Hi,

I have created a complex mirrored nurbs object (car body). I then added a floorpan using a nurbs grid and surfsect sop. From the resulting closed shape, I am now trying to subtract a nurbs tube using surfsect (like a wheel arch running across the entire body). The inner half of the tube works fine cutting through the entire floor pan. Unfortunately, it only cuts through one side of the body wall but doesn't for the other (mirrored) half. I think this may be to do with the point normals pointing the wrong way – even though I have selected reverse in the mirror sop. I tried everything and cannot figure out an answer. Any ideas of where I'm going wrong would be gratefully appreciated.

Could you perhaps show us a screenshot of the geometry? It would make it easier to determine what's going wrong.

I think it's important that when you do your surfsect, you don't do it across the seam of your geometry. It seems to give dodgy results for sure.

I'm assuming when it does the cut, if the seam lies across the cut, you'll have three sections instead of two which makes it trickier to determine inside and outside of the cut.
The more pices of geometry you have the more confusing it's likely to get.
Maybe bust it down and cut each part individually.

jerry