Thanks for the info Mike. I tried out 3Dem and it is fast and works with both the old style USGS DEM's and the new standard of SDTS. It doesn't write USGS DEM format output, but you create a binary terrain matrix. I load that into Wilbur (did I put the link up for that!) and save the image out as a true-height field for Vue4. By the way, is there a limit to how big an image map can be used in Vue4?