Thanks Peter, I've managed to greatly reduce the processing time now of my simulation which is a relief. I have one further question though.nI would like to constrain my chassis so that it's motion can only travel in the direction of just the wall, i thought by adding a displacement and applying it to the members of the chassis it would work however i receive the error Could not transfer loads and constraints to the solver nAny idea on what i could do to solve this?n