Working roof for extension

[cyclonebri1]

Hi,
I'm trying to get a bit of advice before planning on how the roof of an proposed extension would work.

I don't think I could describe effectivly in words the layout, so is there anyway someone can point me in the direction of something I post up here and show my plan.

It's simply the roof not the interna/plan.

 

[RedHerring2]

A photograph, with explanation,
Googlesketchup
Paint
Paintshop pro
Excel

 

[^woody^]

Google Sketchup

Draw your cuboids for the main building and extension, then draw your triangles or pyramids for the roofs, and then extend the extension roof into the main roof