It seems everytime I try to fix something here I break something else, but anyway, another try at getting this to work properly. Fixes for: - Getting dupliverts/faces derivedmesh with orco caused wrong results on meshes in linked dupligroups with proxy, because modifier stack was revaluated with wrong object matrix, now gets orco another way. - Fix render instances being hidden when original object was not added to the object render list. - Changed the way object instances find their original objects, now works the other way around, original objects look for their instances instead. There's probably issues still with recursive dupligroups..