Hi Heiner, the "create planar face" function will only work if the curves you give it are both closed and planar, you need both of these conditions to be true not just being closed alone. Polygons in OBJ files are not restricted to only be planar, so most likely the ones that are not working for you have some slight warping to them and are not totally flat polygons. It's not that unusual for quads in polygon mesh files to not be totally planar.

Typically it just does not work very well to try and convert a complex high density polygon mesh file into a NURBS object by making one little individual surface for each source polygon, it looks like that's what you're trying to do here...


> Even stranger: When i isolate one of these closed curves (the objects in
> question get listed as closed curves) and then try to draw another curve or such,
> the snaping function ignores it. In other words: surrounding
> objects get recognized by snap and the cursor snaps to them, these curves not!

Could you export some of these unsnappable objects to a small example file and then attach the file here so I can take a look?

- Michael