Simple scene: A cube falls and breaks into pieces when it hits the ground.
For that, I used the Bullet physics integrated into Blender 2.66. I set a cube high above a floor and it falls. I added keyframes on its Animated status checkbox so that I stop it just before it hits the floor. At this point, I animated its position to move it under the floor and, at the same time, I animated all the shards from its fractured copy to replace it.
All the shards also have keyframes on their Animated status checkbox so that physics kicks in only after they are in position above the floor, ready to fall. (BTW, if somebody knows a way to keyframe this checkbox for several objects at the same time instead of having to do them one by one, or a way around, I’m interested.)
That’s the theory… In reality, the shards jump high in the sky and fall back onto the floor where the fractured cube finally explodes. Yes, as weird as it seems, the fractured cube keeps its shape during all its ballistic trip, even without constraints.
Maybe my whole approach is… sub-optimal? Maybe the shards turn into rockets because I animate their position from under the ground and Blender interprets it as an impulsion toward the sky? Or what-not?
Here is the file: RigidBody Test.blend (179 KB)
Thanks for your time…