Considerations for this method
Limitations for milling context buildings
In foam, buildings can be about 2" tall. Tall buildings must be at least 1/4" apart. Shorter buildings (<1") can be 1/8" apart.
In wood, buildings can be about 1" tall.
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Material choices
| METHOD | MATERIAL | COST ($/sf) | TIME: file prep | TIME: fab | TIME: assembly | TIME: total | MATERIAL RECYCLABILITY | |
|---|---|---|---|---|---|---|---|---|
 | CNC milling - smooth terrain | white foam | $8 | 7 | 2 | 0.25 | 9.25 | no |
 | CNC milling - smooth terrain | plywood | $40 | 9.5 | 1 | 17.25 | yes | |
 | CNC milling - smooth terrain | hardwood (poplar) | $34 | 9.5 | 1 | 17.25 | yes | |
| CNC milling - smooth terrain | high density foam | $83 | 7 | 2 | 0.25 | 9.25 | no | |
 | CNC milling - stepped terrain (fine) | white foam | $8 | 14 | 3.6 | 0.25 | 17.85 | no |
| CNC milling - stepped terrain (1/16" contours) | white foam | $8 | 7 | 2 | 0.25 | 9.25 | no |
File preparation: Rhino
- Generally, the rhino file prepared for milling must contain the following layers:
- Stock: a box, at the world origin, representing the size of the block of your milling material.
- Topography: a single NURBS surface for smooth terrain, or a series of flat surfaces for stepped terrain.
- Features: layer(s) with NURBS surfaces for roads, water, etc.
- For each features layer, there should be another layer with boundary curves for each feature surface.
- Buildings: If buildings are to be milled with the base, include a layer with NURBS surfaces at the tops of buildings.
- A layer with boundary curves for each building top surface.
- Buildings too large or too small to be milled with the topography need pockets. Include a layer with curves outlining the bases of these buildings (at the z depth you want the bottom of the pocket cut).
- Final contour: a layer with a curve tracing the four outside edges of the topography layer, and the same curve projected to z=0.
- This file can be imported directly into Mastercam.
File preparation: Mastercam
- See the CNC tutorial for more detail. In general, you will need to use a template MasterCAM file, import your geometry, assign it to pre-defined toolpaths and adjust the toolpath parameters for your material.
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