want to know about " Rigid Body Joint " Constraint....

hi !

blender animators, 
           i am looking for <b>Rigid body Joint</b> constraint. 
"<b>http://wiki.blender.org/index.php/Manual/Constraints/Rigid_Body_Joint</b>" in this page there was nothing, this page may be under constraction....:no: 
 i want to know <b>what is the job of this constraint and how i use this</b> ????.....:eyebrowlift:

The Rigid body Joint constraint is a Game Engine/Physics Engine constraint and not one designed to be used for keyframed animation . It adds (just as its name suggests) “rigid” joints to objects in/during the GE/Physics Sim like jointed figures or rotating parts like wheels or water/wind mills etc . The last Rube Goldberg contest using Blender’s GE/Physics Engine had a lot of examples using this constraint … I personally have no experience with this yet … you might want to post this question on the GE section of the forum for more educated explanations …