My girlfriend belongs to a group of volunteers that remove non-native plant species from Edgewood park. Over the last 30 years they have made the place once again hospitable for the endemic endangered plants and insects. Friends of Edgewood Park does a lot of good in the park.
At gatherings the group is always saying "we worked at spot XYZ last week." I hike in the park all the time, but I don't know the location of these place names. I thought it would be cool to use the laser cutter to make an accurate relief model of the park. I wanted it to be small enough to carry around to the meetings.
Now when someone mentions a certain location I can pull out the model and ask, "where exactly is that?" They are amazed that I have the model, then more amazed that I made it myself at TechShop. Once they point out the location, then at least I know where they're talking about.
- Epilog Helix Laser Engraver / Cutter (TechShop)
- Several big sheets of one-eighth inch mat board (art supply or frame shop)
- Topographic map of the area you want to model
- Two feet of 14 AWG copper wire
How I did it
1. Get the Map: Obtain a topographic map of the area. The USGS web site has links to some great maps. You can either take a photo of one, get a PDF of one, or do a screen capture.
2. Clean the Map: Using a bit map editor (I used CorelDraw) you need to remove all the dark lines except the contour lines. See the two detail photos, one before I removed the extraneous stuff, the other after. Note that I removed the elevation numbers as well. The next photo shows the entire topographic map with extraneous stuff removed. Note that I wasn't super careful in cleaning up the image. How much is enough? The next step will tell you that.
3. Convert to Lines: In CorelDraw select the bit map and bring up the Trace Lines tool. I used the settings Technical Drawing, moderate Smoothing, and high Corner Smoothing. Adjust the Detail Amount until the preview shows most of your contour lines. If you specify too much detail then you'll see artifacts crossing your contour lines. If you can't get the preview to look the way you want, then go back to the previous step and clean up your bit map a little more. I went back and forth several times until I got a fairly clean set of contour lines. The messier the contour lines are, the more work you have to do in the next step. When you are done, hide the bit map. Aha! just the contour lines are shown!
4. Clean up the Lines: Now select the point editing tool and zoom in on your contour lines. Look for little bits sticking out and delete those points. If you find this too tedious, then go back to Clean the Map or Convert to Lines. Working more there may leave you with less to do in this step.
5. Add Registration Holes: Create a circle 0.125 inches in diameter. Locate each high point in your terrain. Put a circle on top of each high point. You'll use these holes to align the different layers when you assemble the model. You can see the holes in each of photos of my parts.
6. Add Outline: Create a square around the entire project.
7. Hairlines? The Epilog will only cut lines in your project that are "hairline" width. Use control-a to select all lines and then right-click, select Object Properties, Line Width. Set it to Hairline.
8. Cut It Out: Put a piece of one-eighth inch thick mat board in the Epilog. Select the inner most contour lines and all the registration holes that fall within that contour. Print to the Epilog. On the back of this piece write "1".
9. Repeat Until Done: Put in another piece of mat board. Working out from the previous contour lines, select the next set of lines. If the lines cross your Outline box, then select that too. Always be sure to select ALL the registration holes that lie within the contour you are cutting. On the back of each piece write the next higher number; if you don't it is easy to get confused later and have your contour model turn into a 3d jigsaw puzzle!
10. Assembly: Now strip the insulation off of some 14 AWG wire. Insert the wire into the registration holes and slide each layer onto the wires in order.
11. Glue: If you want, coat the layers with a small amount of white glue and press tightly together until the glue sets.
Enjoy your new relief model!
Jim (my web site)