Design Challenge: Chesapeake Bay Watershed

July 2, 2015

Challenge: Design and fabricate a Chesapeake Bay Watershed terrain model.

A few months ago, I was asked by a teacher to 3D print a terrain model of the Chesapeake Bay Watershed for a summer STEM camp. She wanted a 3D model to help students understand how water flows into the Chesapeake Bay from a large geographic region. Her students have difficulty making sense of a paper topographic map and she thought a 3D printed model could help. Ideally she wanted the map to be very large, up to 4′ x 4′.

Display at Maryland rest stop on 95.

Geographic region encompassed by the watershed.

I spent several months trying to find an easy way to create an STL model of the Chesapeake Bay Watershed that I could 3D print. I went through multiple dead ends and have included links and tools I tried in case they help someone else. I asked for help from the local ArcGIS expert and while he investigated he never got back to me with a solution. I finally found a brute force solution that was pretty labor intensive. On the positive side, I was able to create version of the watershed on a 3D printer, laser cutter and paper cutter. I finally settled on a 1 foot by 2 foot model laser cut out of colored mat board to create a beautiful museum quality piece. The STL can be found on Thingiverse http://www.thingiverse.com/thing:908712 and the model can be edited in Tinkercad https://www.tinkercad.com/things/aq5nCOnZCEA.

I would appreciate any assistance in creating a simplified workflow for similar projects. I’ve had several requests for a 3D printable map of the regions of Virginia. (I had a promising conversation with someone from Esri about an ArcGIS workflow at ISTE 2015.)

My Overly Complicated Multi-Step Method

-Download 4200 Arc Second terrain tiles of Chesapeake Bay Watershed area with Terrain2STL web app. (4200 Arc Seconds = 1.16666667 degrees) http://jthatch.com/terrain2stl/

-Arrange and repair terrain tiles in Netfabb Basic. Export individual tiles. (Netfabb Basic does not allow combining STLs.)

-Import and combine repaired tiles into a single STL model in Meshmixer.

-Repair single STL model using Netfabb Basic.

-Reduce model using Meshmixer to reduce file size.

-Convert STL model to SVG slices with Slic3r.

-Create individual files of major shapes contained in layers of SVG file in Illustrator. (Selected 9 equally spaced layers.)

-Clip layer files using outline of Chesapeake Bay Watershed in Illustrator. (Outline extracted from a pdf map at http://www.chesapeakebay.net/)

-Extrude and stack individual layers using Tinkercad.

-Export final STL model from Tinkercad.

-Repair and resize final STL model for print in Netfabb.

Tools & Resources Investigated (Couldn’t figure out how to make these work.)

-3DEM, Accutrans, Grass GIS, TileMill, 123D Design, 123D Make, ArcGis, MeshLab, Autodesk Fusion, DEM2TOPO