This is a simple alias to rgl::aspect3d(1).
This is typically used to rescale data in different units, for example
longitude and latitude in degrees and elevation in metres.
Note that running rgl::aspect3d("iso")
which show the realistic ratio of
the plot axes, ignoring units. Running this function is equivalent to
rgl::aspectd(1)
(or rgl::aspect(x = 1, y = 1, z = 1)
) which sets the
apparent ratios of the current bounding box.