I have a model that has been modeled & rigged in Maya, whenever i export it as an FBX and take it into unity it seems to collapse at certain areas (see the attachments for a before and after). The model is fine when brought into unity in the T position but once I give a pose in maya & get it to unity it seems to collapse in certain areas. I’ve even tried importing FBX file into 3ds max , model seems to have no problem in it. Its only when I import into unity I seem to get this problem.
I would go back and and check all of your topology, if you have any faces that are open or any floating vertices, it may do strange stuff to your model. An easy way to check it is to throw it into 3DS Max and run STL Check. It will show you where all of the potential mistakes are.