sfc/slicer.py: cleanup and debugging; add various alignment and transformation options

sfc/slicer.py

@@ -25,8 +25,14 @@ from math import hypot
 
 epsilon = 0.0001	# acceptable math rounding error and slicing offset
 mech_eps = 0.01		# acceptable mechanical deviation
-margin = None		# draw a workpiece at the specified xy distance around
-			# the model (default: none)
+margin = None		# draw a rectangular workpiece at the specified xy
+			# distance around the model (default: none)
+z_step = None		# maximum Z step (default: unlimited)
+flip = False		# flip around X center (default: don't)
+height = None		# height of the workpiece above the Z plane (can be
+			# negative). Default: use model dimensions.
+align_top = None	# align the Z position of the model to the workpiece
+align_bottom = None
 
 
 def dist(a, b):
@@ -35,13 +41,58 @@ def dist(a, b):
 	return hypot(pa[0] - pb[0], pa[1] - pb[1])
 
 
-def print_vec(v):
+def print_vec(v, z):
 	p = v.Point
-	print p[0], " ", p[1], " ", p[2] - epsilon
+	print p[0], " ", p[1], " ", z
+
+
+# Make a vector from a point. While we're at it, also apply flipping (if
+# requested).
+
+def vec(p):
+	if flip:
+		return Base.Vector(p[0],
+		    bb.YMax - p[1] + bb.YMin, bb.ZMax - p[2] + bb.ZMin)
+	else:
+		return Base.Vector(p[0], p[1], p[2])
+
+#
+# Dump the current Z level (plateau or intermediate level).
+#
+
+
+def dump_level(wires, z):
+	print "# level z = ", z
+
+	if margin is not None:
+		print bb.XMin - margin, " ", bb.YMin - margin, " ", z
+		print bb.XMax + margin, " ", bb.YMin - margin, " ", z
+		print bb.XMax + margin, " ", bb.YMax + margin, " ", z
+		print bb.XMin - margin, " ", bb.YMax + margin, " ", z
+		print bb.XMin - margin, " ", bb.YMin - margin, " ", z
+		print
+
+	for wire in wires:
+		print "# wire = ", wire
+		first = None
+		last = None
+		for e in wire.Edges:
+			v = e.Vertexes[0]
+			if first is None:
+				first = v
+			if last is None or dist(v, last) >= mech_eps:
+				print_vec(v, z)
+			last = v
+		if first is not None:
+			print_vec(first, z)
+			print
+	print
 
 
 def usage():
-	print >>sys.stderr, "usage:", sys.argv[0], "file.stl"
+	print >>sys.stderr, "usage:", sys.argv[0], \
+	    "[-a (top|bottom)(+|-)offset] [-f] [-h height]" + \
+	    "\t[-b piece_distance] [-s max_step] file.stl"
 	sys.exit(1)
 
 
@@ -54,10 +105,23 @@ stdout = os.dup(1)
 os.dup2(2, 1)
 sys.stdout = os.fdopen(stdout, "w")
 
-opts, args = getopt.getopt(sys.argv[1:], "b:")
+opts, args = getopt.getopt(sys.argv[1:], "a:fh:p:s:")
 for opt, arg in opts:
-	if opt == "-b":
+	if opt == "-a":
+		if arg[0:3] == "top":
+			align_top = float(arg[3:])
+		elif arg[0:6] == "bottom":
+			align_bottom = float(arg[6:])
+		else:
+			usage()
+	elif opt == "-f":
+		flip = True
+	elif opt == "-h":
+		height = float(arg)
+	elif opt == "-p":
 		margin = float(arg)
+	elif opt == "-s":
+		z_step = float(arg)
 	else:
 		assert False
 
@@ -65,10 +129,11 @@ if len(args) != 1:
 	usage()
 
 #
-# Read the STL mesh
+# Read the STL mesh and determine its bounding box
 #
 
 mesh = Mesh.Mesh(args[0])
+bb = mesh.BoundBox
 
 #
 # The 2.5D model consists of "plateaus" (facets parallel to the xy plane) and
@@ -91,10 +156,8 @@ for facet in mesh.Facets:
 		if nz > epsilon:
 			inclined += 1
 			max_nz = max(max_nz, nz)
-		v1 = Base.Vector(facet.Points[0])
-		v2 = Base.Vector(facet.Points[1])
-		v3 = Base.Vector(facet.Points[1])
-		vert.addFacet(v1, v2, v3)
+		vert.addFacet(vec(facet.Points[0]), vec(facet.Points[1]),
+		    vec(facet.Points[2]))
 
 if inclined:
 	print >>sys.stderr	# FreeCAD progress reporting messes up newlines
@@ -120,41 +183,44 @@ for z in sorted(z_raw.keys(), reverse = True):
 #
 
 shape = Part.Shape()
-shape.makeShapeFromMesh(mesh.Topology, mech_eps)
-bb = shape.BoundBox
+shape.makeShapeFromMesh(vert.Topology, mech_eps)
+
+z_off = 0
+if height is not None:
+	if align_top is not None:
+		z_off = align_top - bb.ZMax
+		if height > 0:
+			z_off += height
+	if align_bottom is not None:
+		z_off = align_bottom - bb.ZMin
+		if height < 0:
+			z_off += height
 
 #
 # Iterate over all plateaus and determine how they intersect with the walls.
 # For this, we add a small offset to the z position so that we intersect above
 # the plateau.
 #
+# We advance by at most z_step and insert intermediate layers if needed. 
+#
 
-for z in z_levels:
-	print "# level z = ", z
+if height is not None and height > 0:
+	last_z = height 
+else:
+	last_z = None
+if height is not None and height < 0 and z_levels[-1] > height:
+	z_levels.append(height)
 	
-	if margin is not None:
-		print bb.XMin - margin, " ", bb.YMin - margin, " ", z
-		print bb.XMax + margin, " ", bb.YMin - margin, " ", z
-		print bb.XMax + margin, " ", bb.YMax + margin, " ", z
-		print bb.XMin - margin, " ", bb.YMax + margin, " ", z
-		print bb.XMin - margin, " ", bb.YMin - margin, " ", z
-		print
-
-	for wire in shape.slice(Base.Vector(0, 0, 1), z + epsilon):
-		print "# wire = ", wire
-		first = None
-		last = None
-		for e in wire.Edges:
-			v = e.Vertexes[0]
-			if first is None:
-				first = v
-			if last is None or dist(v, last) >= mech_eps:
-				print_vec(v)
-			last = v
-		if first is not None:
-			print_vec(first)
-			print
-	print
+for next_z in z_levels:
+	wires = shape.slice(Base.Vector(0, 0, 1), next_z + epsilon)
+	if z_step is None or last_z is None or last_z + z_step >= next_z:
+		dump_level(wires, next_z + z_off)
+	else:
+		d = next_z - last_z
+		n = (d // z_step) + 1
+		for i in range(0, n):
+			dump_level(wires, last_z + (i + 1) * (d / n) + z_off)
+	last_z = next_z
 	
 #
 # That's all, folks !