This is just great Chris. Thank you so much.
I deal with many diffrent urban projects and
I clearly see that Skechup with smart programmers like yourself
has great potential in evolving into sth not only for visual outcomes but
for urban analysis.
Color by Z is already a great start isn't it?
Could this kind of approach broadens to....
**- analyze daytime shadow coverage ratio

• density analysis(maybe by comparing # of lines certain area contains)
• open view condition by z**
  and so on and so on...

If anyone is interested, I would love to discuss about it(just can't program it ;( ).
Thanks again Chris.