teaching machines

Crate

January 26, 2017 by Chris Johnson. Filed under madeup, public.

There’s something magical about wooden crates. Here’s a little program that recreates that magic on a small scale by subtracting away some triangular prisms from each face of a cube:

  

    -- We first create an overall box structure. Later,
-- we will chisel out triangles from each face to
-- make it look like a crate.
.radius = 1
.rgb = {1, 0.6, 0.2}
moveto 0, 0, 0
box

-- Now let's extrude out a pair of triangles on the +Z
-- face. We'll store that one extrusion and eventually
-- subtract it away from all six faces.
gap = 0.2
inset = 0.1
side = 2 - 2 * gap - 0.2
hypotenuse = side / cos 45

-- Bottom left
moveto -1 + gap, -1 + gap, 1 - inset
moveto -1 + gap, -1 + gap + side, 1 - inset
moveto -1 + gap + side, -1 + gap, 1 - inset
holeA = extrude 0, 0, 1, 0.15

-- Top right
moveto 1 - gap, 1 - gap, 1 - inset
moveto 1 - gap - side, 1 - gap, 1 - inset
moveto 1 - gap, 1 - gap - side, 1 - inset
holeB = extrude 0, 0, 1, 0.15

cutout = holeA or holeB

-- We've now got our core structure and the cutout
-- geometry. Let's apply the cutout to each face.

subtract

transform cutout -- +Z
rotate 0, 1, 0, 90
transform cutout -- +X
rotate 0, 1, 0, 90
transform cutout -- -Z
rotate 0, 1, 0, 90
transform cutout -- -X
rotate 0, 0, 1, 90
transform cutout -- -Y
rotate 0, 0, 1, 180
transform cutout -- +Y

    
    
    
  
  
    

    -- We first create an overall box structure. Later,
-- we will chisel out triangles from each face to
-- make it look like a crate.
.radius = 1
.rgb = {1, 0.6, 0.2}
moveto 0, 0, 0
box

-- Now let's extrude out a pair of triangles on the +Z
-- face. We'll store that one extrusion and eventually
-- subtract it away from all six faces.
gap = 0.2
inset = 0.1
side = 2 - 2 * gap - 0.2
hypotenuse = side / cos 45

-- Bottom left
moveto -1 + gap, -1 + gap, 1 - inset
moveto -1 + gap, -1 + gap + side, 1 - inset
moveto -1 + gap + side, -1 + gap, 1 - inset
holeA = extrude 0, 0, 1, 0.15

-- Top right
moveto 1 - gap, 1 - gap, 1 - inset
moveto 1 - gap - side, 1 - gap, 1 - inset
moveto 1 - gap, 1 - gap - side, 1 - inset
holeB = extrude 0, 0, 1, 0.15

cutout = holeA or holeB

-- We've now got our core structure and the cutout
-- geometry. Let's apply the cutout to each face.

subtract

transform cutout -- +Z
rotate 0, 1, 0, 90
transform cutout -- +X
rotate 0, 1, 0, 90
transform cutout -- -Z
rotate 0, 1, 0, 90
transform cutout -- -X
rotate 0, 0, 1, 90
transform cutout -- -Y
rotate 0, 0, 1, 180
transform cutout -- +Y

  
  expand

I printed the model in wood filament, and I can almost see a miniature dock worker sitting on it and eating his lunch: