Animation Tutorial - Reactor

3DStudio Max comes with a built in physics engine called Reactor (developed by Havok) which can add gravity, friction and collisions to objects in a scene.

The first step is adding the objects you want to be affected by Reactor to a Rigid Body collection. Other collections exist such as the soft body collection (in which objects compress and morph when colliding with other objects) and cloth collection which can realistically animate cloth based objects.

When using reactor there are a number of different variables which can be changed to modify how an object is affected. The collision tollerence determines at what distance a collision will take place. Gravity can be set on any axis with the z-axis set to -386 by default. Each object also has Mass, friction and Elasticity sliders to determine how it behaves.

Using these tools on the bowling alley objects provided for the tutorial I created a realistic looking strike animation.

 

In this scene I set the alley floor to have a mass of 0 so that it is not affected by gravity while giving the ball a mass of 20 and the pins a mass of 5. Mass is effectively proportionate to weight so the higher the mass the heavier the object. I set the collision tollerence to about 0.5 over 3.6 to make the bowl more realistic. 

Finally to give the ball momentum I moved the ball forward along the alley by about 5 frames and adjusted reactor to only take effect from frame 2. I also lowered to ball to just above the surface of the alley floor and added a spin to the ball.