No David, This is just a diagnostic test that there is something wrong with your video card/driver. You should update your driver to be fully compatible with OpenGL (thus SU) in order to work better on large models as well.

Thanks for the responses everyone. It's given me some ideas to go on, particularly, the idea of making the pyramid, unfold it and then scale it to fit the material. I initially used the dimensions of the sheet of the copper (4',4'), made a square and then pulled it up into a pyramid, then unfolded it and took measurements which were larger than the 4' span. So it didn't compute with me. I actually made it out of copper last night, kind of guessing the angles, and it turned out o.k. My first fabrication attempt of that sort. It's a hood for a forge. It's a truncated pyramidal type thing. It's was a recycled piece of copper and a little beat, but it'll work. I'll reverse engineer it in SU and post it once i figure out how to post something on here. Thanks again everybody