In addition to constraining two or more rigid bodies, you can also constrain a single active rigid body to a global position in space. You can either pick a spot in global space or use the rigid body's center as the constraint position.
To constrain a single rigid body to a point in space
Choose any of the three following workflows:
Choose a constraint from the Create Rigid Body Rigid Constraint menu in the Simulate toolbar: Hinge, Ball and Socket, Spring, Slider, or Fixed. The constraint object is created.
Left-click the spot where you want the constraint to be positioned — the constraint object goes there.
Left or middle-click to pick the active rigid body. The constraint object is attached to this object's center.
Choose a constraint from the Create Rigid Body Rigid Constraint menu.
The constraint object is created at the position of the rigid body's center.