CUDA Particle simulations

Hi,
I was trying to interface haptic devices in CUDA particle simulations, so I have to update proxy position, as well as transfer the processed forces to the proxy.
The CUDA kernel calculates the forces and updates all the position and velocities of all the particles as a system, which is not easily accessible from the main program.
Any ideas how can I get Collider force in the program, so that I can transfer it to the proxy.

Thanks
Dwai

PhysX in UE4 does not use CUDA