Ossim is a simulation baking tool. It allows you to generate an armature and skinned geometry based on physics simulation to use in game engines and realtime applications such as Unreal Engine 4 or Unity3d or any other realtime application that supports animated armatures.
Geometry for simulations can be made in a lot of ways. There’s built in addon for Blender called CellFracture.
There is also external addon called PhysAssist.
Or you can bring it from other 3d software.
Generated armature in Blender:
Result exported to UE4: