Rigid bodies

User Guide > Dynamics and Effects > Dynamics > Soft and Rigid Bodies >

Rigid bodies

A rigid body is a polygonal or NURBS surface converted to an unyielding shape. Unlike conventional surfaces, rigid bodies collide rather than pass through each other during animation. To animate rigid body motion, you use fields, keys, expressions, rigid body constraints, or collisions with particles.

Maya has two kinds of rigid bodies—active and passive. An active rigid body reacts to dynamics—fields, collisions, and springs—not to keys. A passive rigid body can have active rigid bodies collide with it. You can key its Translate and Rotate attributes, but dynamics have no effect on it.

For instance, to bounce a ball on a floor, you would make the ball an active rigid body because it needs to fall with gravity and rebound after colliding with the floor. You would make the floor a passive rigid body so it doesn’t careen away from the ball when the ball bounces off it.

Dynamic animation of rigid bodies is controlled by a Maya component called a rigid body solver. Dynamic animation of rigid bodies is motion created by fields and collisions.

Note

You can create only one rigid body per object or object group.
Only one side of a rigid body surface can collide—the side with normals facing outward. Error messages occur if rigid bodies penetrate each other.
Do not animate the scale or other deformations of a rigid body.
A curve cannot be a rigid body.
A subdivision surface cannot be a rigid body.
You can make a rigid body collide inside another. Place the object inside the other object, reverse the normals or surface of the outer object, then animate the inner object in an outward direction.
When you key a passive rigid body’s Translate and Rotate attributes, the Time Slider doesn’t show key markers. Use the Graph Editor to see the keys. You cannot remove keys on these attributes with the usual techniques. See Warning when you delete rigid body connections.
With rigid bodies, avoid using the Edit > Duplicate menu item with Duplicate Input Connections or Duplicate Input Graph. Use the Dynamics Relationship Editor to connect the duplicate rigid body and fields.