I am currently working with a model of a folding door and I am using linear motors to pull the door open and then reverse directions and close. I am in SW2008 SP3. The problem I have is everytime I exit SW (or it does it for me, as it crashes often) and I reopen SW and the file, the Motion Study cannot solve. If it moves at all it locks at the reverse. I have been using 2 motors, 1 up 1 down, the up turns off at the halfway point and the down turns on at the same point. I can't change the assembly any really, my supervisor (not a SW user, more an advertiser) doesn't want it any different. I've been using Cosmos Motion and rendering through PhotoWorks. Is this a common problem? I know Solidworks is not meant as an animator, but I need to find a way to make it work!