Jean - thankyou that's a nice way to go about it.
Zapwizard - that's a good suggestion using TIG's drape control points plug in - I'll experiment a bit with this. I had a very quick look at Artisan, but need to research it a bit more... but from what I can see, it is possible to manually add or simply detail in the mesh. It would be good however if there was a tool that could analyse the vertical complexity in the xyz data so that points that were similar to their neighbours would be tagged as redundant, so that an optimal irregular mesh could developed. Does such a plug in exist? Does Artisan do this?
Thanks for your replies so far
Mick