Files
create/src/Mod/Path/PathScripts/PathGeom.py
Markus Lampert cb85072bbd Fixed alignment issue and unit tests.
The trick is really to over-extend edges before creationg shapes for the common operation, and trying to avoid alignment of the edge with the cone's seam.
2017-01-02 17:34:36 -08:00

370 lines
16 KiB
Python

# -*- coding: utf-8 -*-
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# * Copyright (c) 2016 sliptonic <shopinthewoods@gmail.com> *
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# * This program is free software; you can redistribute it and/or modify *
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# * This program is distributed in the hope that it will be useful, *
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# * GNU Library General Public License for more details. *
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import FreeCAD
import math
import Part
import Path
from FreeCAD import Vector
class Side:
"""Class to determine and define the side a Path is on, or Vectors are in relation to each other."""
Left = +1
Right = -1
Straight = 0
On = 0
@classmethod
def toString(cls, side):
"""(side)
Returns a string representation of the enum value."""
if side == cls.Left:
return 'Left'
if side == cls.Right:
return 'Right'
return 'On'
@classmethod
def of(cls, ptRef, pt):
"""(ptRef, pt)
Determine the side of pt in relation to ptRef.
If both Points are viewed as vectors with their origin in (0,0,0)
then the two vectors are either form a straigt line (On) or pt
lies in the left or right hemishpere in regards to ptRef."""
d = -ptRef.x*pt.y + ptRef.y*pt.x
if d < 0:
return cls.Left
if d > 0:
return cls.Right
return cls.Straight
class PathGeom:
"""Class to transform Path Commands into Edges and Wire and back again.
The interface might eventuallly become part of Path itself."""
CmdMoveRapid = ['G0', 'G00']
CmdMoveStraight = ['G1', 'G01']
CmdMoveCW = ['G2', 'G02']
CmdMoveCCW = ['G3', 'G03']
CmdMoveArc = CmdMoveCW + CmdMoveCCW
CmdMove = CmdMoveStraight + CmdMoveArc
@classmethod
def isRoughly(cls, float1, float2, error=0.0000001):
"""(float1, float2, [error=0.0000001])
Returns true if the two values are the same within a given error."""
return math.fabs(float1 - float2) <= error
@classmethod
def pointsCoincide(cls, p1, p2, error=0.0000001):
"""(p1, p2, [error=0.0000001])
Return True if two points are roughly identical (see also isRoughly)."""
return cls.isRoughly(p1.x, p2.x, error) and cls.isRoughly(p1.y, p2.y, error) and cls.isRoughly(p1.z, p2.z, error)
@classmethod
def edgesMatch(cls, e0, e1, error=0.0000001):
"""(e0, e1, [error=0.0000001]
Return true if the edges start and end at the same point and have the same type of curve."""
if type(e0.Curve) != type(e1.Curve):
return False
if not cls.pointsCoincide(e0.valueAt(e0.FirstParameter), e1.valueAt(e1.FirstParameter)):
return False
if not cls.pointsCoincide(e0.valueAt(e0.LastParameter), e1.valueAt(e1.LastParameter)):
return False
return True
@classmethod
def edgeConnectsTo(cls, edge, vector):
"""(edge, vector)
Returns True if edge connects to given vector."""
return cls.pointsCoincide(edge.valueAt(edge.FirstParameter), vector) or cls.pointsCoincide(edge.valueAt(edge.LastParameter), vector)
@classmethod
def getAngle(cls, vector):
"""(vector)
Returns the angle [-pi,pi] of a vector using the X-axis as the reference.
Positive angles for vertexes in the upper hemishpere (positive y values)
and negative angles for the lower hemishpere."""
a = vector.getAngle(FreeCAD.Vector(1,0,0))
if vector.y < 0:
return -a
return a
@classmethod
def diffAngle(cls, a1, a2, direction = 'CW'):
"""(a1, a2, [direction='CW'])
Returns the difference between two angles (a1 -> a2) into a given direction."""
if direction == 'CW':
while a1 < a2:
a1 += 2*math.pi
a = a1 - a2
else:
while a2 < a1:
a2 += 2*math.pi
a = a2 - a1
return a
@classmethod
def commandEndPoint(cls, cmd, defaultPoint = Vector(), X='X', Y='Y', Z='Z'):
"""(cmd, [defaultPoint=Vector()], [X='X'], [Y='Y'], [Z='Z'])
Extracts the end point from a Path Command."""
x = cmd.Parameters.get(X, defaultPoint.x)
y = cmd.Parameters.get(Y, defaultPoint.y)
z = cmd.Parameters.get(Z, defaultPoint.z)
return FreeCAD.Vector(x, y, z)
@classmethod
def xy(cls, point):
"""(point)
Convenience function to return the projection of the Vector in the XY-plane."""
return Vector(point.x, point.y, 0)
@classmethod
def cmdsForEdge(cls, edge, flip = False, useHelixForBSpline = True):
"""(edge, flip = False, useHelixForBSpline = True) -> List(Path.Command)
Returns a list of Path.Command representing the given edge.
If flip is True the edge is considered to be backwards.
If useHelixForBSpline is True an Edge based on a BSplineCurve is considered
to represent a helix and results in G2 or G3 command. Otherwise edge has
no direct Path.Command mapping and will be approximated by straight segments.
Approximation is also the approach for edges that are neither straight lines
nor arcs (nor helixes)."""
pt = edge.valueAt(edge.LastParameter) if not flip else edge.valueAt(edge.FirstParameter)
params = {'X': pt.x, 'Y': pt.y, 'Z': pt.z}
if type(edge.Curve) == Part.Line or type(edge.Curve) == Part.LineSegment:
commands = [Path.Command('G1', params)]
else:
if not flip:
p1 = edge.valueAt(edge.FirstParameter)
p3 = pt
else:
p1 = pt
p3 = edge.valueAt(edge.LastParameter)
p2 = edge.valueAt((edge.FirstParameter + edge.LastParameter)/2)
if type(edge.Curve) == Part.Circle or (useHelixForBSpline and type(edge.Curve) == Part.BSplineCurve):
if Side.Left == Side.of(p2 - p1, p3 - p2):
cmd = 'G3'
else:
cmd = 'G2'
#print("**** (%.2f, %.2f, %.2f) - (%.2f, %.2f, %.2f) - (%.2f, %.2f, %.2f)" % (p1.x, p1.y, p1.z, p2.x, p2.y, p2.z, p3.x, p3.y, p3.z))
pd = Part.Circle(PathGeom.xy(p1), PathGeom.xy(p2), PathGeom.xy(p3)).Center
pa = PathGeom.xy(p1)
pb = PathGeom.xy(p2)
pc = PathGeom.xy(p3)
#print("**** (%.2f, %.2f, %.2f) - (%.2f, %.2f, %.2f)" % (pa.x, pa.y, pa.z, pc.x, pc.y, pc.z))
#print("**** (%.2f, %.2f, %.2f) - (%.2f, %.2f, %.2f)" % (pb.x, pb.y, pb.z, pd.x, pd.y, pd.z))
offset = Part.Circle(PathGeom.xy(p1), PathGeom.xy(p2), PathGeom.xy(p3)).Center - p1
#print("**** (%.2f, %.2f, %.2f)" % (offset.x, offset.y, offset.z))
params.update({'I': offset.x, 'J': offset.y, 'K': (p3.z - p1.z)/2})
commands = [ Path.Command(cmd, params) ]
else:
eStraight = Part.Edge(Part.LineSegment(p1, p3))
esP2 = eStraight.valueAt((eStraight.FirstParameter + eStraight.LastParameter)/2)
deviation = (p2 - esP2).Length
if cls.isRoughly(deviation, 0):
return [ Path.Command('G1', {'X': p3.x, 'Y': p3.y, 'Z': p3.z}) ]
# at this point pixellation is all we can do
commands = []
segments = int(math.ceil((deviation / eStraight.Length) * 1000))
#print("**** pixellation with %d segments" % segments)
dParameter = (edge.LastParameter - edge.FirstParameter) / segments
for i in range(0, segments):
if flip:
p = edge.valueAt(edge.LastParameter - (i + 1) * dParameter)
else:
p = edge.valueAt(edge.FirstParameter + (i + 1) * dParameter)
cmd = Path.Command('G1', {'X': p.x, 'Y': p.y, 'Z': p.z})
#print("***** %s" % cmd)
commands.append(cmd)
#print commands
return commands
@classmethod
def edgeForCmd(cls, cmd, startPoint):
"""(cmd, startPoint).
Returns an Edge representing the given command, assuming a given startPoint."""
endPoint = cls.commandEndPoint(cmd, startPoint)
if (cmd.Name in cls.CmdMoveStraight) or (cmd.Name in cls.CmdMoveRapid):
if cls.pointsCoincide(startPoint, endPoint):
return None
return Part.Edge(Part.LineSegment(startPoint, endPoint))
if cmd.Name in cls.CmdMoveArc:
center = startPoint + cls.commandEndPoint(cmd, Vector(0,0,0), 'I', 'J', 'K')
A = cls.xy(startPoint - center)
B = cls.xy(endPoint - center)
d = -B.x * A.y + B.y * A.x
if d == 0:
# we're dealing with half a circle here
angle = cls.getAngle(A) + math.pi/2
if cmd.Name in cls.CmdMoveCW:
angle -= math.pi
else:
C = A + B
angle = cls.getAngle(C)
R = A.Length
#print("arc: p1=(%.2f, %.2f) p2=(%.2f, %.2f) -> center=(%.2f, %.2f)" % (startPoint.x, startPoint.y, endPoint.x, endPoint.y, center.x, center.y))
#print("arc: A=(%.2f, %.2f) B=(%.2f, %.2f) -> d=%.2f" % (A.x, A.y, B.x, B.y, d))
#print("arc: R=%.2f angle=%.2f" % (R, angle/math.pi))
if startPoint.z == endPoint.z:
midPoint = center + FreeCAD.Vector(math.cos(angle), math.sin(angle), 0) * R
return Part.Edge(Part.Arc(startPoint, midPoint, endPoint))
# It's a Helix
#print('angle: A=%.2f B=%.2f' % (cls.getAngle(A)/math.pi, cls.getAngle(B)/math.pi))
if cmd.Name in cls.CmdMoveCW:
cw = True
else:
cw = False
angle = cls.diffAngle(cls.getAngle(A), cls.getAngle(B), 'CW' if cw else 'CCW')
height = endPoint.z - startPoint.z
pitch = height * math.fabs(2 * math.pi / angle)
if angle > 0:
cw = not cw
#print("Helix: R=%.2f h=%.2f angle=%.2f pitch=%.2f" % (R, height, angle/math.pi, pitch))
helix = Part.makeHelix(pitch, height, R, 0, not cw)
helix.rotate(Vector(), Vector(0,0,1), 180 * cls.getAngle(A) / math.pi)
e = helix.Edges[0]
helix.translate(startPoint - e.valueAt(e.FirstParameter))
return helix.Edges[0]
return None
@classmethod
def wireForPath(cls, path, startPoint = FreeCAD.Vector(0, 0, 0)):
"""(path, [startPoint=Vector(0,0,0)])
Returns a wire representing all move commands found in the given path."""
edges = []
rapid = []
if hasattr(path, "Commands"):
for cmd in path.Commands:
edge = cls.edgeForCmd(cmd, startPoint)
if edge:
if cmd.Name in cls.CmdMoveRapid:
rapid.append(edge)
edges.append(edge)
startPoint = cls.commandEndPoint(cmd, startPoint)
return (Part.Wire(edges), rapid)
@classmethod
def wiresForPath(cls, path, startPoint = FreeCAD.Vector(0, 0, 0)):
"""(path, [startPoint=Vector(0,0,0)])
Returns a collection of wires, each representing a continuous cutting Path in path."""
wires = []
if hasattr(path, "Commands"):
edges = []
for cmd in path.Commands:
if cmd.Name in cls.CmdMove:
edges.append(cls.edgeForCmd(cmd, startPoint))
startPoint = cls.commandEndPoint(cmd, startPoint)
elif cmd.Name in cls.CmdMoveRapid:
wires.append(Part.Wire(edges))
edges = []
startPoint = cls.commandEndPoint(cmd, startPoint)
if edges:
wires.append(Part.Wire(edges))
return wires
@classmethod
def arcToHelix(cls, edge, z0, z1):
"""(edge, z0, z1)
Assuming edge is an arc it'll return a helix matching the arc starting at z0 and rising/falling to z1."""
p1 = edge.valueAt(edge.FirstParameter)
p2 = edge.valueAt(edge.LastParameter)
cmd = cls.cmdsForEdge(edge)[0]
params = cmd.Parameters
params.update({'Z': z1, 'K': (z1 - z0)/2})
command = Path.Command(cmd.Name, params)
#print("- (%.2f, %.2f, %.2f) - (%.2f, %.2f, %.2f): %.2f:%.2f" % (edge.Vertexes[0].X, edge.Vertexes[0].Y, edge.Vertexes[0].Z, edge.Vertexes[1].X, edge.Vertexes[1].Y, edge.Vertexes[1].Z, z0, z1))
#print("- %s -> %s" % (cmd, command))
return cls.edgeForCmd(command, FreeCAD.Vector(p1.x, p1.y, z0))
@classmethod
def helixToArc(cls, edge, z = 0):
"""(edge, z=0)
Returns the projection of the helix onto the XY-plane with a given offset."""
p1 = edge.valueAt(edge.FirstParameter)
p2 = edge.valueAt((edge.FirstParameter + edge.LastParameter)/2)
p3 = edge.valueAt(edge.LastParameter)
p01 = FreeCAD.Vector(p1.x, p1.y, z)
p02 = FreeCAD.Vector(p2.x, p2.y, z)
p03 = FreeCAD.Vector(p3.x, p3.y, z)
return Part.Edge(Part.Arc(p01, p02, p03))
@classmethod
def splitArcAt(cls, edge, pt):
"""(edge, pt)
Returns a list of 2 edges which together form the original arc split at the given point.
The Vector pt has to represnt a point on the given arc."""
p1 = edge.valueAt(edge.FirstParameter)
p2 = pt
p3 = edge.valueAt(edge.LastParameter)
edges = []
p = edge.Curve.parameter(p2)
#print("splitArcAt(%.2f, %.2f, %.2f): %.2f - %.2f - %.2f" % (pt.x, pt.y, pt.z, edge.FirstParameter, p, edge.LastParameter))
p12 = edge.Curve.value((edge.FirstParameter + p)/2)
p23 = edge.Curve.value((p + edge.LastParameter)/2)
#print("splitArcAt: p12=(%.2f, %.2f, %.2f) p23=(%.2f, %.2f, %.2f)" % (p12.x, p12.y, p12.z, p23.x, p23.y, p23.z))
edges.append(Part.Edge(Part.Arc(p1, p12, p2)))
edges.append(Part.Edge(Part.Arc(p2, p23, p3)))
return edges
@classmethod
def splitEdgeAt(cls, edge, pt):
"""(edge, pt)
Returns a list of 2 edges, forming the original edge split at the given point.
The results are undefined if the Vector representing the point is not part of the edge."""
# I could not get the OCC parameterAt and split to work ...
# pt HAS to be on the edge, otherwise the results are undefined
p1 = edge.valueAt(edge.FirstParameter)
p2 = pt
p3 = edge.valueAt(edge.LastParameter)
edges = []
if type(edge.Curve) == Part.Line or type(edge.Curve) == Part.LineSegment:
# it's a line
return [Part.Edge(Part.LineSegment(p1, p2)), Part.Edge(Part.LineSegment(p2, p3))]
elif type(edge.Curve) == Part.Circle:
# it's an arc
return cls.splitArcAt(edge, pt)
else:
# it's a helix
arc = cls.helixToArc(edge, 0)
aes = cls.splitArcAt(arc, FreeCAD.Vector(pt.x, pt.y, 0))
return [cls.arcToHelix(aes[0], p1.z, p2.z), cls.arcToHelix(aes[1], p2.z, p3.z)]