ahhh you might be really on to something here!

I forgot that I can SET the worldPoint property!! That is definitely how I'm gona have to iterate through the points, but the problem, as you say is how to figure out which points it would have used in during the rendering, but I think samplerInfo may have more useful properties for determining that.

I'll play with it in the morning and let you know.

Thanks for the help - i'll let you know what i find.

David