seems mesh combine is not working like it should?
deleted one surface from a mesh. rebuilt it, and did a combine.
The result is a fairly smooth mesh ( you can still see the face patched into the surface a bit)
Converting to nurbs ignores the combine command as it seems.

I've made some changes in the next build to help prevent this from happening. The combine does not flip normals so one set of facets was flipped. Until you get the update, do a show normals before you combine to make sure everything is pointing outwards.

Tim