Groove constraint for 2D physics. Groove constraint for 2D physics. This is useful for making a body "slide" through a segment placed in another. Set the final offset of the groove on body A. Return the length of the groove. Set the initial offset of the groove on body A. Set the length of the groove. The body B's initial anchor position defined by the joint's origin and a local offset [member initial_offset] along the joint's y axis (along the groove). Default value: [code]25[/code] The groove's length. The groove is from the joint's origin towards [member length] along the joint's local y axis. Default value: [code]50[/code]