Set and get the "information" mode of geometry transform g. The mode can be 0 or 1. The default mode is 0. With mode 0, when a transform object is collided with another object (using dCollide (tx_geom,other_geom,...)), the g1 field of the dContactGeom structure is set to the geom that is encapsulated by the transform object. This value of g1 allows the caller to interrogate the type of the geom that is transformed, but it does not allow the caller to determine the position in global coordinates or the associated body, as both of these properties are used differently for encapsulated geoms. With mode 1, the g1 field of the dContactGeom structure is set to the transform object itself. This makes the object appear just like any other kind of geom, as dGeomGetBody will return the attached body, and dGeomGetPosition will return the global position. To get the actual type of the encapsulated geom in this case, dGeomTransformGetGeom must be used.