I wondering if its possible for corrective blendshapes to be used I wanted to know before I do all the work then find out its not possible. But if it is possible how does the import process work? Do I just leave it apart of the rig or what. I not very familiar with game engine animation.
I believe what you’re looking for is Morph Targets in UE4. You can read up on them here (which includes information for both Maya and 3DS Max):
We also have a great deal of information on the animation system within UE4 which you can access here:
Hope that helps!