Rigid bodies Auto Disable flag.
Every body can be enabled or disabled. Enabled bodies participate in the simulation, while disabled bodies are turned off and do not get updated during a simulation step. A disabled body that is connected through a joint to an enabled body will be automatically re-enabled at the next simulation step.
Disabled bodies do not consume CPU time, therefore to speed up the simulation bodies should be disabled when they come to rest. This can be done automatically with the auto-disable feature.
If a body has its auto-disable flag turned on, it will automatically disable itself when:
A body is considered to be idle when the magnitudes of both its linear velocity and angular velocity are below given thresholds.
(Auto Disable parameters)