This is a follow up to our discussion on my example topological carving during the CNC SIG meeting. Was great meeting everyone there. I enjoyed it and was impressed by all the different projects and discussion. There were some questions about my process for the Terrain carve I did with trails and streets. This is still work in progress, but here is where I am. Happy to answer any questions.
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I used this good YouTube video for initial guidance and used many of the suggestions there.
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Use TouchTerrain to download a STL file of area to be milled
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I brought the STL file into Blender to do some minor modifications. For example I leveled the terrain in a corner of the area as it had a lot of elevation change and was distracting to the area of interest. I also used the extrude tool to create a flat raised area to engrave the name of the region. I then saved that back into a STL file.
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Next was getting the trail and street info. I am currently using a windows tool called maperitive to make a custom map that only has the streets and trails of interest on it, and exported that as a SVG file. For the trails, I also tried using the gpx files from a hike I did and converting that to SVG via the https://mygeodata.cloud/ website. That gave good results, but I preferred having the streets and trails together so I only had to scale and position one set of data. If I were not including streets then I would probably go with converting the GPX to SVG.
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In VCarve Pro I create a new project and import the STL file via the 3D model importer. I scaled it at that point to match my intended stock. I then imported the streets and trails SVG file. This is where it currently gets ugly. I manually scaled and positioned the streets and trails vectors over the 3d terrain layer as accurately as possible using visual clues.
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Finally created the toolpaths and carved the piece. Rough machining was done with a 1/4" downcut end mill, 3D finish was done with a 1/16" tapered ball nose, Text was done with a 60 degree V-Bit. The trail is a profile toolpath with a 30 degree v-bit and finally streets are a profile toolpath with a 90 degree v-bit.
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I tried different techniques to try and color/highlight the trails after carving and am finding the best so far is just a mechanical pencil with thin lead that easily rides inside the v groove. I would have preferred to laser engrave the streets and trails, but I could not find a way to do that with the lasers we have in the shop.
Another resource for creating the topographical information that looked interesting was Blender GIS. I did not use this but may investigate.
The search for terrain information also uncovered this very interesting plugin to do 3D printing of topography with your hike included called TrailPrint3D. This is a plugin for Blender. I will be planning on taking the 3D printing class so I can give it a try. I like the idea of creating a wall display with a grid of hikes from different regions. The source code is available, so I may look into modifying it to create a STL file that would make the trail more appropriate for CNC or maybe export the trail separate from the terrain.
