Maya allows you to "Lock" Normals in the Direction they are currently in - so when you move Vertices around they still stay as they were when they were locked - until you unlock them again. So you could try going along the "Cut Lines" and locking the Vertex Normals there, then detach the respective parts.
Well as Cheese said, this SHOULD be something handled by the programmers... Pose/morph targets should only store vertex information for vertices that change position. Try to press them a bit more or maybe even postpone a solution... pipeline for something like this is going to be a bitch, likely... Anyway, in 3dsMax, you…
It's not easy rooster.You can use "average normals" across multiple objects, but it locks the normal in world space so goes FUBARed when you move the model. A better approach (and I think Source uses this) would be to keep the model intact, and only store the info for any verts that have moved. So when storing the morph…
We did it on a bunch of bond games ( http://www.daz-art.com/games_8.htm ), but it's not ideal. As others have said, it isn't too much effort on the code side to just store the verts that transform. The 'faceplate' system worked OK for us, but its clearly much more of a headache than not. One thing that really irked me is…