Functions for generating G-Code for mitered box panels

miter_panels.py

from math import cos, sin, tan, atan2, atan, pi

def gx(n, x=None,y=None,z=None, f=None):
	retval = ['G%d' % n]
	for a,b in zip(('X','Y','Z','F'), (x, y, z, f)):
		if b is not None:
			if a == 'F':
				b *= 60.0 # Feedrates in ipm not ips
			retval.append(' %s%0.4f' % (a,b))
	return ''.join(retval)

def g0(x=None,y=None,z=None):
	return gx(0,x,y,z)

def g1(x=None,y=None,z=None, f=None):
	return gx(1,x,y,z,f)

def offset(line, amount):
	a = line[0]
	b = line[1]
	theta = atan2(b[1]-a[1],b[0]-a[0])+pi/2
	ap = (a[0]+amount*cos(theta), a[1]+amount*sin(theta))
	bp = (b[0]+amount*cos(theta), b[1]+amount*sin(theta))
	return ap,bp

def create_miter(a,b,angle=45,step=0.005,thickness=0.5,pullup=0.25,feedrate=4.0):
	g = [g0(*a),g1(z=0,f=feedrate)]
	z = 0
	l = 0
	#print "creating miter for " + str(a) + " -> " + str(b)
	line = (a,b)
	direction = True
	while z > -thickness:
		a,b = line
		if(direction):
			g.append(g1(*b))
		else:
			g.append(g1(*a))
		line = offset(line, step)
		a,b = line
		z -= step*tan(angle*pi/180)
		# Step over
		if(direction):
			g.append(g1(*b,z=z))
		else:
			g.append(g1(*a,z=z))
		direction = not direction
	g.append(g0(z=pullup))
	return g

def create_cutout(sides, thickness=0.5, pullup=0.25, feedrate=1.5, pass_depth=0.125):
	start = sides[0][0]
	g = [g0(*start),g1(z=0,f=feedrate)]
	z = 0;
	while True:
		z -= pass_depth
		if z < -thickness:
			z = -thickness
		g.append(g1(z=z,f=feedrate))
		for a,b in sides:
			g.append(g1(*b,f=feedrate))
		if z <= -thickness:
			break
	g.append(g0(z=pullup))
	return g

class Panel(object):
	def __init__(self, w, h, thickness):
		self.w = w
		self.h = h
		self.miters = {}
		self.cutter = 0.125
		self.cut_speed = 2.0
		self.miter_speed = 4.0
		self.safe_pullup = 0.25
		self.thickness = thickness
		self.miter_step = 0.005
		self.x = 0
		self.y = 0

	def miter(self, side, angle):
		self.miters[side] = angle

	def translate(self, dx=0, dy=0):
		self.x+=dx
		self.y+=dy

	def render(self):
		cr = self.cutter/2.0

		corners = [
			[self.x-cr, self.y+self.h+cr],
			[self.x+self.w+cr, self.y+self.h+cr],
			[self.x+self.w+cr, self.y-cr],
			[self.x-cr, self.y-cr]
		]

		side_names = ['w','n','e','s']
		sides = [(corners[i-1],corners[i]) for i in range(4)]
		sides_dict = dict(zip(side_names, sides))

		miters = []

		# Create miters
		for name, angle in self.miters.items():
			line = sides_dict[name]
			miter = create_miter(line[0],line[1],
				angle=angle, 
				step=self.miter_step,
				thickness=self.thickness,
				pullup=self.safe_pullup,
				feedrate=self.miter_speed
			)
			miters.append(miter)

		if 'n' in self.miters:
			miter_length = self.thickness*1.0/tan(self.miters['n']*pi/180.0)
			corners[0][1] += miter_length
			corners[1][1] += miter_length

		if 'e' in self.miters:
			miter_length = self.thickness*1.0/tan(self.miters['e']*pi/180.0)
			corners[1][0] += miter_length
			corners[2][0] += miter_length

		if 's' in self.miters:
			miter_length = self.thickness*1.0/tan(self.miters['s']*pi/180.0)
			corners[2][1] -= miter_length
			corners[3][1] -= miter_length

		if 'w' in self.miters:
			miter_length = self.thickness*1.0/tan(self.miters['w']*pi/180.0)
			corners[3][0] -= miter_length
			corners[0][0] -= miter_length

		sides = [(corners[i-1],corners[i]) for i in range(4)]
		sides_dict = dict(zip(side_names, sides))

		cutout = create_cutout(sides,thickness=self.thickness)
		
		retval = []
		for miter in miters:
			retval.extend(miter)
		retval.extend(cutout)

		return retval


if __name__ == "__main__":
	# Bottom Panel(1,5.5,0.5)

	bottom = Panel(1,5.5, 0.5)
	bottom.miter_step = 0.010
	bottom.miter_speed = 5.0
	bottom.miter('w', 45)
	bottom.miter('e', 45)

	g = [
		'G20',
		g0(z=0.5),
		'M4',
		'G4 P3'
	]
	g.extend(bottom.render())

	with open('bottom.g', 'w') as fp:
		fp.write('\n'.join(g))

	side = Panel(3.5,5.5, 0.5)
	side.miter_step = 0.010
	side.miter_speed = 5.0
	side.miter('w', 45)

	g = [
		'G20',
		g0(z=0.5),
		'M4',
		'G4 P3'
	]
	g.extend(side.render())

	with open('side.g', 'w') as fp:
		fp.write('\n'.join(g))


	roof = Panel(6.25,8, 0.5)
	roof.miter_step = 0.010
	roof.miter_speed = 5.0
	roof.miter('e', 45)

	g = [
		'G20',
		g0(z=0.5),
		'M4',
		'G4 P3'
	]
	g.extend(roof.render())

	with open('roof.g', 'w') as fp:
		fp.write('\n'.join(g))