The first four segments are done.
I'm not happy with the engineering. Basically, I had no real sense of the shape and how it would work (as in, how best to hook them together, how best to be self-supporting, how to mold, whether they would be stackable) until I'd built the masters, and at that point I was loathe to take the time to strike off in new directions.
Which means what I ended up with is casting the side pieces with a supporting ledge, and with both that ledge and the deck pieces having holes sized for the smallest readily available (aka could be bought by the packet at my local hardware store) supermagnet.
The ledge didn't mold well, and the material of the master wasn't well-suited for holes, so the magnets don't fit that well. And they sort of stick out, too. Which along with the ledge makes the things stack quite badly. And superglue is not as strong as supermagnet; it is unfortunately easy to tear a magnet out when dissembling a road segment.
I'm still not sure which alternatives would be strong enough to support themselves safely enough to permit figure miniatures to be placed on top. I think based on my Holocron experiments that snap-fit acrylic might be stable enough. It would be even better if I could design some simple bracing scheme. And I have a feeling I could come up with a way to transfer the detailed texture of the master to vacuum-formed shells that could then be glued to acrylic backing.
If someone asked for a lot more of these things, I'd definitely experiment. As it was, I made about two dozen casting attempts over most of a week just to achieve four complete sets. And painting, as crude as it was, took another three or four days.
When I have some fresh casting compound I'll try to run off a couple more. I'm also still planning to try to make both an access ramp and a tower, both of which it is my intention to make a simple shell mold and slush-cast (the poor man's roto-cast) in one piece. No more fumbling with magnets. Might also desire some of the pillar elements which are used in conjunction -- these I am assuming I can model and 3d-print easier than anything else (although possibly cast instead of wasting the print time making more than one).
Yeah; basically, the lesson of the raygun strikes home; I would have done better making a full CAD aka 3d model first. And possibly printed the master. Pity it seems so difficult to transfer out from CAD to a good EPS file for laser cutting. Working it out in 3d allows you to visualize, and get all the dimensions, and makes it a lot easier to make changes as your design evolves. It does take longer to start with, but the time-savings only get larger as you get further and further into the design and build cycle.