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

[Michael Brown]

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:

translate([-6,81,0])
    import(file="LM8UUYHolders.stl");

rotate([0,0,180])
translate([-6,81,0])
    import(file="LM8UUYHolders.stl");


Compiling and rendering the design results in this:

Parsing design (AST generation)...

Compiling design (CSG Tree generation)...

Compilation finished.

Rendering Polygon Mesh using CGAL...

CGAL error in CGA_Nef_polyhedron3(): CGAL ERROR: assertion violation!

Expr: pe_prev->is_border() ||
!internal::Plane_constructor<Plane>::get_plane(pe_prev->facet(),pe_prev->facet()->plane()).is_degenerate()

File: /usr/include/CGAL/Nef_3/polyhedron_3_to_nef_3.h

Line: 252

CGAL Cache insert: import(file="/home/michael_e_brown/thing (0 verts)

CGAL Cache insert: multmatrix([[1,0,0,-6],[0,1,0,81],[0,0,1 (0 verts)

CGAL Cache insert: multmatrix([[-1,-1.22461e-16,0,0],[1.224 (0 verts)

CGAL Cache insert: group(){multmatrix([[1,0,0,-6],[0,1,0,81 (0 verts)

PolySets in cache: 1

Polygons in cache: 900

CGAL Polyhedrons in cache: 4

Vertices in cache: 0

Total rendering time: 0 hours, 0 minutes, 0 seconds

WARNING: No top level geometry to render
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