Hi all, I am really trying to end this thread, but it keeps growing. Crob: When I import assemblies from other softwares which were already created, they come without any mate. many times I just move, rotate, study and modify as necessary in SW. In those situations, I prefer to rotate the part I am interested in XY,YZ or ZX co-ordinate to see the relative positions. so, I pick any center line of radius or circle and do the rotation (I can do this in IDEAS for example). In this situation, I know with which centerline and angle i should be rotating the part with. But, if I were to use mates, i have to make sure I make it right. I have not fully understood how to use mates, but when I tried to rotate using two temporary axis, i wanted it to rotate in XY but it did in YZ (for example). I think still have problems. I will investigate more this week. EEND: I use mates for simulating motions, but, I have one problem with that when I have forces at an angle. I will post a separate thread for that after some more trials. Thanks all.