Hello Flywaver and welcome! As for DEM's, I've used them a few times, and yes they do work pretty well. I don't know much about the diferent kinds of DEM's so without any more info I don't know what to say other than what SMT and Varian have said. If you're having a problem with one or more, maybe you could direct me to a URL to find one and I can have a look at it? Good first picture. Soon you'll see just HOW much Vue is capable of. :) Cheers, Mike