Reactor (Using the havok engine)

The reactor engine is a very powerful function of 3DSmax.
it allows us to animate car crashes, blocks being hit by balls, realistic tablecloths, and water. It is also possible to animate realistic looking ropes, car movements, an object that break into small pieces when hit or dropped.
to create a simple scene in which a ball hits a few blocks, create a plane, then a sphere (which must hover above the plane, not actually touching) and two cubes (once again making sure they do not touch).
rotates the plane slightly so that it slopes downhill towards the boxes.
next go to the animate menu and choose reactor from the bottom. From the reactor menu choose crate object and select rigid body collection. This will then give you a circle with free boxes in it. This is your rigid body collection just move it somewhere safe in your scene.
You'll notice that on clicking any rigid body collection, but information about it has appeared on the right-hand side under the modify tab. you must now select items to be in this rigid body -- Tick the pig button and select your objects alternately click the add button if you have a lot of objects.
It is important that all objects that you wish to be involved with animation in this rigid body collection.
Next return to the reactor menu and this time choose open property editor. Click on your plane firstly give it a mass of Zero and take the inactive box. Also under simulation geometry click concave mesh.
Next click on the sphere, give this a mass of 100, a friction of 0.3 and choose concave mesh once again under simulation geometry. Finally click on each of your boxes and give them a mass of 0.2 and chooses concave mesh again.
Next return to the reactor menu and click preview animation. You should now have a working animation, if not have a look to make sure that you have followed my advice above.
If you have an animation that you're happy with, choose the create animation button. This is an irreversible process to ensure that you have a backup saved before clicking this button.
An example of a working reactor animation is shown below (this also shows part of one of my scenes that I have been creating).