This happens only in the preview Fire Fly setting. When you go to do your final render and set your Fire Fly render to "final" it should capture the whole picture in the background. If you do a test render in P4 I think you'll find the background filled as well. This occured in P5 so I suspect it happens in P6 too. Back face polygons are not calculated in the final render. Polygons that do not face the camera. If you ever want to see the polygons, switch your figure to "wire" mode and you will see hundreds of them. By not calculating those polygons it speeds up renders times. I can't help you with your other questions.