Florian Brucker <tor### [at] torfboldcom> wrote:
> Nevertheless it's annoying that a degenerate cylinder causes a parse
> time error and not a warning. Degenerate triangles, spheres and boxes do
> not trigger errors (in fact they're not even triggering warnings),
> whereas an empty mesh throws an error, too. Is that really necessary?
> What's the problem with ignoring those objects at parse time?
>

As an additional note, degenerate cylinders are not equal to other
degenerate objects.  Other objects that are degenerate are essentially
objects of 0 dimension in all directions, and will not form a surface of
any sort so the rays can pass by without intersection without deleting the
object.  However, a cylinder can be degenerate in length but not radius.
This would be equivilant to a flat disc with zero thickness which would be
a surface that rays can intersect with.  However with no length vectors,
the orientation of this disc is unknown to POV and the surface intersection
cannot be calculated which can cause a calculation problem.
There may be ways that this can be fixed in a newer version as Thorsten has
pointed out, by automatically deleting the offending object, however in
some instances it may not be desired.


-tgq

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