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#!/usr/bin/env python3
Generates Inkscape SVG file containing box components needed to
laser cut a tabbed construction box taking kerf and clearance into account
Original Author -- 2011 elliot white
Forked -- 2013 Reid Borsuk
Updated for 0.91 2016 Maren Hachmann
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <>.
__version__ = "0.8rb"
import inkex
import math
from lxml import etree
import math
def drawS(XYstring): # Draw lines from a list
style = { 'stroke': '#000000', 'fill': 'none' }
drw = {'style': str(inkex.Style(style)),inkex.addNS('label','inkscape'):name,'d':XYstring}
etree.SubElement(parent, inkex.addNS('path','svg'), drw )
def draw_SVG_ellipse(centerx, centery, radiusx, radiusy, start_end):
style = { 'stroke' : '#000000',
'fill' : 'none' }
ell_attribs = {'style': str(inkex.Style(style)),
inkex.addNS('cx','sodipodi') :str(centerx),
inkex.addNS('cy','sodipodi') :str(centery),
inkex.addNS('rx','sodipodi') :str(radiusx),
inkex.addNS('ry','sodipodi') :str(radiusy),
inkex.addNS('start','sodipodi') :str(start_end[0]),
inkex.addNS('end','sodipodi') :str(start_end[1]),
inkex.addNS('open','sodipodi') :'true', #all ellipse sectors we will draw are open
inkex.addNS('type','sodipodi') :'arc',
'transform' :''
ell = etree.SubElement(parent, inkex.addNS('path','svg'), ell_attribs )
#draw an SVG line segment between the given (raw) points
def draw_SVG_line( x1, y1, x2, y2, parent):
style = { 'stroke': '#000000', 'fill': 'none' }
line_attribs = {'style' : str(inkex.Style(style)),
'd' : 'M '+str(x1)+','+str(y1)+' L '+str(x2)+','+str(y2)}
line = etree.SubElement(parent, inkex.addNS('path','svg'), line_attribs )
def EllipseCircumference(a, b):
Compute the circumference of an ellipse with semi-axes a and b.
Require a >= 0 and b >= 0. Relative accuracy is about 0.5^53.
import math
x, y = max(a, b), min(a, b)
digits = 53; tol = math.sqrt(math.pow(0.5, digits))
if digits * y < tol * x: return 4 * x
s = 0; m = 1
while x - y > tol * y:
x, y = 0.5 * (x + y), math.sqrt(x * y)
m *= 2; s += m * math.pow(x - y, 2)
return math.pi * (math.pow(a + b, 2) - s) / (x + y)
Gives you a list of points that make up a box.
Returns string suitable for input to drawS
def box(sx, sy,ex, ey, leaveLeftSideOpen = False):
s='M '+str(sx)+','+str(sy)+' '
s+='L '+str(ex)+','+str(sy)+' '
s+='L '+str(ex)+','+str(ey)+' '
s+='L '+str(sx)+','+str(ey)+' '
if not leaveLeftSideOpen:
s+='L '+str(sx)+','+str(sy)+' '
return s
Side function is used to render any of the sides so needs all this functionality:
isLongSide -- long sides without tabs (for cover),
truncate -- partial sides for the elipse
gap -- extend the tabs on the curved side for ease of movement
thumbTab -- Render individual boxes for slots instead of one continuous line
isTab is used to specify the male/female designation for a side so they mesh properly. Otherwise the tabs
would be in the same spot for opposing sides, instead of interleaved.
Returns a list of lines to draw.
def side(rx,ry,sox,soy,eox,eoy,tabVec,length, dirx, diry, isTab, isLongSide, truncate = False, gap = False, thumbTab = False):
# root startOffset endOffset tabVec length direction isTab
#Long side length= length+((math.pi*(length/2))/4
tmpLength = 0
correctionLocal = correction
if gap:
correctionLocal = (correction)
if isLongSide > 0:
tmpLength = length
length = isLongSide
divs=int(length/nomTab) # divisions
if not divs%2: divs-=1 # make divs odd
if isLongSide < 0:
divs = 1
tabs=(divs-1)/2 # tabs for side
if isLongSide < 0:
divs = 1
tabWidth = length
gapWidth = 0
elif equalTabs:
if isTab: # kerf correction
firstVec=0; secondVec=tabVec
if gap:
secondVec *= 2
dirxN=0 if dirx else 1 # used to select operation on x or y
diryN=0 if diry else 1
s='M '+str(Vx)+','+str(Vy)+' '
if dirxN: Vy=ry # set correct line start
if diryN: Vx=rx
if isLongSide > 0: #LongSide is a side without tabs for a portion.
length = tmpLength
if not divs%2: divs-=1
divs = float(divs)
# generate line as tab or hole using:
# last co-ord:Vx,Vy ; tab dir:tabVec ; direction:dirx,diry ; thickness:thickness
# divisions:divs ; gap width:gapWidth ; tab width:tabWidth
for n in range(1,int(divs)):
if n%2:
s+='L '+str(Vx)+','+str(Vy)+' '
s+='L '+str(Vx)+','+str(Vy)+' '
Vxs = Vx
Vys = Vy
s+='L '+str(Vx)+','+str(Vy)+' '
s+='L '+str(Vx)+','+str(Vy)+' '
if thumbTab:
(secondVec,firstVec)=(-secondVec,-firstVec) # swap tab direction
if not truncate:
s+='L '+str(rx+eox*thickness+dirx*length)+','+str(ry+eoy*thickness+diry*length)+' '
else: #Truncate specifies that a side is incomplete in preperation for a curve
s+='L '+str(rx+eox*thickness+dirx*(length/2))+','+str(ry+eoy*thickness+diry*(length/2))+' '
return s
#God class. Makes poor design, but not much object oriented in this guy...
class BoxMakerLivingHinge(inkex.EffectExtension):
def add_arguments(self, pars):
pars.add_argument('--unit',default='mm',help='Measure Units')
pars.add_argument('--inside',type=int,default=0,help='Int/Ext Dimension')
pars.add_argument('--length',type=float,default=100,help='Length of Box')
pars.add_argument('--width',type=float,default=100,help='Width of Box')
pars.add_argument('--height',type=float,default=100,help='Height of Box')
pars.add_argument('--tab',type=float,default=25,help='Nominal Tab Width')
pars.add_argument('--equal',type=int,default=0,help='Equal/Prop Tabs')
pars.add_argument('--thickness',type=float,default=10,help='Thickness of Material')
pars.add_argument('--kerf',type=float,default=0.5,help='Kerf (width) of cut')
pars.add_argument('--clearance',type=float,default=0.01,help='Clearance of joints')
pars.add_argument('--spacing',type=float,default=25,help='Part Spacing')
pars.add_argument('--hingeOpt',type=int,default=0,help='Hinge type')
pars.add_argument('--hingeThick',type=float,default=0,help='Hinge thickness')
pars.add_argument('--thumbTab',default=0,help='Add a thumb tab')
Traditional multi-slit design.
Sx, Sy : Start X, Y (pixels, not user units)
Ex, Ey : End X, Y (pixels, not user units)
space : gap between slots in the X direction, in user specified units (IE: wood between two rows of slots)
solidGap : gap between slots in the Y direction, in user specified units (IE: how much wood is left between 2 or 3 cuts)
def livingHinge2(self, Sx, Sy, Ex, Ey, space = 2, solidGap = 4):
space = self.svg.unittouu( str(space) + unit )
solidGap = self.svg.unittouu( str(solidGap) + unit )
Sy += thickness
Ey -= thickness
height = Ey - Sy
width = Ex - Sx
# inkex.utils.debug(width)
horizontalSlots = int(round(width / space))
# inkex.utils.debug(horizontalSlots)
if horizontalSlots % 2 and horizontalSlots != 1:
horizontalSlots-=1 # make it even so you end with an interior slot
# inkex.utils.debug(horizontalSlots)
space = width / horizontalSlots
grp_name = 'Living Hinge'
grp_attribs = {inkex.addNS('label','inkscape'):grp_name }
grp = etree.SubElement(parent, 'g', grp_attribs)#the group to put everything in
for n in range(0,horizontalSlots+1):
if n%2: #odd, exterior slot (slot should go all the way to the part edge)
draw_SVG_line(Sx + (space * n), Sy, Sx + (space * n), Sy+(height/4)-(solidGap/2), grp)
draw_SVG_line(Sx + (space * n), Sy+(height/4)+(solidGap/2), Sx + (space * n), Ey-(height/4)-(solidGap/2), grp)
draw_SVG_line(Sx + (space * n), Ey-(height/4)+(solidGap/2), Sx + (space * n), Ey, grp)
#even, interior slot (slot shoud not touch edge of part)
draw_SVG_line(Sx + (space * n), Sy+solidGap, Sx + (space * n), Sy+(height/2)-(solidGap/2), grp)
draw_SVG_line(Sx + (space * n), Ey-(height/2)+(solidGap/2), Sx + (space * n), Ey-solidGap, grp)
The sprial based designs are built from multiple calls of this function.
Sx, Sy : Start X, Y (pixels, not user units)
Ex, Ey : End X, Y (pixels, not user units)
reverse : specifies the spin of the spiral (1 = outer spiral is counterclockwise, -1 otherwise)
space : gap between slots, in user specified units (IE: how thick the wood remainder is)
def livingHinge3(self, Sx, Sy, Ex, Ey, reverse = 1, space = 2):
space = self.svg.unittouu( str(space) + unit )
height = (Ey - Sy)
width = (Ex - Sx)
horizontalSlots = int(math.floor(height / (space)))
if not horizontalSlots%2: horizontalSlots-=1 # make it odd otherwise the below division will result in an outer cut too thin
space = (height / horizontalSlots)
horizontalSlots = int(round(horizontalSlots * 1/2)) #We do 2 passes per render, so divide slots requirement in half
grp_name = 'Living Hinge'
grp_attribs = {inkex.addNS('label','inkscape'):grp_name }
grp = etree.SubElement(parent, 'g', grp_attribs)#the group to put everything in
centerX = Sx + (width/2)
centerY = Sy + (height/2)
for n in range(0,horizontalSlots):
newX = (((space/2) + (space*n)) * reverse)
draw_SVG_line((centerX - newX), centerY + (space/2) + (space * n), (centerX - newX ), centerY - (space * 1.5) - (space * n), grp)
if horizontalSlots - 1 != n: #Last line in center should be omited
draw_SVG_line((centerX - (space + (space/2 * -reverse)) - (space*n) ), centerY - (space * 1.5) - (space * n), (centerX + (space + (space/2 * reverse)) + (space*n) ), centerY - (space * 1.5) - (space * n), grp)
draw_SVG_line((centerX + newX ), centerY - (space/2) - (space * n), (centerX + newX ), centerY + (space * 1.5) + (space * n), grp)
if horizontalSlots - 1 != n: #Last line in center should be omited
draw_SVG_line((centerX + (space + (space/2 * -reverse)) + (space*n) ), centerY + (space * 1.5) + (space * n), (centerX - (space + (space/2 * reverse)) - (space*n) ), centerY + (space * 1.5) + (space * n), grp)
The snake based designs are built from multiple calls of this function.
Sx, Sy : Start X, Y (pixels, not user units)
Ex, Ey : End X, Y (pixels, not user units)
rotate : False means the traditional flexable design (cuts are prependuclar to long sides). True rotates 90 degrees.
mirror : mirror inverts the left and right slots, used for inverting during double design
space : gap between adjecent slots, in user specified units (IE: wood between two rows of slots, X if rotate is false, Y if true)
solidGap : gap between slot and edge, in user specified units (IE: how much wood is left between cut and edge, Y if rotate is false, X if true)
def livingHinge4(self, Sx, Sy, Ex, Ey, rotate = False, mirror = 0, space = 2, solidGap = 5):
space = self.svg.unittouu( str(space) + unit )
solidGap = self.svg.unittouu( str(solidGap) + unit )
Sy += thickness
Ey -= thickness
height = Ey - Sy
width = Ex - Sx
if not rotate:
horizontalSlots = int(round(width / space))
space = width / horizontalSlots
skew = 1 #Paint extra lines at the start and end because in this direction there are no existing lines already
horizontalSlots = int(round(height / space))
if not horizontalSlots%2: horizontalSlots-=1 #make sure we always end on the same side, otherwise we'll cut off the last tooh
space = height / horizontalSlots
skew = 0 #Don't paint the first and last lines, as they're on the cut already, and double cuts on a laser are messy
grp_name = 'Living Hinge'
grp_attribs = {inkex.addNS('label','inkscape'):grp_name }
grp = etree.SubElement(parent, 'g', grp_attribs)#the group to put everything in
for n in range(1 - skew,horizontalSlots + skew):
if not rotate:
if (n+mirror)%2:
draw_SVG_line(Sx + (space * n), Sy + solidGap, Sx + (space * n), Ey, grp)
draw_SVG_line(Sx + (space * n), Sy, Sx + (space * n), Ey - solidGap, grp)
if (n+mirror)%2:
draw_SVG_line(Sx + solidGap, Sy + (space * n), Ex, Sy + (space * n), grp)
draw_SVG_line(Sx, Sy + (space * n), Ex - solidGap, Sy + (space * n), grp)
if rotate and not mirror:
draw_SVG_line(Sx, Sy, Sx, Ey - space, grp)
draw_SVG_line(Ex, Sy + space, Ex, Ey, grp)
elif mirror:
draw_SVG_line(Sx, Sy + space, Sx, Ey, grp)
draw_SVG_line(Ex, Sy, Ex, Ey - space, grp)
def effect(self):
global parent,nomTab,equalTabs,thickness,correction, Z, unit
# Get access to main SVG document element and get its dimensions.
svg = self.document.getroot()
# Get the attibutes:
widthDoc = self.svg.unittouu(svg.get('width'))
heightDoc = self.svg.unittouu(svg.get('height'))
# Create a new layer.
layer = etree.SubElement(svg, 'g')
layer.set(inkex.addNS('label', 'inkscape'), 'newlayer')
layer.set(inkex.addNS('groupmode', 'inkscape'), 'layer')
# Get script's option values.
X = self.svg.unittouu( str(self.options.length) + unit )
Y = self.svg.unittouu( str(self.options.width) + unit )
Z = self.svg.unittouu( str(self.options.height) + unit )
thickness = self.svg.unittouu( str(self.options.thickness) + unit )
nomTab = self.svg.unittouu( str( + unit )
kerf = self.svg.unittouu( str(self.options.kerf) + unit )
clearance = self.svg.unittouu( str(self.options.clearance) + unit )
spacing = self.svg.unittouu( str(self.options.spacing) + unit )
ring = 1
hingeOpt = self.options.hingeOpt
hingeThick = self.options.hingeThick
thumbTab = self.options.thumbTab
if inside: # if inside dimension selected correct values to outside dimension
# check input values mainly to avoid python errors
# TODO restrict values to *correct* solutions
# TODO -- Do what the origial author suggested I do. QUALITY!
if min(X,Y,Z)==0:
inkex.errormsg('Error: Dimensions must be non zero')
if max(X,Y,Z)>max(widthDoc,heightDoc)*10: # crude test
inkex.errormsg('Error: Dimensions Too Large')
if min(X,Y,Z)<3*nomTab:
inkex.errormsg('Error: Tab size too large')
if nomTab<thickness:
inkex.errormsg('Error: Tab size too small')
if thickness==0:
inkex.errormsg('Error: Thickness is zero')
if thickness>min(X,Y,Z)/3: # crude test
inkex.errormsg('Error: Material too thick')
if correction>min(X,Y,Z)/3: # crude test
inkex.errormsg('Error: Kerf/Clearence too large')
if spacing>max(X,Y,Z)*10: # crude test
inkex.errormsg('Error: Spacing too large')
if spacing<kerf: #if spacing is less then kerf, the laser cuts will overlap and blast meaningful material.
inkex.errormsg('Error: Spacing too small')
if error: exit()
# layout format:(rootx),(rooty),Xlength,Ylength,tabInfo
# root= (spacing,X,Y,Z) * values in tuple
# tabInfo= <abcd> 0=holes 1=tabs
if layout==0: # Diagramatic Layout TRBL
pieces=[ #center low row
#left middle row
#center middle row
#right middle row
[(3,1,0,1),(2,0,0,1),Z+(EllipseCircumference(X/2, Z/2)/4)+thickness,Y,0b1011,1],
#center top row
elif layout==1: # Inline(compact) Layout
#Front panel
#Sides with curves
#Long piece w/ hinge
[(5,3,0,1),(1,0,0,0),Z+(EllipseCircumference(X/2, Z/2)/4)+thickness,Y,0b1011,1]
for piece in pieces: # generate and draw each piece of the box
x=xs*spacing+xx*X+xy*Y+xz*Z # root x co-ord for piece
y=ys*spacing+yx*X+yy*Y+yz*Z # root y co-ord for piece
a=tabs>>3&1; b=tabs>>2&1; c=tabs>>1&1; d=tabs&1 # extract tab status for each side. It's a nasty packed binary flag format, but I'm not fixing it now.
longSide = 0
shortSide = 0
skew = 0
if piece[5] == 1:
longSide = Z
elif piece[5] < 0:
shortSide = Z
# generate and draw the sides of each piece
if piece[5] != -1:
drawS(side(x,y,d,a,-b,a,-thickness if a else thickness,dx,1,0,a,longSide)) # side a (top)
drawS(side(x,y,d,a,-b,a,-thickness if a else thickness,dx/2,1,0,a,-1)) # side a (top) when the top participates in a curve
if piece[5] != -1 and piece[5] != 1:
drawS(side(x+dx+skew,y,-b,a,-b,-c,thickness if b else -thickness,dy,0,1,b,shortSide, False if piece[5] != -2 else True, False if piece[5] != 1 else True)) # side b (right) except for side with living hinge or curves
elif piece[5] == -1:
drawS(side(x+dx+skew,y+dy,-b,-c,-b,a,thickness if b else -thickness,dy,0,-1,b,shortSide, True)) # side b (right) when the right side participates in a curve
#It is a cardnal sin to compare floats, so assume <0.0005 is 0 since the front end only gives you 3 digits of precision
if float(0.0005) <= float(self.options.thumbTab):
side(x+dx+skew,y,-b,a,-b,-c,thickness if b else -thickness,dy,0,1,b,shortSide, False, True, True) #The one call to side that doesn't actually draw. Instead, side draws boxes on its own
drawS(box(x+dx+skew,y+thickness,x+dx+skew+self.svg.unittouu( thumbTab + unit ),y+dy-thickness, True))
drawS(side(x+dx+skew,y,-b,a,-b,-c,thickness if b else -thickness,dy,0,1,b,shortSide, False, True)) #side b (right) on the right side of a living hinge
if piece[5] != -2:
drawS(side(x,y+dy,d,-c,-b,-c,thickness if c else -thickness,dx,1,0,c,longSide)) # side c (bottom)
drawS(side(x,y+dy,d,-c,-b,-c,thickness if c else -thickness,dx/2,1,0,c,-1)) # side c (bottom) when the bottom participates in a curve
drawS(side(x,y+dy,d,-c,d,a,-thickness if d else thickness,dy,0,-1,d,0)) # side d (left)
if piece[5] < 0:
draw_SVG_ellipse(x+(dx/2), y+(dy/2), (dx/2), (dy/2), [(1.5*math.pi), 0] if piece[5] == -1 else [0, 0.5*math.pi]) #draw the curve
if piece[5] == 1: #Piece should contain a living hinge
if hingeOpt == 0: #Traditional parallel slit
self.livingHinge2(x+(Z/2), y, x+(Z/2)+(EllipseCircumference(X/2, Z/2)/4), y + (dy), hingeThick)
elif hingeOpt == 1: #Single spiral
if not inside:
self.livingHinge3(x+(Z/2), y+thickness, x+(Z/2)+(EllipseCircumference(X/2, Z/2)/4), y + dy - thickness, 1, hingeThick)
self.livingHinge3(x+(Z/2), y + 2*thickness, x+(Z/2)+(EllipseCircumference(X/2, Z/2)/4), y + dy - 2*thickness, 1, hingeThick)
elif hingeOpt == 2: #Double spiral
self.livingHinge3(x+(Z/2), y+thickness, x+(Z/2)+(EllipseCircumference(X/2, Z/2)/4), y + (dy/2), 1, hingeThick)
self.livingHinge3(x+(Z/2), y+(dy/2), x+(Z/2)+(EllipseCircumference(X/2, Z/2)/4), y + dy - thickness, -1, hingeThick)
elif hingeOpt == 3 or hingeOpt == 4: #Both snake-based designs
self.livingHinge4(x+(Z/2), y, x+(Z/2)+(EllipseCircumference(X/2, Z/2)/4), y + (dy), False if hingeOpt == 3 else True, 0, hingeThick)
elif hingeOpt == 5: #Double snake design
self.livingHinge4(x+(Z/2), y, x+(Z/2)+EllipseCircumference(X/2, Z/2)/4, y + (dy/2) + thickness, True, 0, hingeThick) #Add thickness as a cheat so design 4 doesn't have to know if it's a short or long variant
self.livingHinge4(x+(Z/2), y + (dy/2) - thickness, (x+(Z/2)+(EllipseCircumference(X/2, Z/2)/4)), y + dy, True, 1, hingeThick)
if __name__ == '__main__':