Hey Chip, 

First off, What a great tool you have created here.  Congratulations.  Could you let us know what atmosphere you used in the tutorial?  I noted in the documentation you mentioned that you changed atmosphere so the spacefreame could be more easily viewed but you never said what change you made.  Was it just a color change to the sky color from the basic modelling atmosphere you created in your other tutorial and if so, what was the RGB values?