[OpenSCAD] avoiding assertion violation

nop head nop.head at gmail.com
Wed Jul 17 03:40:06 EDT 2019


Yes that sounds right. Each bit that touches the y axis can't be a single
point because that creates a singularity when rotated.

The zero thickness knife edge at the bottom is dodgy as well. Any CGAL
operations near that point are likely to create self intersections.

Both features are psychically impossible.

On Wed, 17 Jul 2019 at 07:43, MichaelAtOz <oz.at.michael at gmail.com> wrote:

> Ronaldo wrote
> > In the limit case, when just a simple polygon vertex is on the Y axis,
> > there is no smartness to avoid non-manifoldness and an error might be
> > issued.
> >
> > However, when, the polygon is not simple, like in the example bellow, it
> > is
> > harder to detect beforehand a non-manifoldness of rotate_extrude():
> >
> > rotate_extrude(){
> >   polygon([ [2,2],[3,3], [2,4] ]);
> >   translate([1,0]) square(2);
> > }
> > cube();
>
> So a test would be if polygon vertex.x=0 then at least one adjacent vertex
> must have x=0 & a different y.
>
>
>
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