Believe it or not, this started as a cube in topmod. Extruding, smoothing and converting the mesh to "columns" were some of the important steps. The building is composed of about six layers - from the inside out, there is a glass copy with a smaller negative glass copy hollowing out the inside. That's enclosing a solid steel copy with 40 negative floors slicing it vertically. Around the outside are the "columns" made from the original mesh edges, in steel. Inside are two stacks of 40 lights, and a few more surround the outside to eliminate the deep shadows. I find that smooth curved boolean meshes made of glass bring out the worst rendering performance in Bryce. At 1600x1200, this took about 60 hours. I don't know exactly since it finished while I was out shopping this morning. When I was setting it up, I hid the glass and it was going to take about 6 hours, so that hints at the impact. But, it looked too naked without the glass! It really could use some trees, but I would bet it might double the render time again.