Well, I changed some things around, got rid of a light jib caused by a long fence brush, snapped some things to the grid, and now it's compiling. It's been compiling for about 10 hours, and when I left for work it was at about 92% in the radiosity build. So we'll see how it goes when I get home. What seems new to me is that the visdata size is now only 71,000- about a fourth of what it was before. Is this because of the "-blocksize 0" command? Could you explain what this means in more detail than the advanced compiling tut says?