Gary, I'm quite confident that Pro can do what you want, but I'm not sure what that is. Do you want to create three different versions of your assembly, have one assembly which can be changed to different positional states, or create animation? In the simplest case you could have two parameters, one for the slide, one for the gripper. Setting the values of these parameters would then create the various states you seek, and these could all be preserved in a Family Table. The parameters could be Real Number parameters with numeric values to control position, or Yes-No parameters (say "EXTEND" & "CLOSED") with conditional logic to set the different positional states. David