Calculation torque on arbitrary point

Mojtaba

Hi everybody. I've simulated motion of a rigid body (solid structure) in fluid stream. I've performed this in two-way FSI manner (CFX and Workbench together). I've encountered a problem in post processing in CFX-POST. How can I calculate the torque on arbitrary point? In other word I want to calculate torque on a certain point attached to a certain node which moves? Do I have to do anything in CFX-PRE before run my simulation? For example define a local coordinate system? I didn't succeed in define a local coordinate system which its origin attached to the certain node. Thank a lot.