You can get the current UE4 flex to hold the soft body deformation. You just set particle velocity to zero. I don’t know what plastic deformation looks with flex. But was my first attempt at soft body collision using the zero particle velocity. watch?v=jhE_WlNhPps
Besides the current UE4 Flex missing the plastic deformation, it’s also missing the diffuse particles. Without the diffuse particles, all fluids look like jelly. Also Unity recently got Flex support as a plugin. Not sure how difficult it is, but hopefully UE4 will get the different gameworks as plugins in the future. Also it would be great to get the cpu/non-cuda version of Waveworks.