DonutCutter.frink

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/** This renders a 3-D model to render a (center-only) doughnut/biscuit cutter
    to Wavefront .obj file format for 3-D printing.

    See: http://paulbourke.net/dataformats/obj/
*/


// These can be altered and the model will be automatically recalculated.
sides = 100
outerDiam = 1.2 cm
stopDiam = outerDiam + .4 cm
innerDiam = outerDiam - 1 mm
cylHeight = 1.75 in
cutterHeight = cylHeight + 3 mm
stopHeight = 4 mm

w = new Writer["DonutCutter" + format[outerDiam, cm, 2] + ".obj"]
w.println["# Doughnut cutter by Frink\n"]
w.println["o DoughnutCutter\n"]

cylOutBottom = new array[sides]
cylOutTop    = new array[sides]
cutterTop    = new array[sides]
cylInBottom = new array[sides]
stopBottomOut = new array[sides]
stopTopOut  = new array[sides]

z0 = 0 mm
z1 = -stopHeight

angleStep = circle/sides

// The length unit
u = mm

for i = 0 to sides-1
{
   angle = i angleStep

   xcyl = outerDiam/2 cos[angle]
   ycyl = outerDiam/2 sin[angle]
   zt = cylHeight

   xcutter = innerDiam/2 cos[angle]
   ycutter = innerDiam/2 sin[angle]

   //
   cylOutBottom.push[[xcyl, ycyl, z0, i+1]]
   cylOutTop.push[[xcyl, ycyl, cylHeight, sides+i+1]]
   cutterTop.push[[xcutter, ycutter, cutterHeight, 2 sides+i+1]]
   cylInBottom.push[[xcutter, ycutter, z1, 3 sides+i+1]]

   xstop = stopDiam/2 cos[angle]
   ystop = stopDiam/2 sin[angle]
   stopBottomOut.push[[xstop, ystop, z1, 4 sides+i+1]]
   stopTopOut.push[[xstop, ystop, z0, 5 sides+i+1]]
}

w.println["# Vertex list \n"]

w.println["\n# Cyl out bottom"]
dumpVertices[cylOutBottom, w, u]

w.println["\n# Cyl out top"]
dumpVertices[cylOutTop, w, u]

w.println["\n# Cutter top"]
dumpVertices[cutterTop, w, u]

w.println["\n# Cylinder inner"]
dumpVertices[cylInBottom, w, u]

w.println["\n# Stop top bottom"]
dumpVertices[stopBottomOut, w, u]

w.println["\n# Stop outer top"]
dumpVertices[stopTopOut, w, u]

w.println["# Face list\n"]
//w.println["usemtl Default"]

// Now output the faces.  These should be output by vertex numbers in a
// counterclockwise "out" fashion.

topFace = "f"
bottomFace = new array

for i = 0 to sides-1
{
   // Cyl sides
   w.println["\n# Cyl sides"]
   [xt0, yt0, zt0, ovt0] = cylOutTop@i
   [xb0, yb0, zb0, ovb0] = cylOutBottom@i
   [xt1, yt1, zt1, ovt1] = cylOutTop@((i+1) mod sides)
   [xb1, yb1, zb1, ovb1] = cylOutBottom@((i+1) mod sides)
   w.println["f $ovt0 $ovb0 $ovb1 $ovt1"]

   // Cutter sides
   w.println["\n# Cutter sides"]
   [cutx0, cuty0, cutz0, cutv0] = cutterTop@i
   [cutx1, cuty1, cutz1, cutv1] = cutterTop@((i+1) mod sides)
   w.println["f $cutv0 $ovt0 $ovt1 $cutv1"]

   // Inner surface of cylinder
   w.println["\n# inner sides"]
   [xb0, yb0, zb0, ivb0] = cylInBottom@i
   [xb1, yb1, zb1, ivb1] = cylInBottom@((i+1) mod sides)
   w.println["f $cutv0 $cutv1 $ivb1 $ivb0"]

   // Bottom sides of stop.
   w.println["\n# Bottom sides of stop"]
   [xb0, yb0, zb0, sbo0] = stopBottomOut@i
   [xb1, yb1, zb1, sbo1] = stopBottomOut@((i+1) mod sides)
   w.println["f $ivb0 $ivb1 $sbo1 $sbo0"]

   // Sides of stop.
   w.println["\n# Sides of stop"]
   [xt0, yt0, zt0, sto0] = stopTopOut@i
   [xt1, yt1, zt1, sto1] = stopTopOut@((i+1) mod sides)
   w.println["f $sto0 $sbo0 $sbo1 $sto1"]
   
   // Upper surface of stop.
   w.println["\n# Upper Surface of stop"]
   w.println["f $sto0 $sto1 $ovb1 $ovb0"]
}

w.close[]


/** Dump an array of vertices */
dumpVertices[array, writer, u] :=
{
   for [x,y,z] = array
      writer.println["v " + formatFix[x, u, 5] + " " + formatFix[y, u, 5] + " " + formatFix[z, u, 5]]
}


View or download DonutCutter.frink in plain text format


This is a program written in the programming language Frink.
For more information, view the Frink Documentation or see More Sample Frink Programs.

Alan Eliasen was born 19093 days, 17 hours, 33 minutes ago.