Hi there, I am using Solidworks Motion analysis to simulate my third year project and I am having some problems with it. I have been teaching myself thus far and have been making good progress with the learning curve, but I have now hit a stumbling block. I am trying to simulate a robot in a pipe which uses passive springs to compress the wheels against the wall of the pipe. With the assembly of the robot on its own, I have been able to simulate the springs easily with the spring tool. However, when I add this assembly to my pipe part and add the springs again, they do now work. Has anyone had this same problem and have a possible solution for me? Any help would be greatly appreciated. Thankyou in advance. Mark.