And I've now got the grid correctly mapped with the correct alpha, in this case I'm using a .png to drive the alpha channel.  And I've managed a nice little demo animation - just to see what the model looks like with the grid opening.

Thanks for all the help on this.

Measure your mind's height
by the shade it casts.
Robert Browning (Paracelsus)

Fran's Freestuff

http://franontheedge.blogspot.com/

http://www.FranOnTheEdge.com