Paper Topo Models With Vector Cutter

If there’s a science fair coming up, this trumps just about any 2D poster. It’s a 3D topographical map of an inactive Slovakian volcano, Poľana. [Peter Vojtek] came up an easy way to generate SVG topo patterns using Ruby.

Topographical data is available through the MapQuest API. You should be able to model just about any part of the world, but areas with the greatest elevation difference are going to yield the most interesting results. The work starts by defining a rectangular area using map coordinates and deciding the number of steps (sheets of paper representing this rectangle). The data are then chopped up into tables for each slice, converted to SVG points, and a file is spit out for the blade cutting machine. Of course you could up the game and laser cut these from more substantial stock. If you have tips for laser-cutting paper without singing the edges let us know. We’ve mostly seen failure when trying that.

The red model explained in [Peter’s] writeup uses small cross-pieces to hold the slices. We like the look of the Blue model which incorporates those crosses in the elevation representation. He doesn’t explain that specifically but it should be easy to figure out — rotate the rectangle and perform the slicing a second time, right?

If you’re looking for more fun with topography we’ve always been fond of [Caroline’s] bathymetric book.

18 thoughts on “Paper Topo Models With Vector Cutter

  1. Is there any way to define the kerf and/or sheet thickness?

    “Why can’t you cut through multiple layers of a book with a laser cutter?” For the same reason you can’t burn through (many) multiple sheets with a torch. Paper is rather dense and has a lot of resistance to further burning when turned to carbon. You can waterjet through multiple sheets of paper but it will still get slightly wet, even using waterjet brick and no abrasives.

    1. I’d think you could cut through a book with a laser.

      First, you’d need a lot of power. The burning needs to be explosive, so that enough physical force is generated that all carbon generated is blown away from the cutting path. Pulsed operation is probably the only practical way to produce enough power. Not an option with cheap and readily available laser diodes. I’m not sure if a plain CW CO2 laser tube could be used in a pulsed mode at higher than average power, or what the effect on lifetime would be.

      Second, the laser has a short depth of focus. If you simply attempt to cut in a straight line through a deep object like a book, even if you adjust the focus along the way, it won’t work. As you go deeper, most of the laser energy will be blocked by previous layers of paper, while still wide and unfocused. And that will leave carbon behind, so then you’re screwed. But if you account for the angle of the laser beam, and cut a wide enough channel on each layer before proceeding to lower layers, then it’s possible. Maybe.

      I bet I could cut through a book with my old flashlamp-driven Nd:YAG laser rangefinder, though it would take a VERY long time!

      As for whether all this could be done without leaving a charred edge, I don’t know. Maybe use of high power pulses could manage that too. As an example, there are laser erasers using pulsed energy which supposedly remove ink/toner from paper, thinning the paper in the process, but without leaving any char:

      1. I mean, sure you could eventually cut through a book with a laser. Here is RHNB guy putting, well a RHNB on sheets of paper.

        There is a pretty fair amount of energy in that RHNB and it doesn’t really penetrate very far. It’s not the same as a laser of course but lasers do not really cut well through thicker materials unless you can change the focal point on the fly. Even then though, you are going to have to blow through the carbon layers. It’s not a great application for lasers for the most part to cut through thick stacks of paper. Use a commercial quality knife to shear through multiple sheets at once, albeit in a generally linear fashion or a waterjet if you want to get really fancy. I don’t have any better suggestions at this time.

  2. I can model our local topographic features with a single, uncut sheet of paper, laid flat.

    Actually this has some interesting ramifications for building other slightly larger structures (furniture?) out of thin, sheet material.

  3. I like the look of the red one, personally… but I dig the concept of the blue. If not for topography, then certainly for graphical visualization… if one axis was red and the other blue, for instance. It’s quite cool to see these in physical form.

  4. Cool. But I think the each sliceform box should be at the sampling frequency, ie there is no further contour detail within each section, only straight, or perhaps smoothed lines. Of course the whole thing would have to be much bigger, or the boxes much smaller, to capture the same detail.

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