See3d.be always most helpful.
In that case you need to go back to your modeling package and apply a different color/material to the walls you want different colors. You can not seperate surface in Lumion. Importing is based on the materials assigned.-------FB http://www.facebook.com/Lumion.be
Make a simple single color texture in your favorite photo editing software.Any color you want. Make it as small in size as possible (less memory it takes off your graphics card).Save it as a .jpeg (or whatever file format you prefer) - smaller the better.Use it in the custom material slot. Adjust as needed with the sliders.Add normal/bump texture for surface irregularities if warranted.I'll try to throw some of my own up here in a few hours.