Calcite area type needed

I'm drawing a cave with large areas of calcite in it. Some way of drawing these areas is needed. Ideally such areas should have some kind of 'direction' or 'contour' info as they are not uniform. Any ideas how we might best implement that? Wookey -- Aleph One Ltd, Bottisham, CAMBRIDGE, CB5 9BA, UK Tel +44 (0) 1223 811679 work: http://www.aleph1.co.uk/ play: http://www.chaos.org.uk/~wookey/