play3d() translation

Hi All,

I would like to be able to use play3d() to translate the view along a
surface, and zoom in and out. All the examples in play3d() function
description are of rotations.

I would also like to know if there is a method of creating a legend of for
the 3d surface using rgl package.

You can use any 4x4 matrix you want as a userMatrix setting: see 
?matrices for the list of support functions.  For translations, you'd 
use translate3d instead of rotate3d.

Creating a legend is harder, because it will tend to move as you move 
the surface.  rgl doesn't yet have a way to apply different user 
transformations to different parts of the scene.

Duncan Murdoch