Hi Micha,

> (5) mesh #3
>
> I attach the original surface, now it should be buggy. ;)

It looks like this one is due to having a surface that has an internal crease (G1 discontinuity) in it.

This is kind of an unusual surface since you have created a degree 1 surface with a lot of points in it - normally when you have a surface with a lot of points like this, it typically is done as a degree 3 surface so that it will be smooth when you pull points around on it, a degree 1 surface is kind of more similar to a polyline, and typically degree 1 surfaces are used only with a smaller number of points to form a simple plane (using just 4 corner points).

At any rate, the bug in this case is in the splitting function that is supposed to split surfaces at G1 discontinuities when they are loaded, it is only splitting it partially in this case.

I've fixed it up for the next v2 beta, so it will get split properly when loaded and mesh well.

Another workaround for the current release is to use Edit/Separate on it, and then Edit/Join to rejoin it, that will cause it to get split up properly and it will mesh well after that.

- Michael