Bonsai Mountains

Inspiration

At the moment, in the never-ending, ever re-created moment of this peaceful, sunlit little valley, he was fiddling with the little mirrors and shovels and morphic resonators and even stranger devices required to make a mountain grow to no more than six inches high.

Terry Pratchett, Thief of Time

Design

I made two mountains: a small circular region (5.3 square miles), and a larger rectangular region (13.7 square miles).

I traced a topological map of the area in blender, adding each vertical stage to a different vertex group. I also stitched up the edges of the map (manually, after getting frustrated with failed scripting).

Then, I used a python script to displace each vertex group to the appropriate height.

Last, I used the "Fill" command to automatically make faces. This partially worked, but I still had to go through and clean up glitchy geometry. I also added a box around the mountain to leave room for the silicon mold walls.

Cutting

I used the Modela to cut my design out of wax. For the rough cut, I used an overlap of 0.75, full cut out (-1 for offsets) speed of 20, and pass depth of 0.5mm, which was probably too small; 1 mm would have worked just as well.

For the finish cut, I used an overlap of 0.1 and only did a single pass.

Casting

I cast a negative mold in silicon, then a positive in Drystone. Thanks to John for coming in on Saturday - this gave me time to make the second, larger chunk of the topological map.

Results

Source

Blender file (3 MB)
Includes various stages of construction on different layers.