We are having a discussion (arguement actually) here about the best way to properly simulate a part that moves on rollers. With 4 pins through the part, one on each corner (pins that hold rollers) what is the best way to constrain them in simulation so that they are free to move along a plane? With several of the available methods that we have used it seems that the constraints keep the C/L distance of the pins constant which gives inaccurate results. The frame should be allowed to flex and the rollers follow but remain planar. I think there are ways in beam mesh but we need to do this in a solid mesh.