To answer Genny yes they do BUT to do it in real world scale (sorry Im a Surveyor..cant help myself LOL) as Jay said is a pain in the coight. I have adopted doms suggestion ages ago and 'pretend' 1 unit is 1 metre even though the grid is set to centremetres...and yes Jay the render times etc increas...why is that??? For finnicky work or to get it damn close Gen I use the 1 unit rule and sometimes break the subs up to get what I want ie. 5 subs = 0.2 increments and so on. This way I can get it really close...painful stuff but thats Maya..LOL

For me Sirwalrus if I couldnt find actual dimensions (there will be some somewhere trust me) then I would take an image like this one...standard modern doors are approx 2.1 m in height (in the old days maybe less as they werent as tall as we are today). So I would use a rule (scale rule if you have one)...determine the height of the door in this image and come up with a scale based on the door. Al you have to do then is make your buildings on a bit of guess work and physically measuring the areas you want...I will post shortly what I come up with and you will be able to apply this to ANY image...as long as you have a rough idea of dimensions.

cheers bullet