You can specify the rigid body type by setting Body Type in the Create Rigid Body Option window or in the Rigid Body Properties section of the bulletRigidBodyShape node Attribute Editor. In Bullet, Dynamic rigid bodies are often referred to as active rigid bodies while Kinematic and Static rigid bodies are also known as passive rigid bodies.
There are three types of Bullet rigid bodies:
- Dynamic rigid bodies (Body Type > Dynamic Rigid Body) are fully simulated physics objects. This type is the most performance intensive rigid body. By default, all rigid bodies are created as Dynamic rigid bodies.
- Kinematic rigid bodies (Body Type > Kinematic Rigid Body) can be animated during the physics simulation, but they are not affected by the simulation itself. Because kinematic bodies can be moved, the Bullet physics simulation spends more time updating kinematic rigid bodies than static rigid bodies.
- Static rigid bodies (Body Type > Static Body) do not move during the physics simulation. The Bullet physics simulation can optimize how it updates static rigid bodies in the scene since it knows their positions remain fixed between frames.
You can animate the rigid body type and its transformation. When the Body Type attribute is set to Kinematic Rigid Body, you can set keys for the rigid body's Transform attributes. Keyed transformations have no effect when Body Type is set to Dynamic Rigid Body. Dynamic rigid body transformations are determined by the solver. See Rigid Body Properties for more information about Rigid Body settings.