Constrains an object to a plane that can be defined by any type of object. This is often useful to use for keeping a character on a plane while it's walking or running.
To apply: Select an object, choose Constrain 
Bounding Plane, then pick the object to which the selected object will be constrained.
To redisplay: Select the constrained object, choose Explore Constraints on the MCP, and click the constraint's icon.
For more information, see Bounding Volume and Bounding Plane Constraints [ Animation ].
