I need to create an effect in maya where a billiard cue hits a ball, and the motion of the movement causes the other balls to hit each other and simulate the opening break of a game of 9 ball. I had no problem creating the balls and cues, and giving them the proper passive/ active bodies. I could not however get the motion of the cue right. I tried using uniform or radial motions to make the cue strike the ball, but it would keep moving forward even once it struck the cue ball. Is there a way to make it stop or reverse direction once it makes contact. Or is there an easier way to do this entirely?
I would definitely recommend making the cue stick a passive rigid body, not an active one. Then you can animate it by keyframe exactly how you want.
Also note that objects can be keyframed between being passive and active--but only in the channel box, not the Attribute editor (the 'Active' attribute shows up as a check box in the AE, which cannot be keyed). If a passive rigid body is moving while it gets changed into an active one, its velocity will be preserved and used to start its active dynamic simulation, which makes it possible to "throw" objects, among other things.
Also you might need to check the rigidbody attributes, mass, bounciness, friction etc, that's where the magic happens running the sym alone doesn't work like you need almost NEVER :D ,
the secret to syms is, TWEAK IT TWEAK IT and TWEAK IT again,
also as Steve said, you don't have to rely only on sym, you can get in there and TWEAK IT so it does what you need