[rowe]

you have to use reactor, but you already knew that. to set up the process, you must first add a ridgid body collection to the scene, under the modify tab, add the objects you want to be simulated, including stationary objects. u may choose to add a reactor plane to the scene, but having a regular plane added to the ridgid body collection works well too. after you have added all the objects, go the utility tab and select reactor. under properties there should be a mass input box. 0 kgs is the default setting and indicates that the object is stationary. for concave objects, you will be required to use to change simulation geometry. once you have all this, go to hte preveiw & animation menu and hit create animation.