Myles - thank you. Its interesting/encouraging (to me) that one can use Sketchup to create the actual 3-D drawing. I should quickly note that looking at the pictures of the diesel engines and the wheel lathe shown earlier, you've got some serious 3-D computer modeling chops - that's not easy in any rendering environment. One thing I've discovered about Sketchup is the 3-D model warehouse where you can often find models that are 'good places to start'. Still, Sketchup has a pretty non-linear learning curve - some parts are easy and some are more like steep cliffs... (that I keep falling off if I haven't used that particular skill in a while...)
You mention 1 inch rendered in O-scale (= 1/48") is about the smallest free-standing objects that aren't too fragile. Just to turn that question around a bit -- what's the smallest object or feature in the 1:1 world you think is worth 3-D printing in the scale world - just in terms of having an adequately detailed model? You noted in one of your pictures that there was a missing mounting bolt on the wheel lathe - which I'd guess in the real world is probably a couple of inches or more. Do you try to render features (into O-scale) that are smaller than an inch? You indicate you can print at a 10 micron resolution (which scaled up from O-scale to 1:1 is ~1/64") - a level of detail that I think even the most ardent rivet-counter would ignore...
Your work is really quite amazing.
