The built in dynamics engine of 3ds Max does not support an automatic center of mass calculation. In fact, it is the task of the user to build a center of mass with the help of dummy mass objects. Usually this is work for an apprentice, not for a high class effects animator!
Why would I need that?
The center of mass is vital for proper and believable dynamic simulations. A wrong placed center of mass point can easily destroy the look of a simulation. Imagine a classic "standup toy" that always returns to its upright position. A heavy lead weight in the bottom center of that toy makes it always stand up. thinkingParticles comes with an advanced automatic center of mass algorithm that will calculate this important point within a 3D geometry. No user interaction is necessary for this task. A virtual "stand up" object will properly wiggle around until it comes to an upright rest. In many situations this feature alone is a lifesaver!
For Digital Dimension, a well known visual effects (VFX) house based in Canada, thinkingParticles came to the rescue for their "Blade III Trinity" project. A bunch of vampires had to be sent back to their graves and this had to be done in the most impressive way. The "ashing" sequences were generated with thinkingParticles`new physics engine. Vampires break into a thousand pieces and fade to dust - a classic effect! With the introduction of rule based dynamics, Digital Dimension went, in a single step, further than all such visual effects created before Blade I or Blade II. Breaking bones is a bit tricky, as there are a lot of them and it is not defined how they are formed or where their center of mass will be. And as everyone knows, there are a lot of bones to break and shatter in a vampires' skeleton. No matter how Digital Dimension vaporized the vampires, the remaining bones tumbled and bounced off of each other, nicely and believably.