Laser-Cut Topography: Offset Method

Owned by Former user (Deleted)
Last updated: Aug 28, 2015
3 min read

Considerations for this method

Pros:
  • Much less material used than other topography methods
  • Quick to laser cut
  • Easy to set up laser files
  • If model scale, given topographic contour interval, and material thickness correspond, model can be prepared entirely in 2D
Cons:
  • Any vertical surface more than a couple layers thick will be empty in the model
    • So vertical surfaces (including buildings) must be modeled separately from topography
On this page

 

 

Material options

(image)METHODMATERIALCOST ($/sf)

TIME:

file prep

TIME:

fab

TIME:

assembly

TIME:

total

MATERIAL RECYCLABILITY
 Horizontal laser-cut topo (offset method)4ply museum board$10
 6
2 h for base,
4 h for buildings 
 2.5
2 h for base,
0.5 h for buildings 
 10
4 h for base,
6 h for buildings 
18.5yes
 Horizontal laser-cut topo (offset method)2ply museum board$5
 9
3 h for base,
6 h for buildings 
 4
3 h for base,
1 h for buildings 
 15
6 h for base,
9 h for buildings 
28yes
Horizontal laser-cut topo (offset method)crescent board$10
 6
2 h for base,
4 h for buildings 
 2.5
2 h for base,
0.5 h for buildings 
 10
4 h for base,
6 h for buildings 

18.5

yes

File preparation

  1. Generate topography lines at a vertical distance that matches the thickness of your modeling material.
    1. If your base file contains contours at a different resolution, use the RhinoTerrain plugin (available in the Software folder on Goliath) to make a 3D mesh from the given contours.



    2. Use the Contour command to create appropriately spaced contour lines from the new 3D mesh.

  2. Draw pieces for the sides of the model.



  3. Split the contours into two rhino layers, A and B (alternating every other level—red and black in the image below).


     
  4. Turn on a layer with building footprints. Flatten everything to the z-plane.
  5. Distribute the building footprints to the appropriate layer(s). Click on the gif below to enlarge.
    1. First, use the building footprints to trim out any contour lines inside them.
    2. The part of the building footprint at the lowest part of the terrain goes on the same layer as the next lowest topography line.
    3. The rest of the building footprint goes on both layers. (The green lines in the image below should be moved to layer A AND copied to layer B.)
    4. If the building doesn't cross topography lines, put the whole footprint on the layer of the next lowest topography line.



  6. Make a copy of all the contours next to the originals.
    1. In the first group, move layer A into your CUT layer and B into your ETCH layer. 
    2. In the second group, move layer A into your ETCH layer and B into your CUT layer.



  7. Add any etching/hatching for roads, etc. to both groups.

Making the model

  1. Laser cut the two sets of contours and side pieces.
  2. To assemble the model, you'll glue up the pieces alternating between one set and the other.

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