Hi Rich,

re:
> Is there any way to scale it proportionally about a known dimensional reference (to get an
> image to roughly match it's real world dimensions - say by clicking on one point on a plan,
> and another and having the image scale to meet it)

Yes, that's what the "Align" button in the View > Image command does. That lets you pick 2 points on the image as the reference, then 2 points in model space for how to map the image line into model space.

It will move, rotate, and scale the image so that the image reference line matches the model space line.

Demos here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=1982.9
http://moi3d.com/forum/index.php?webtag=MOI&msg=2501.14

- Michael