Bash and GCMC source code: Laser cutter marquetry / coaster test piece generator

marq.sh

#!/bin/bash
# Marquetry test piece
# Ed Nisley KE4ZNU - 2022-07-01

Flags='-P 4 --pedantic'       # quote to avoid leading hyphen gotcha

SVGFlags='-P 4 --pedantic --svg --svg-no-movelayer --svg-opacity=1.0 --svg-toolwidth=0.2'

# Set these to match your file layout

ProjPath='/mnt/bulkdata/Project Files/Laser Cutter/Marquetry/Source Code'

LibPath='/opt/gcmc/library'

ScriptPath=$ProjPath
Script='Marquetry Test Piece.gcmc'

leaves="NumLeaves=$1"
aspect="LeafAspect=$2"

fn=Marq-$1-$2.svg
echo Output: $fn

gcmc $SVGFlags -D "$leaves" -D "$aspect" \
 --include "$LibPath" \
 "$ScriptPath"/"$Script" > "$fn"

Marquetry Test Piece.gcmc

// Marquetry Laser Cuttery Test Piece
// Ed Nisley KE4ZNU
// 2022-07-01 Simplest possible mandala

layerstack("Frame","Leaves","Rim","Base","Center","Tool1");  // SVG layers map to LightBurn colors

//-----
// Library routines

include("tracepath.inc.gcmc");
include("tracepath_comp.inc.gcmc");
include("varcs.inc.gcmc");
include("engrave.inc.gcmc");

FALSE = 0;
TRUE = !FALSE;

//-----
// Command line parameters

// -D various useful tidbits
// add unit to speeds and depths: 2000mm / -3.00mm / etc

if (!isdefined("OuterDia")) {
  OuterDia = 120.0mm;
}

if (!isdefined("CenterDia")) {
  CenterDia = 20.0mm;
}

if (!isdefined("NumLeaves")) {
  NumLeaves = 5;
}

if (!isdefined("Sash")) {
  Sash = 4.0mm;
}

if (!isdefined("LeafAspect")) {
  LeafAspect = 0.40;
}

// Leaf values

LeafStemAngle = 360.0deg/NumLeaves;                     // subtended by inner sides
LeafStemHA = LeafStemAngle/2;

LeafLength = OuterDia/2 - Sash - (Sash/2)/sin(LeafStemHA);

LeafWidth = LeafAspect*LeafLength;
L1 = (LeafWidth/2)/tan(LeafStemHA);
L2 = LeafLength - L1;
// message("Len: ",LeafLength," L1: ",L1," L2: ",L2);

LeafTipHA = to_deg(atan(LeafWidth/2,L2));      // subtended by outer sides
LeafTipAngle = 2*LeafTipHA;

// message("Width: ",LeafWidth);
// message("Tip HA: ",LeafTipHA);

LeafID = CenterDia + 2*Sash;
LeafOD = LeafID + LeafLength;

// message("ID: ",LeafID," OD: ",LeafOD);

// Find leaf and rim vertices

P0 = [(Sash/2) / sin(LeafStemHA),0.0mm];

if (P0.x < LeafID/2) {
  a = 1 + pow(tan(LeafStemHA),2);
  b = -2 * tan(LeafStemHA) * (Sash/2) / cos(LeafStemHA);
  c = pow((Sash/2) / cos(LeafStemHA),2) - pow(LeafID/2,2);
  // message("a: ",a);
  // message("b: ",b);
  // message("c: ",c);
  xp = (-b + sqrt(pow(b,2) - 4*a*c))/(2*a);
  xn = (-b - sqrt(pow(b,2) - 4*a*c))/(2*a);
  y = xp*tan(LeafStemHA) - (Sash/2) / cos(LeafStemHA);
  // message("p: ",xp," n: ",xn," y: ",y);
  P1 = [xp,y];
}
else {
  P1 = P0;
}

P2 = P0 + [L1,LeafWidth/2];
P3 = P0 + [LeafLength,0mm];

P4 = P3 + [Sash/sin(LeafTipHA),0.0mm];
P5r = P4.x * sin(LeafTipHA) / sin(180deg - LeafStemHA - LeafTipHA);
P5 = rotate_xy([P5r,0.0mm],LeafStemHA);
P6 = rotate_xy(P4,LeafStemAngle);

t2 = pow(tan(-LeafTipHA),2);
a = 1 + t2;
b = -2 * t2 * P4.x;
c = t2 * pow(P4.x,2) - pow(P3.x,2);

xp = (-b + sqrt(pow(b,2) - 4*a*c))/(2*a);
xn = (-b - sqrt(pow(b,2) - 4*a*c))/(2*a);
y = (xp - P4.x)*tan(-LeafTipHA);
// message("p: ",xp," n: ",xn," y: ",y);

P4a = [xp,y];
P6a = rotate_xy(P4a,LeafStemAngle - 2*atan(P4a.y,P4a.x));
// message("P4a: ",P4a);
// message("P6a: ",P6a);

// message("P0: ",P0);
// message("P1: ",P1);
// message("P2: ",P2);
// message("P3: ",P3);
// message("P4: ",P4);
// message("P5: ",P5);
// message("P6: ",P6);

// Construct paths

LeafPoints = {P1,P2,P3,[P2.x,-P2.y],[P1.x,-P1.y]};

if (P0 != P1) {
  StemArc = varc_ccw(P1 - [P1.x,-P1.y],LeafID/2);
  StemArc += [P1.x,-P1.y];
  LeafPoints += StemArc;
}

RimChord = length(P4a - P6a);
RimThick = OuterDia/2 - Sash - length(P5);

RimPoints = {P4a,P5,P6a};
RimArc = varc_cw(P4a - P6a,P4a.x);
RimArc += P6a;
RimPoints += RimArc;

//--- Lay out the frame

linecolor(0xff0000);

layer("Frame");

goto([CenterDia/2,0mm]);
circle_cw([0mm,0mm]);

repeat(NumLeaves;i) {
  a = (i-1)*LeafStemAngle;
  tracepath(rotate_xy(LeafPoints,a));
}

repeat(NumLeaves;i) {
  a = (i-1)*LeafStemAngle;
  tracepath(rotate_xy(RimPoints,a));
}

linecolor(0xff0000);

goto([OuterDia/2,0]);
circle_cw([0mm,0mm]);

//--- Lay out internal pieces for oriented cutting

// baseplate

layer("Base");

relocate([OuterDia + 2*Sash,0]);
goto([OuterDia/2,0]);
circle_cw([0mm,0mm]);

// central circle

layer("Center");

relocate([OuterDia/2 + Sash,-(OuterDia - CenterDia)/2]);
goto([CenterDia/2,0mm]);
circle_cw([0mm,0mm]);

// leaves

layer("Leaves");

repeat(NumLeaves;i) {
  org = [LeafWidth/2 - OuterDia/2,-(OuterDia + Sash)];
  relocate([(i-1)*(LeafWidth + Sash) + org.x,org.y]);
  tracepath(rotate_xy(LeafPoints,90deg));
}

// rim

layer("Rim");

repeat(NumLeaves;i) {
  org = [-Sash,-(OuterDia + 2*Sash + RimChord/2)];
  relocate([(i-1)*(RimThick + Sash) + org.x,org.y]);
  tracepath(rotate_xy(RimPoints,180 - LeafStemHA));
}


// Debugging by printf()

if (FALSE) {
  layer("Tool1");
  linecolor(0xff1f00);

  goto([Sash/2,0mm]);
  circle_cw([0mm,0mm]);

  goto(P0);
  circle_cw([0mm,0mm]);

  goto([0,0]);
  move([OuterDia/2,0]);

  goto([0,0]);
  move(OuterDia/2 * [cos(LeafStemHA),sin(LeafStemHA)]);

  goto(P2);
  move_r([0,-LeafWidth/2]);

}