Dear Nuno, There are tutorials for animation on thr PTC support web site. Basicaly you have to assemble your model in a slightly different way. The first component in the assembly has to be constrained in the default location because this then becomes the ground member and cannot move with respect to earth. Instead of using normal align, mate, etc constraints, you have to use proper mechanical constraints like pin & cylinder etc. For example when you assemble say a second component you may want to use the pin option, this constrains the axis and a face, allowing only one freedom- 'rotation'. I think you should find a tutorial. If you fail to find one, perhaps it will be a good idea to model a very simple crank assembly and practice on this so that you get to know the concept. After this the next step is to start the 'mechanism' application and apply motors to drive the assembly and capture the animation. It will be a steep learning curve without a tutorial. Hope this helps, Mike
