Sentinels Tactics: Building up the Terrain

There's a project going on right at the Sentinels Tactics forums on creating 3-D terrain for the game. The approach is to print intricate designs on card stock that can then be cut up, folded, and glued and taped together. Some of the preview shots look pretty good:
Unfortunately, I'm not going to be able to capitalize on this work, for three reasons:

1. I am terrible at cutting up, folding, and gluing cardstock shapes in such a way that they don't immediately spring apart and have to get taped down.
2. I know from previous experience that even if I could make decent cardstock buildings, after I toss them in a box and drive them to the game store on the other side of town a couple of times, they're going to be crumpled ruins.
3. I'm worried that the very tall buildings will make it hard to see the miniatures on the table, especially for shorter people sitting on the far side of the table. This came up with some props I put together for a previous supers RPG game, where I discovered that 40mm high walls are way too tall to use with 28mm tall miniatures.

So I need an alternate way to get 3D buildings that will create much, much sturdier props, and preferably flatter ones that won't block visibility so much.

Fortunately, I have something like 15 square feet of black foam core lying around the house from a previous project. Small buildings of foam core are a bit of pain to cut out, but once glued together they're fairly resistant to damage and easy to repair.

The following shots are mostly a proof of concept, but I'm already liking the effect:

That's the Freedom Tower in 3D, with Beacon, Mr. Chomps, and Unity menacing the Operative.

Construction was pretty simple, though tedious and involved:

1. Photocopy a hex tile 4 times in black and white. These are just going to be used as cutting guides, so they can be on cheap paper and in a low ink mode.
2. Trim the photocopies to 7.5" squares, along one of the long axis of the hex tile.
3. Lightly glue the photocopies in a line along a sheet of foam core.
4. Cut the photocopy covered section of foam core away from the rest. There's now a piece that is 7.5" by 30", and it's not exactly convenient to use but it's better than a huge sheet of foam core.
5. Take a bunch of the hex tiles from Sentinels Tactics and find all the elevated terrain on them. Take a pencil and match similar patterns of hexes on the photocopies. Try to maximize coverage and use all the hexes.
6. Go over the final collections of hexagons with a sharpie or other thick pen.
7. Cut out the patterns with an exacto knife. This is enormously tedious, and requires a knowledge of how to cut foam core, which can be found on the web. After cutting a pattern free, pull off the black and white photocopy sheet
8. Photocopy the hex tiles in color this time. These copies are going on top of the final hex patterns, so they need to be of reasonable quality.
9. Cut out the final color hexes and glue them to the patterns, gluing the patterns to each other as necessary.

One 30" by 7.5" section produced enough hex patterns to almost cover the entirety of the Megapolis side of the Tactics hex tiles. I'm hoping that another section will handle the rest and the Insula Primalis terrain, but I might have to do a total of three sections.

Edit: It took two sections, plus some miscellaneous scrap to build up the Insula Primalis volcano. Which is still not working out as well as I'd like.

Completed Megalopolis pictures!

And on the flip-side of the tiles, Insula Primalis (tile 7 is completely flat for Insula Primalis, so I didn't do anything with it). Visionary faces off against the Operative on the rim of the central volcano.

If I had a better workshop at home, I'd have considered doing these in a light wood (balsa?) and cutting them with a jig. I think I could have gotten the angles a little more precise with that kind of set-up.

Another possibility would be to use a 3-D printer, but that's not something I own (yet). This seems like the perfect project for one of the low cost DIY versions, but I worry about the cost of the materials. A liter of 3-D printer stock is expensive, while a huge amount of foam core is less than $10.