I have a mechanism which I am attempting to animate. It involves animating two angle constraints as well as enabling and disabling other constraints at the proper times. When I run the animation for the first time it runs properly. If I leave the repeat button depressed and the animation runs several times it has slight variations which build up to parts displacing to areas on the screen which may be perhaps correct in a geometric solution but not the ones I started out or the ones I want and eventually the computer locks up. Thanks for any suggestions.