exception in polygon.cpp about manifold

[makc]

I assume there is a problem in b's bottom area, where some small triangles seem to sit on top of large ones 🤔 despite this mesh passing manifold test.

[makc]

Looking at it further, it is actually whole 2nd box there:

I guess it boils down to what you said here:

I don't currently make any guarantees about handling self-overlapping input meshes, and I don't have an efficient way to test for them either. I would like to make an algorithm to fix these, but that'll take considerable time. Until then, general input meshes aren't going to be safe.

[elalish]

Indeed, you are correct. I really need at least a decent self-overlap checker method. I might just turn that exception into one that says: "self-overlapping input detected, which is not supported". I only haven't because it's possible it could also be a legit bug, though I haven't found any recently.

[makc]

I guess I will close this one since it has to be fixed on web-ifc side.