,

Consider the two attached objects (a cube and a smaller cube).
I want to subtract the smaller cube from the larger one and export to OFF.
For demonstration purposes, this can be done using the Polyhedron_3 demo 
which ships with CGAL:
o Add each file, convert each object to Nef, subtract, convert back to 
Polyhedron and finally save as OFF

The issue: The saved OFF file has the inside walls facing the wrong way: It 
is saved as one positive cube inside another positive cube.

This issue was discovered in OpenSCAD, a 3D modeling tool using CGAL, and a 
detailed discussion about why we think this may be a CGAL bug can be found 
here:
https://github.com/openscad/openscad/issues/495

Any ideas?

Cheers,

 -Marius

Attachment: cube10.off
Description: Binary data

Attachment: cube5.off
Description: Binary data