Hi Flywaver :) I personally can't tell you about the DEM files as I've never used them. You can hide things that you don't want to render for test renders...just go into your render options. There are choices that allow you to render all, selected objects, etc. It may be best to put all the things that you don't want to render on a separate layer, then make the layer that does have the objects you want to render the active one and set your render options to render only the active layer. There is also a way to clone vegetation (or anything else for that matter)under Edit/Duplicate. Make sure your object is selected first. If you want to make fields of grass or lots of trees, use Edit/Scatter Objects. Place 4 different vegetations at four corners encompassing the area you want to fill. Select them all, then choose Edit/Scatter Objects. Enter how many copies you want and you will wind up with lots of plants :). You may just want to purchase the Vue 4 manual as Vue 4 is a major upgrade to Vue 3 :). I hope this helps a little, and someone will come along who can answer your DEM question :). Laurie