I'm doing the Spitfire tutorial and I'm at a point where I seperated the wing from the body by deleting faces. The geometry is still whole. Now I check Sub-D to make sure model alligns to the image plane. But the change to Sub-D causes delete.

delete |polySurface2|polySurfaceShape6;

I went back to before I deleted the faces and it changes to Sub-D but the verticies are unselectable.

I don't know if the problem is what I'm doing in the model or is something screwed up in my settings.

Thanks for any help.