src/Mod/CAM/Path/Op/Vcarve.py

# SPDX-License-Identifier: LGPL-2.1-or-later

# ***************************************************************************
# *   Copyright (c) 2020 sliptonic <shopinthewoods@gmail.com>               *
# *                                                                         *
# *   This program is free software; you can redistribute it and/or modify  *
# *   it under the terms of the GNU Lesser General Public License (LGPL)    *
# *   as published by the Free Software Foundation; either version 2 of     *
# *   the License, or (at your option) any later version.                   *
# *   for detail see the LICENCE text file.                                 *
# *                                                                         *
# *   This program is distributed in the hope that it will be useful,       *
# *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
# *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
# *   GNU Library General Public License for more details.                  *
# *                                                                         *
# *   You should have received a copy of the GNU Library General Public     *
# *   License along with this program; if not, write to the Free Software   *
# *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  *
# *   USA                                                                   *
# *                                                                         *
# ***************************************************************************

import FreeCAD
import Part
import Path
import Path.Op.Base as PathOp
import Path.Op.EngraveBase as PathEngraveBase
import PathScripts.PathUtils as PathUtils
import math
from PySide.QtCore import QT_TRANSLATE_NOOP

__doc__ = "Class and implementation of CAM Vcarve operation"

PRIMARY = 0
SECONDARY = 1
EXTERIOR1 = 2
EXTERIOR2 = 3
COLINEAR = 4
TWIN = 5
BORDERLINE = 6

# There is a bug in logging library. To enable debugging - set True also in Gui/Vcarve.py

if False:
    Path.Log.setLevel(Path.Log.Level.DEBUG, Path.Log.thisModule())
    Path.Log.trackModule(Path.Log.thisModule())
else:
    Path.Log.setLevel(Path.Log.Level.INFO, Path.Log.thisModule())


translate = FreeCAD.Qt.translate


def _collectVoronoiWires(vd):
    edges = [e for e in vd.Edges if e.Color == PRIMARY]
    vertex = {}
    for e in edges:
        for v in e.Vertices:
            i = v.Index
            j = vertex.get(i, [])
            j.append(e)
            vertex[i] = j

    # knots are the start and end points of a wire
    knots = [i for i in vertex if len(vertex[i]) == 1]
    knots.extend([i for i in vertex if len(vertex[i]) > 2])
    if len(knots) == 0:
        for i in vertex:
            if len(vertex[i]) > 0:
                knots.append(i)
                break

    def consume(v, edge):
        vertex[v] = [e for e in vertex[v] if e.Index != edge.Index]
        return len(vertex[v]) == 0

    def traverse(vStart, edge, edges):
        if vStart == edge.Vertices[0].Index:
            vEnd = edge.Vertices[1].Index
            edges.append(edge)
        else:
            vEnd = edge.Vertices[0].Index
            edges.append(edge.Twin)

        consume(vStart, edge)
        if consume(vEnd, edge):
            return None
        return vEnd

    wires = []
    while knots:
        we = []
        vFirst = knots[0]
        vStart = vFirst
        vLast = vFirst
        if len(vertex[vStart]):
            while vStart is not None:
                vLast = vStart
                edges = vertex[vStart]
                if len(edges) > 0:
                    edge = edges[0]
                    vStart = traverse(vStart, edge, we)
                else:
                    vStart = None
            wires.append(we)
        if len(vertex[vFirst]) == 0:
            knots = [v for v in knots if v != vFirst]
        if len(vertex[vLast]) == 0:
            knots = [v for v in knots if v != vLast]
    return wires


def _sortVoronoiWires(wires, start=FreeCAD.Vector(0, 0, 0)):
    def closestTo(start, point):
        p = None
        length = None
        for i in point:
            if length is None or length > start.distanceToPoint(point[i]):
                length = start.distanceToPoint(point[i])
                p = i
        return (p, length)

    begin = {}
    end = {}

    for i, w in enumerate(wires):
        begin[i] = w[0].Vertices[0].toPoint()
        end[i] = w[-1].Vertices[1].toPoint()

    result = []
    while begin:
        (bIdx, bLen) = closestTo(start, begin)
        (eIdx, eLen) = closestTo(start, end)
        if bLen < eLen:
            result.append(wires[bIdx])
            start = end[bIdx]
            del begin[bIdx]
            del end[bIdx]
        else:
            result.append([e.Twin for e in reversed(wires[eIdx])])
            start = begin[eIdx]
            del begin[eIdx]
            del end[eIdx]

    return result


def getReversedEdge(edge):
    # returns a reversed edge (copy of original edge)
    curve = edge.Curve
    first = edge.FirstParameter
    last = edge.LastParameter
    curve_c = curve.copy()
    curve_c.reverse()
    return Part.Edge(curve_c, curve_c.reversedParameter(last), curve_c.reversedParameter(first))


def generateVirtualBackTrackEdges(positionHistory, nextEdge, tolerance) -> list:
    """
    Generate a list of "virtual edges" to backtrack using normal G1 moves instead lifting
    toolbit and repositioning using G0 to get to beginning of nextEdge.
    Those virtual edges are either already carved or are part of nextEdge anyway so it's safe
    to follow them without lifting toolbit. This approach makes carving a lot of faster.
    """

    if not positionHistory or len(positionHistory) < 2:
        return []

    backTrackEdges = []

    currentPosition = positionHistory[-1]
    previousPosition = positionHistory[-2]

    nextEdgeStart = nextEdge.valueAt(nextEdge.FirstParameter)
    nextEdgeEnd = nextEdge.valueAt(nextEdge.LastParameter)

    # Scenario 1
    #
    # in some cases travelling between wires looks like that:
    # A ========= B ------- D
    #             |
    #             C
    #
    # we follow first wire from A to B - new wire starts at C and goes through B -> D
    # Repositioning to position C using G0 command does not make sense and it's slow
    # We can insert "virtual" edge B->C at the beginning of a second wire to make
    # continuous CNC head movement
    #

    if nextEdgeEnd.isEqual(currentPosition, tolerance):
        # virtual edge is "reversed"
        virtualEdge = Part.Edge(Part.LineSegment(nextEdgeEnd, nextEdgeStart))
        backTrackEdges.append(virtualEdge)

    # Scenario 2
    # next edge has common node with previous position but it's reversed
    #  A     C
    #   \   //
    #    \ //
    #     B
    # We went from B to C and next wire edge starts at A and goes back to B
    # Normally we would G0 jump from C to A and start from there,
    # but we can go back from C to B and then to A (by adding extra edge which
    # is reversed A->B edge).

    elif nextEdgeEnd.isEqual(previousPosition, tolerance):
        # travel back to the previous toolbit position
        virtualEdge = Part.Edge(Part.LineSegment(currentPosition, previousPosition))
        backTrackEdges.append(virtualEdge)
        # instead of G0 - just carve the edge in reverse direction
        backTrackEdges.append(getReversedEdge(nextEdge))

    return backTrackEdges


def canSkipRepositioning(positionHistory, newPosition, tolerance):
    """
    Calculate if it makes sense to raise head to safe height and reposition before
    starting to cut another edge
    """

    if not positionHistory:
        return False

    currentPosition = positionHistory[-1]
    previousPosition = positionHistory[-2]

    # get vertex position on X/Y plane only
    v0 = FreeCAD.Base.Vector(currentPosition.x, currentPosition.y)
    v1 = FreeCAD.Base.Vector(newPosition.x, newPosition.y)

    # do not bother with G0 if new and current position differ by less than 0.5 mm in X/Y
    if v0.distanceToPoint(v1) <= 0.5:
        return True

    # if new position is same as previous head position we can essentially
    # go back traversing same edge. This is handy with short "detour" edges like that:
    #
    #      A--------------B===============C
    #                     |
    #                     D
    # We are travelling wire from A -> B -> D within first wire and ending at D. New wire starts with edge going from
    # B to C. We don't need to G0 to point B, we can skip positioning because if we travel G1 move from D to B we will follow already
    # carved path

    if newPosition.isEqual(previousPosition, tolerance):
        return True

    return False


class _Geometry(object):
    """POD class so the limits only have to be calculated once."""

    def __init__(self, zStart, zStop, zScale, zStepDown):
        self.start = zStart
        self.stop = zStop
        self.scale = zScale
        self.stepDown = zStepDown
        self.stepDownPass = 1

        # offset is used in finishing passes to override
        # any calculated vcarving depths. Usually going deeper 0.1-0.2 mm on finishing pass can help
        # remove "fuzzy skin" or other imperfections.
        self.offset = 0

    def incrementStepDownDepth(self, maximumUsableDepth):
        """
        Increase stepDown depth before starting new carving pass.
        :returns: True if successful, False if maximum depth achieved
        """

        # do not allow one to increase depth if we are already at stop depth
        if self.maximumDepth == self.stop:
            return False

        # do not allow one to increase depth if we are already at
        # maximum usable depth

        if self.maximumDepth <= maximumUsableDepth:
            return False

        self.stepDownPass += 1
        return True

    @property
    def maximumDepth(self):
        """
        Return maximum vcarving depth computed from step down setting and pass number
        """

        if self.stepDown == 0:
            return self.stop

        return max(self.stop, self.start - (self.stepDownPass * self.stepDown))

    @classmethod
    def FromTool(cls, tool, zStart, zFinal, zStepDown=0):
        rMax = float(tool.Diameter) / 2.0
        rMin = float(tool.TipDiameter) / 2.0
        toolangle = math.tan(math.radians(tool.CuttingEdgeAngle.Value / 2.0))
        zScale = 1.0 / toolangle
        zStop = zStart - rMax * zScale
        zOff = rMin * zScale

        return _Geometry(zStart + zOff, max(zStop + zOff, zFinal), zScale, zStepDown)

    @classmethod
    def FromObj(cls, obj, model):
        if obj.BaseShapes and hasattr(obj.BaseShapes[0], "Shape"):
            zStart = obj.BaseShapes[0].Shape.BoundBox.ZMax
        elif obj.Base and obj.Base[0][0] and hasattr(obj.Base[0][0], "Shape"):
            if len(obj.Base[0]) > 1 and "Face" in obj.Base[0][1][0]:
                faceName = obj.Base[0][1][0]
                faceIndex = int(faceName.replace("Face", "")) - 1
                face = obj.Base[0][0].Shape.Faces[faceIndex]
                zStart = face.BoundBox.ZMax
            else:
                zStart = obj.Base[0][0].Shape.BoundBox.ZMax
        else:
            zStart = model.Shape.BoundBox.ZMax
            Path.Log.error("Base object not set")
        finalDepth = obj.FinalDepth.Value
        stepDown = abs(obj.StepDown.Value)

        return cls.FromTool(obj.ToolController.Tool, zStart, finalDepth, stepDown)


def _calculate_depth(MIC, geom):
    # given a maximum inscribed circle (MIC) and tool angle,
    # return depth of cut relative to zStart.
    depth = geom.start - round(MIC * geom.scale, 4)

    return max(depth, geom.maximumDepth) + geom.offset


def _get_maximumUsableDepth(wires, geom):
    """
    Calculate maximum engraving depth for a list of wires
    belonging to one face.
    """

    def _get_depth(MIC, geom):
        """Similar logic to _calculate_depth but without stepdown and offset calculations"""
        depth = geom.start - round(MIC * geom.scale, 4)
        return max(depth, geom.stop)

    min_depth = None

    for wire in wires:
        for edge in wire:
            dist = edge.getDistances()
            depth = min(_get_depth(dist[0], geom), _get_depth(dist[1], geom))

            if min_depth is None:
                min_depth = depth
            else:
                min_depth = min(min_depth, depth)

    return min_depth


def _getPartEdge(edge, geom):
    dist = edge.getDistances()
    zBegin = _calculate_depth(dist[0], geom)
    zEnd = _calculate_depth(dist[1], geom)
    return edge.toShape(zBegin, zEnd)


def _getPartEdges(obj, vWire, geom):
    edges = []
    for e in vWire:
        edges.append(_getPartEdge(e, geom))
    return edges


class ObjectVcarve(PathEngraveBase.ObjectOp):
    """Proxy class for Vcarve operation."""

    def opFeatures(self, obj):
        """opFeatures(obj) ... return all standard features and edges based geometries"""
        return (
            PathOp.FeatureTool
            | PathOp.FeatureHeights
            | PathOp.FeatureDepths
            | PathOp.FeatureStepDown
            | PathOp.FeatureBaseFaces
            | PathOp.FeatureCoolant
        )

    def setupAdditionalProperties(self, obj):
        if not hasattr(obj, "BaseShapes"):
            obj.addProperty(
                "App::PropertyLinkList",
                "BaseShapes",
                "Path",
                QT_TRANSLATE_NOOP("App::Property", "Additional base objects to be engraved"),
            )
        obj.setEditorMode("BaseShapes", 2)  # hide

        if not hasattr(obj, "OptimizeMovements"):

            obj.addProperty(
                "App::PropertyBool",
                "OptimizeMovements",
                "Path",
                QT_TRANSLATE_NOOP("App::Property", "Optimize movements"),
            )
            obj.OptimizeMovements = False

        if not hasattr(obj, "FinishingPass"):
            obj.addProperty(
                "App::PropertyBool",
                "FinishingPass",
                "Path",
                QT_TRANSLATE_NOOP("App::Property", "Add finishing pass"),
            )
            obj.FinishingPass = False

        if not hasattr(obj, "FinishingPassZOffset"):
            obj.addProperty(
                "App::PropertyDistance",
                "FinishingPassZOffset",
                "Path",
                QT_TRANSLATE_NOOP("App::Property", "Finishing pass Z offset"),
            )

            obj.FinishingPassZOffset = "0.00"

    def initOperation(self, obj):
        """initOperation(obj) ... create vcarve specific properties."""
        obj.addProperty(
            "App::PropertyFloat",
            "Discretize",
            "Path",
            QT_TRANSLATE_NOOP("App::Property", "The deflection value for discretizing arcs"),
        )
        obj.addProperty(
            "App::PropertyFloat",
            "Colinear",
            "Path",
            QT_TRANSLATE_NOOP(
                "App::Property",
                "Cutoff for removing colinear segments (degrees). \
                        default=10.0.",
            ),
        )
        obj.addProperty(
            "App::PropertyFloat",
            "Tolerance",
            "Path",
            QT_TRANSLATE_NOOP("App::Property", "Vcarve Tolerance"),
        )

        obj.Colinear = 10.0
        obj.Discretize = 0.25
        obj.Tolerance = Path.Preferences.defaultGeometryTolerance()
        # keep copy in local object to use in methods which do not operate directly on obj
        # we use getattr because OpsDefaultEditor may trigger this method to gather list of
        # default operation settings but reading from OpPrototype object fails
        self.Tolerance = getattr(obj, "Tolerance", Path.Preferences.defaultGeometryTolerance())
        self.setupAdditionalProperties(obj)

    def opOnDocumentRestored(self, obj):
        # upgrade ...
        self.setupAdditionalProperties(obj)

    def buildMedialWires(self, obj, faces):
        """
        constructs a medial axis path using openvoronoi
        :returns: dictionary - each face object is a key containing list of wires"""

        medial_wires_by_face = dict()
        edges_by_face = dict()  # non processed voronoi edges, for debugging

        self.voronoiDebugMedialCache = dict()
        self.voronoiDebugEdgeCache = dict()

        def is_exterior(vertex, face):
            vector = FreeCAD.Vector(vertex.toPoint(face.BoundBox.ZMin))
            (u, v) = face.Surface.parameter(vector)
            # isPartOfDomain is faster than face.IsInside(...)
            return not face.isPartOfDomain(u, v)

        def insert_many_wires(vd, wires):
            for wire in wires:
                Path.Log.debug("discretize value: {}".format(obj.Discretize))
                pts = wire.discretize(QuasiDeflection=obj.Discretize)
                ptv = [FreeCAD.Vector(p.x, p.y) for p in pts]
                # Check over the last point before just closing the polygon
                # by adding the start again.  If the discretizer was aiming
                # for the last point and missed by a little bit, closing the
                # polygon as is could result in OpenVoronoi truncating the
                # coordinates to a self-intersecting polygon which is invalid.
                # Instead, if the last point is close to the first, remove it
                # and let the final append close the polygon.
                # See issue 8064
                if len(ptv) > 0:
                    dist = ptv[-1].distanceToPoint(ptv[0])
                    if dist < FreeCAD.Base.Precision.confusion():
                        Path.Log.debug(
                            "Removing bad carve point: {} from polygon origin".format(dist)
                        )
                        del ptv[-1]
                ptv.append(ptv[0])

                for i in range(len(ptv) - 1):
                    vd.addSegment(ptv[i], ptv[i + 1])

        for f in faces:
            voronoiWires = []
            vd = Path.Voronoi.Diagram()
            insert_many_wires(vd, f.Wires)

            vd.construct()
            edges_by_face[f] = vd.Edges

            for e in vd.Edges:
                if e.isPrimary():
                    if e.isBorderline():
                        e.Color = BORDERLINE
                    else:
                        e.Color = PRIMARY
                else:
                    e.Color = SECONDARY

            # filter our colinear edged so there are fewer ones
            # to iterate over in colorExterior which is slow
            vd.colorColinear(COLINEAR, obj.Colinear)

            vd.colorExterior(EXTERIOR1)
            vd.colorExterior(EXTERIOR2, lambda v: is_exterior(v, f))

            # if colorTwin is done before colorExterior we seem to have
            # much more weird exterior edges needed to be filtered out,
            # keep it here to be safe
            vd.colorTwins(TWIN)

            wires = _collectVoronoiWires(vd)
            wires = _sortVoronoiWires(wires)
            voronoiWires.extend(wires)

            medial_wires_by_face[f] = voronoiWires

        self.voronoiDebugMedialCache = medial_wires_by_face
        self.voronoiDebugEdgeCache = edges_by_face

        return medial_wires_by_face

    def buildCommandList(self, obj, faces):
        """
        Build command list to cut wires - based on voronoi
        wire list from buildMedialWires
        """

        def getPositionHistory(wire):
            """
            Get CNC current and previous head position assuming it reached the end of the wire
            returns: previousPosition, currentPostion tuple
            """

            if not wire:
                return None

            lastEdge = wire[-1]
            return (
                lastEdge.valueAt(lastEdge.FirstParameter),
                lastEdge.valueAt(lastEdge.LastParameter),
            )

        def cutWires(wires, pathlist, optimizeMovements=False):

            positionHistory = None

            for w in wires:
                pWire = _getPartEdges(obj, w, geom)
                if pWire:
                    pathlist.extend(_cutWire(pWire, positionHistory))

                    # movement optimization only works if we provide head position history
                    if optimizeMovements:
                        positionHistory = getPositionHistory(pWire)

        def _cutWire(wire, positionHistory=None):
            path = []

            backtrack_edges = []

            # we start vcarving another wire which may not be connected to previous one
            # but using some routing logic we may avoid raising CNC toolbit and using G0
            # and instead traverse back already carved edges at full speed

            backtrack_edges = generateVirtualBackTrackEdges(positionHistory, wire[0], obj.Tolerance)

            edge_list = backtrack_edges + wire

            e = edge_list[0]
            newPosition = e.valueAt(e.FirstParameter)

            hSpeed = obj.ToolController.HorizFeed.Value
            vSpeed = obj.ToolController.VertFeed.Value

            # check if we can smart-skip using G0 repositioning which is slow
            if not canSkipRepositioning(positionHistory, newPosition, obj.Tolerance):
                path.append(Path.Command("G0", {"Z": obj.SafeHeight.Value}))
                path.append(
                    Path.Command(
                        "G0",
                        {
                            "X": newPosition.x,
                            "Y": newPosition.y,
                            "Z": obj.SafeHeight.Value,
                        },
                    )
                )

                path.append(
                    Path.Command(
                        "G1",
                        {
                            "X": newPosition.x,
                            "Y": newPosition.y,
                            "Z": newPosition.z,
                            "F": vSpeed,
                        },
                    )
                )
            else:  # skip repositioning
                # technically hSpeed + vSpeed should be properly recalculated into F parameter
                # as cmdsForEdge does but we either cut max 0.5 mm through stock or backtrack
                # over already carved edges, so hSpeed will be just fine
                path.append(
                    Path.Command(
                        "G1 X{} Y{} Z{} F{}".format(
                            newPosition.x, newPosition.y, newPosition.z, hSpeed
                        )
                    )
                )

            for e in edge_list:
                path.extend(Path.Geom.cmdsForEdge(e, hSpeed=hSpeed, vSpeed=vSpeed))

            return path

        pathlist = []
        pathlist.append(Path.Command("(starting)"))

        geom = _Geometry.FromObj(obj, self.model[0])

        # iterate over each face separately
        for face, wires in self.buildMedialWires(obj, faces).items():

            # If using depth step-down, calculate maximum usable depth for current face.
            # This is done to avoid adding additional step-down engraving passes when it
            # would make no sense as depth is limited by Maximum Inscribed Circle anyway.

            maximumUsableDepth = geom.stop

            if geom.stepDown > 0:
                _maximumUsableDepth = _get_maximumUsableDepth(wires, geom)
                if _maximumUsableDepth is not None:
                    maximumUsableDepth = _maximumUsableDepth
                    Path.Log.debug(f"Maximum usable depth for current face: {maximumUsableDepth}")

            # first pass
            cutWires(wires, pathlist, obj.OptimizeMovements)

            # subsequent stepDown depth passes (if any)
            while geom.incrementStepDownDepth(maximumUsableDepth):
                cutWires(wires, pathlist, obj.OptimizeMovements)

            # add finishing pass if enabled

            if obj.FinishingPass:
                geom.offset = obj.FinishingPassZOffset.Value

                cutWires(wires, pathlist, obj.OptimizeMovements)

        self.commandlist = pathlist

    def opExecute(self, obj):
        """opExecute(obj) ... process engraving operation"""
        Path.Log.track()

        self.voronoiDebugMedialCache = None
        self.voronoiDebugEdgesCache = None

        if obj.ToolController is None:
            return

        if not hasattr(obj.ToolController.Tool, "CuttingEdgeAngle"):
            Path.Log.info(
                translate(
                    "CAM_Vcarve",
                    "VCarve requires an engraving cutter with a cutting edge angle",
                )
            )
            return

        if obj.ToolController.Tool.CuttingEdgeAngle >= 180.0:
            Path.Log.info(
                translate("CAM_Vcarve", "Engraver cutting edge angle must be < 180 degrees.")
            )
            return

        try:
            faces = []

            for base in obj.BaseShapes:
                faces.extend(base.Shape.Faces)

            for base in obj.Base:
                for sub in base[1]:
                    shape = getattr(base[0].Shape, sub)
                    if isinstance(shape, Part.Face):
                        faces.append(shape)

            if not faces:
                for model in self.model:
                    if model.isDerivedFrom("Sketcher::SketchObject") or model.isDerivedFrom(
                        "Part::Part2DObject"
                    ):
                        faces.extend(model.Shape.Faces)

            if faces:
                self.buildCommandList(obj, faces)
            else:
                Path.Log.error(
                    translate(
                        "PathVcarve",
                        "The Job Base Object has no engraveable element. Engraving operation will produce no output.",
                    )
                )

        except Exception:
            Path.Log.warning(
                "Error processing Base object. Engraving operation will produce no output."
            )
            import traceback

            Path.Log.error(f"Engraving operation exception: {traceback.format_exc()}")

    def opUpdateDepths(self, obj, ignoreErrors=False):
        """updateDepths(obj) ... engraving is always done at the top most z-value"""
        job = PathUtils.findParentJob(obj)
        self.opSetDefaultValues(obj, job)

    def opSetDefaultValues(self, obj, job):
        """opSetDefaultValues(obj) ... set depths for vcarving"""
        if PathOp.FeatureDepths & self.opFeatures(obj):
            if job and len(job.Model.Group) > 0:
                bb = job.Proxy.modelBoundBox(job)
                obj.OpStartDepth = bb.ZMax
                obj.OpFinalDepth = job.Stock.Shape.BoundBox.ZMin
            else:
                obj.OpFinalDepth = -0.1

    def isToolSupported(self, obj, tool):
        """isToolSupported(obj, tool) ... returns True if v-carve op can work with tool."""
        return (
            hasattr(tool, "Diameter")
            and hasattr(tool, "CuttingEdgeAngle")
            and hasattr(tool, "TipDiameter")
        )

    def debugVoronoiMedial(self, obj):
        """Debug function to display calculated voronoi medial wires"""

        if not getattr(self, "voronoiDebugMedialCache", None):
            Path.Log.error("debugVoronoi: empty debug cache. Recompute VCarve operation first")
            return

        vPart = FreeCAD.activeDocument().addObject("App::Part", f"{obj.Name}-VoronoiDebugMedial")

        wiresToShow = []

        for face, wires in self.voronoiDebugMedialCache.items():
            for wire in wires:
                currentPartWire = Part.Wire()
                currentPartWire.fixTolerance(0.01)
                for edge in wire:
                    currentEdge = edge.toShape()

                    for v in currentEdge.Vertexes:
                        v.fixTolerance(0.1)

                    currentPartWire.add(currentEdge)
                wiresToShow.append(currentPartWire)

        for w in wiresToShow:
            vPart.addObject(Part.show(w))

    def debugVoronoiEdges(self, obj):
        """Debug function to display calculated voronoi edges"""

        if not getattr(self, "voronoiDebugEdgeCache", None):
            Path.Log.error("debugVoronoi: empty debug cache. Recompute VCarve operation first")
            return

        vPart = FreeCAD.activeDocument().addObject("App::Part", f"{obj.Name}-VoronoiDebugEdge")

        edgesToShow = []

        for face, edges in self.voronoiDebugEdgeCache.items():
            for edge in edges:  # those are voronoi Edge objects, not FC Edge
                currentEdge = edge.toShape()

                edgesToShow.append(currentEdge)

        for e in edgesToShow:
            vPart.addObject(Part.show(e))


def SetupProperties():
    return ["Discretize"]


def Create(name, obj=None, parentJob=None):
    """Create(name) ... Creates and returns a Vcarve operation."""
    if obj is None:
        obj = FreeCAD.ActiveDocument.addObject("Path::FeaturePython", name)
    obj.Proxy = ObjectVcarve(obj, name, parentJob)
    return obj