clear3d( ... )
rgl.clear( type = "shapes" )
pop3d( ... )
rgl.pop( type = "shapes" )clear3d and rgl.clear clear the specified stack, while rgl.pop removes
the top-most (last added) node on the stack.
Since the bounding box is an optional element, one can disable it
with clear3d.rgl
rgl.bbox
rgl.light