I converted a 3DS Model (no material or lights) to STL format. I then imported the STL file into SW2005. Everything was fine until I tried to render the model. It just doesn't appear in my render window. I apply a material but it doesn't show up on the render preview screen. I can zoom and rotate the model but simply cant render it. Its as though its not there! How can I remedy this? What am I doing - or not doing?