Some good suggestions, thank you all very much. I will try following up to see what works best in my situation, although I feel I will end up with a laser level and quite a few batens hammered into the ground to pick up levels from.

What you are looking for are DEMs. Digital elevation models. Most cities have ones created be synthetic aperture radar, accuracy about 1 meter, or lidar, accuracy about 1 foot. Rural areas are a lot more variable. The shuttle flew a mission that did SAR from orbit, but the grid spacing is about 30 meters, and the accuracy is awful.

If USGS topo data is good enough, I vaguely recall a page on converting topo lines to terrain. Warning: topo data is not very good at the house lot size level. There is typically a semi-systematic error in the horizontal placement of contour lines equal to several times the contour interval. The shape is right, but slope inflections tend to be moved away from the centre of the photographic track.

If its critical to get it right, rent a DGPS, and take a waypoint every 10 meters. If the terrain isn't too bad, you can do a hectare an hour.

Gees, you guys are helpful! I really do appreciate all of your comments and advice. Credit where credit is due Mr. Sonder, they are really useful videos and some beautiful models and drawings. I'd be printing and framing some of those bad boys to put up on show!
I've used SU to produce some simple schemes in my day job (Mechanical Engineer) which I then export out as an iges for our draughtsmen to import into our CAD system. it works ok, except import exporting from different versions (I have to import as an STL and export as an iges). My point being is that I have used it to a basic level and am starting to understand how/when to apply groups and components and to setup scenes. I guess i'm trying to think ahead and get my structure in place first before I draw anything, so your comments and advice are helping to clear things up in this respect.

Chri's suggestions are sound, but it doesn't get over the 'labeling' issue...
If you give the components names relating to part-refs then when you manually add a Text object pointing to one of them then by default it should show its name as the initial text-string ?
It would be possible to code something to add text at every instance with its definition name etc, but try it manually first off...

The first time I hooked up an external monitor, I had the same trouble, I couldn't drag anything left to right from my lap top to the secondary. Then realized I had my laptop on the left and the secondary on the right, but in the control panel, I didn't notice that I had my secondary monitor on the left side and laptop on the right. Just identify and make sure they are oriented to match the 1--2 on the monitors and the control panel. Sounds elementary but sometimes the best answers to frustrating issues are the most obvious.

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