Thanks for that, very helpful.
The horizontal weatherboarding lines were done in a hurry and some ended up stood off the surface by an inch in the plane of the window frames rather than on the surface of the walls. Could to better if I tried.
I didn't know about front and back surfaces so thanks for that. I've been looking for a problem with the materials or something like that to explain the colour difference!
Yes I built it slightly oddly. Basically I built a plain box then fitted an oak frame the same size into it so there will be coincident faces and lines that aren't merged properly. That's ok for my purposes.
I'm doing ths model because I need to get approval from my local council to build it. They only want 50:1 elevation drawings and an isometric sketch to approve the appearance. Sketchup's sketchy line styles will be great for the isometric. Once the basic style is approved I'll probably go back to an earlier version which has the frame seperate to help with the design of that. Currently the roof has no structure.
Regards,
Colin