I have split a solid body along a curve into the 2 parts, then done all sorts of work to the parts to hollow them out (one is just a shell, the other is quite a bit more involved.
Anyway. how do I mate them back together again in the final assembly? It greys them all out when I select the edges, the surfaces, or anything that I would expect to go together on the 2 parts. I need to line up some screw holes between the 2 parts that I cant do pre-split since it has to go thru the stuff thats going inside the bottom half of the item.