3D Contour Map

Some years ago I wrote an instructable describing how to easily make a 3D topographical map using 3 tools - a web utility called Terrain2STL, a piece of software called Slicer for Fusion360, and a laser cutter. Unfortunately, Slicer became defunct and that instructable is no longer useful. Happily, new tools have sprung up that do what Slicer did (and more), and this instructable will show you how to quickly make your own 3D topographical map using the web tool kiri:moto. Shout out to the author, who responded amazingly to a feature request from me to make the tool more powerful in this particular context (adding outlines of the next layer to each slice to aid alignment). Both Terrain2STL and kiri:moto are super easy and free to use as web tools. You could be laser cutting your map minutes after reading this tutorial!

You'll need a sheet of plywood or MDF or cardboard, whatever you want your map made out of. You'll need access to a laser cutter. And some wood glue and a little patience. This map used one 500 × 800 mm (20 × 32") sheet of 3 mm (1/8") plywood (and a small offcut of blue acrylic, also 3 mm).

Go to the wonderful Terrain2STL utility. You will be greeted by an interactive Google map. Navigate to the geographical area of interest by zooming and dragging, and click "Center To View". Go next to Model Details, and use the Box Size slider to make the red box large enough to incorporate the feature you want. Be aware however that the larger the feature you select, the bigger the STL file you will end up downloading. You're ready to make your STL file! Click Create and Download. Save the STL. I attach the one I used, just in case someone else wants a 3D map of the same area...

Go to Kiri:Moto and go to the LASER workspace (button, top left). Go to Files > Import and select your STL. It will appear on the workspace. On the right, click on Output, and select Layer Stacking (if this doesn't appear, go to Settings, top right, and make sure your version is at least 3.1). Click on Slice, and the STL will appear as a contour map. Tweak the appearance of the map using the Offset (affects where the slices start) and Height (affects number of layers) settings. You're looking for a map that contains the right number of layers (how tall do you want your map to be?) and you can sometimes use the offset to minimize the number of tiny circles that appear on your map. Click on Slice > Preview, and you will get the layers laid out for laser cutting, with black marking the cut lines and red the layout lines. Click Export, and download as svg.

Pick a location that means something to you (or if it is a gift, to that person). I chose the Saanich Inlet on Vancouver Island (BC, Canada), a local fjord with great hikes lining the sides. The corkscrew lookout is the Malahat Skywalk, recently built to highlight the views.

Import the svg file into the program you use for laser cutting. Rearrange and resize the layers to best fit on your laser bed. Consider deleting the smallest pieces (and their corresponding layout lines) because they're a pain to keep track of, are fragile, and are easily lost or broken.

Send to the laser cutter. I used 3 mm (1/8" plywood), and on the Speedy360 I have access to this meant 100% laser power at 0.5% speed for the cut lines, and 20% laser power at 10% speed for the layout lines (if that sounds slow, it's not really, because 100% is REALLY fast).

Assembling these maps is fun, in the same way jigsaw puzzles are. Just line each piece up with the layout line of the right size, and fix together with a thin layer of wood glue. Press down firmly and make sure the pieces are aligned exactly. I don't use clamps or weights. The animation above shows me assembling a cardboard model of Mt Taranaki using a glue stick. The simpler the terrain, the easier the puzzle! Sometimes there can be a little ambiguity, especially with the smaller pieces, but usually inspection of the grain direction can fix that. If two pieces are genuinely indistinguishable, it of course doesn't matter which one you put where.

If you have water in your map, you might like to represent it with a piece of blue acrylic. Just edit the bottom layer and cut out the appropriate piece. It doesn't need gluing in place provided you ensure it's a tight fit when you're gluing it up. Great way to use up an offcut.

Note: Lakes sometimes look wrong because the contour is at the wrong height (above/below water level). Play around with the layer height and offset in kiri:moto to get this right.