thanks for you help
my latest problem is that i can just about create a DTM now, but it is superseeded in the air. i have downloaded the pdf help and printed it out, and it shows on the cover a golf hole. i understand the basics about how to create it now, but the hole show a terrain like i have done, but it starts at ground level. the way that i tried to do it was to set my locus points where i wanted them, and duplicate them in exactly the same position and set them to 0 height.
IT DOESNT WORK!!
please help...........