2009

Properties rollout
Parent When on, the constraint has two bodies and you can designate an
object to be the parent body. When off, the constraint is single-bodied and
the point occupied by the Parent Space sub-object is the parent.
You assign the parent object by clicking this button and then selecting a rigid
body from any viewport. Thereafter the button displays the name of the parent
body.
3998 | Chapter 16 reactor