#Suggestions
Uh, have you read the documention? Axis is very clearly described.
The flic was smaller when you made the walls solid because the wireframe
walls caused more deltas than the plain, solid, surface. Plus, your matte
material didn't have a highlight, and you probably weren't dithering the
output. Both of those things contribute to very small delta updates.
Rendering time is more affected by the number of pixels the objects are
occupying, rather than the total number of objects (unless you've got a
HUGE number of objects, or lots of transparent objects in front of each
other).
– G