Physics-Simulation for gravity and collision-detection.

Many 3D packages provide physics-simulators, to make animator's live much easier and to make some realistic 3D-animations possible which weren't without them. If dozends of cubes, for example, in "Impact 4" are flying through the air, colliding, turning, free falling and bouncing off, normally one should wink off, to much effort.

Thanks to physiks modules you only have to define mass, elasticity and friction, the rest is done by the program. You can see it in "Impact 4" in the "Animations" Gallery.