commit ccd48612c7f6a5c06c9193a548c6076e2779b177
Author: Roger Maitland <gumyr9@gmail.com>
Date:   Fri Jul 1 11:27:14 2022 -0400

    Initial prototype

diff --git a/cq3.py b/cq3.py
new file mode 100644
index 0000000..3e99f9d
--- /dev/null
+++ b/cq3.py
@@ -0,0 +1,741 @@
+import builtins
+from math import pi, sin
+from typing import Union, Iterable, Sequence, Callable
+from enum import Enum, auto
+import cadquery as cq
+from cadquery.hull import find_hull
+from cadquery import (
+    Edge,
+    Face,
+    Wire,
+    Vector,
+    Shape,
+    Location,
+    Vertex,
+    Compound,
+    Solid,
+    Plane,
+)
+from cadquery.occ_impl.shapes import VectorLike, Real
+import cq_warehouse.extensions
+
+z_axis = (Vector(0, 0, 0), Vector(0, 0, 1))
+
+
+def __matmul__custom(e: Union[Edge, Wire], p: float):
+    return e.positionAt(p)
+
+
+def __mod__custom(e: Union[Edge, Wire], p: float):
+    return e.tangentAt(p)
+
+
+Edge.__matmul__ = __matmul__custom
+Edge.__mod__ = __mod__custom
+line = Edge.makeLine(Vector(0, 0, 0), Vector(10, 0, 0))
+# print(f"position of line at 1/2: {line @ 0.5=}")
+# print(f"tangent of line at 1/2: {line % 0.5=}")
+
+
+def by_x(obj: Shape) -> float:
+    return obj.Center().x
+
+
+def _by_x_shape(self) -> float:
+    return self.Center().x
+
+
+Shape.by_x = _by_x_shape
+
+
+def by_y(obj: Shape) -> float:
+    return obj.Center().y
+
+
+def _by_y_shape(self) -> float:
+    return self.Center().y
+
+
+Shape.by_y = _by_y_shape
+
+
+def by_z(obj: Shape) -> float:
+    return obj.Center().z
+
+
+def _by_z_shape(self) -> float:
+    return self.Center().z
+
+
+Shape.by_z = _by_z_shape
+
+
+def by_length(obj: Union[Edge, Wire]) -> float:
+    return obj.Length()
+
+
+def _by_length_edge_or_wire(self) -> float:
+    return self.Length()
+
+
+Edge.by_length = _by_length_edge_or_wire
+Wire.by_length = _by_length_edge_or_wire
+
+
+def by_radius(obj: Union[Edge, Wire]) -> float:
+    return obj.radius()
+
+
+def _by_radius_edge_or_wire(self) -> float:
+    return self.radius()
+
+
+Edge.by_radius = _by_radius_edge_or_wire
+Wire.by_radius = _by_radius_edge_or_wire
+
+
+def by_area(obj: cq.Shape) -> float:
+    return obj.Area()
+
+
+def _by_area_shape(self) -> float:
+    return self.Area()
+
+
+Shape.by_area = _by_area_shape
+
+
+class SortBy(Enum):
+    NONE = auto()
+    X = auto()
+    Y = auto()
+    Z = auto()
+    LENGTH = auto()
+    RADIUS = auto()
+    AREA = auto()
+    VOLUME = auto()
+    DISTANCE = auto()
+
+
+class Mode(Enum):
+    """Combination Mode"""
+
+    ADDITION = auto()
+    SUBTRACTION = auto()
+    INTERSECTION = auto()
+    CONSTRUCTION = auto()
+
+
+class BuildAssembly:
+    def add(self):
+        pass
+
+
+def _null(self):
+    return self
+
+
+Solid.null = _null
+Compound.null = _null
+
+
+class Until(Enum):
+    NEXT = auto()
+    LAST = auto()
+
+
+class CqObject(Enum):
+    EDGE = auto()
+    FACE = auto()
+    VERTEX = auto()
+
+
+class Build3D:
+    @property
+    def workplane_count(self) -> int:
+        return len(self.workplanes)
+
+    @property
+    def pending_face_count(self) -> int:
+        return len(self.pending_faces)
+
+    def __init__(
+        self,
+        parent: BuildAssembly = None,
+        mode: Mode = Mode.ADDITION,
+        workplane: Plane = Plane.named("XY"),
+    ):
+        self.parent = parent
+        self.working_solid: Solid = None
+        self.workplanes: list[Plane] = [workplane]
+        self.pending_faces: dict[int : list[Face]] = {0: []}
+        self.pending_edges: dict[int : list[Edge]] = {0: []}
+        self.locations: dict[int : list[Location]] = {0: []}
+        self.last_operation: dict[CqObject : list[Shape]] = {}
+        # self.last_operation_edges: list[Edge] = []
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exception_type, exception_value, traceback):
+        pass
+
+    def push_locations(self, *pts: Union[VectorLike, Location]):
+        new_locations = [
+            Location(Vector(pt)) if not isinstance(pt, Location) else pt for pt in pts
+        ]
+        for i in range(len(self.workplanes)):
+            self.locations[i].extend(new_locations)
+        print(f"{len(self.locations[i])=}")
+        return new_locations[0] if len(new_locations) == 1 else new_locations
+
+    def add(self, obj: Union[Edge, Face], mode: Mode = Mode.ADDITION):
+        print(f"Add before: {self.locations=}")
+        print(f"Add before: {self.pending_faces=}")
+        for i, workplane in enumerate(self.workplanes):
+            if not self.locations:
+                self.locations[i] = Location(Vector())
+            for loc in self.locations[i]:
+                # located_loc = workplane.fromLocalCoords(loc)
+                print(f"{loc=}")
+                localized_location = loc * Location(workplane)
+                print(f"{localized_location=}")
+                # if i in self.workplanes:
+                if isinstance(obj, Face):
+                    self.pending_faces[i].append(
+                        # workplane.fromLocalCoords(obj.located(localized_location))
+                        obj.located(localized_location)
+                    )
+                else:
+                    self.pending_edges[i].append(
+                        # workplane.fromLocalCoords(obj.located(localized_location))
+                        obj.located(localized_location)
+                    )
+                # else:
+                #     if isinstance(obj, Face):
+                #         self.pending_faces[i] = [
+                #             # workplane.fromLocalCoords(obj.located(localized_location))
+                #             obj.located(localized_location)
+                #         ]
+                #     else:
+                #         self.pending_edges[i] = [
+                #             # workplane.fromLocalCoords(obj.located(localized_location))
+                #             obj.located(localized_location)
+                #         ]
+        print(f"Add after: {self.pending_faces=}")
+
+    def workplane(self, workplane: Plane = Plane.named("XY"), replace=True):
+        if replace:
+            self.workplanes = [workplane]
+        else:
+            self.workplanes.append(workplane)
+            self.locations[len(self.workplanes) - 1] = [Location()]
+        return workplane
+
+    def faces_to_workplanes(self, *faces: Sequence[Face], replace=False):
+        new_planes = []
+        for face in faces:
+            new_plane = Plane(origin=face.Center(), normal=face.normalAt(face.Center()))
+            new_planes.append(new_plane)
+            self.workplane(new_plane, replace)
+        return new_planes[0] if len(new_planes) == 1 else new_planes
+
+    def edges(self, sort_by: SortBy = SortBy.NONE, reverse: bool = False) -> list[Edge]:
+        if sort_by == SortBy.NONE:
+            edges = self.working_solid.Edges()
+        elif sort_by == SortBy.X:
+            edges = sorted(
+                self.working_solid.Edges(),
+                key=lambda obj: obj.Center().x,
+                reverse=reverse,
+            )
+        elif sort_by == SortBy.Y:
+            edges = sorted(
+                self.working_solid.Edges(),
+                key=lambda obj: obj.Center().y,
+                reverse=reverse,
+            )
+        elif sort_by == SortBy.Z:
+            edges = sorted(
+                self.working_solid.Edges(),
+                key=lambda obj: obj.Center().z,
+                reverse=reverse,
+            )
+        elif sort_by == SortBy.LENGTH:
+            edges = sorted(
+                self.working_solid.Edges(),
+                key=lambda obj: obj.Length(),
+                reverse=reverse,
+            )
+        elif sort_by == SortBy.RADIUS:
+            edges = sorted(
+                self.working_solid.Edges(),
+                key=lambda obj: obj.radius(),
+                reverse=reverse,
+            )
+        elif sort_by == SortBy.DISTANCE:
+            edges = sorted(
+                self.working_solid.Edges(),
+                key=lambda obj: obj.Center().Length,
+                reverse=reverse,
+            )
+        else:
+            raise ValueError(f"Unable to sort edges by {sort_by}")
+
+        return edges
+
+    def faces(self, sort_by: SortBy = SortBy.NONE, reverse: bool = False) -> list[Face]:
+        if sort_by == SortBy.NONE:
+            faces = self.working_solid.Faces()
+        elif sort_by == SortBy.X:
+            faces = sorted(
+                self.working_solid.Faces(),
+                key=lambda obj: obj.Center().x,
+                reverse=reverse,
+            )
+        elif sort_by == SortBy.Y:
+            faces = sorted(
+                self.working_solid.Faces(),
+                key=lambda obj: obj.Center().y,
+                reverse=reverse,
+            )
+        elif sort_by == SortBy.Z:
+            faces = sorted(
+                self.working_solid.Faces(),
+                key=lambda obj: obj.Center().z,
+                reverse=reverse,
+            )
+        elif sort_by == SortBy.AREA:
+            faces = sorted(
+                self.working_solid.Faces(), key=lambda obj: obj.Area(), reverse=reverse
+            )
+        elif sort_by == SortBy.DISTANCE:
+            faces = sorted(
+                self.working_solid.Faces(),
+                key=lambda obj: obj.Center().Length,
+                reverse=reverse,
+            )
+        else:
+            raise ValueError(f"Unable to sort edges by {sort_by}")
+        return faces
+
+    def vertices(
+        self, sort_by: SortBy = SortBy.NONE, reverse: bool = False
+    ) -> list[Vertex]:
+        if sort_by == SortBy.NONE:
+            vertices = self.working_solid.Vertices()
+        elif sort_by == SortBy.X:
+            vertices = sorted(
+                self.working_solid.Vertices(),
+                key=lambda obj: obj.Center().x,
+                reverse=reverse,
+            )
+        elif sort_by == SortBy.Y:
+            vertices = sorted(
+                self.working_solid.Vertices(),
+                key=lambda obj: obj.Center().y,
+                reverse=reverse,
+            )
+        elif sort_by == SortBy.Z:
+            vertices = sorted(
+                self.working_solid.Vertices(),
+                key=lambda obj: obj.Center().z,
+                reverse=reverse,
+            )
+        elif sort_by == SortBy.DISTANCE:
+            vertices = sorted(
+                self.working_solid.Vertices(),
+                key=lambda obj: obj.Center().Length,
+                reverse=reverse,
+            )
+        else:
+            raise ValueError(f"Unable to sort edges by {sort_by}")
+        return vertices
+
+    def place_solids(
+        self,
+        new_solids: list[Solid, Compound],
+        mode: Mode = Mode.ADDITION,
+        clean: bool = True,
+    ):
+
+        Solid.clean_op = Solid.clean if clean else Solid.null
+        Compound.clean_op = Compound.clean if clean else Compound.null
+
+        before_vertices = (
+            set() if self.working_solid is None else set(self.working_solid.Vertices())
+        )
+        before_edges = (
+            set() if self.working_solid is None else set(self.working_solid.Edges())
+        )
+        before_faces = (
+            set() if self.working_solid is None else set(self.working_solid.Faces())
+        )
+
+        if mode == Mode.ADDITION:
+            if self.working_solid is None:
+                if len(new_solids) == 1:
+                    self.working_solid = new_solids[0]
+                else:
+                    self.working_solid = new_solids.pop().fuse(*new_solids)
+            else:
+                self.working_solid = self.working_solid.fuse(*new_solids).clean_op()
+        elif mode == Mode.SUBTRACTION:
+            if self.working_solid is None:
+                raise ValueError("Nothing to subtract from")
+            self.working_solid = self.working_solid.cut(*new_solids).clean_op()
+        elif mode == Mode.INTERSECTION:
+            if self.working_solid is None:
+                raise ValueError("Nothing to intersect with")
+            self.working_solid = self.working_solid.intersect(*new_solids).clean_op()
+
+        self.last_operation[CqObject.VERTEX] = list(
+            set(self.working_solid.Vertices()) - before_vertices
+        )
+        self.last_operation[CqObject.EDGE] = list(
+            set(self.working_solid.Edges()) - before_edges
+        )
+        self.last_operation[CqObject.FACE] = list(
+            set(self.working_solid.Faces()) - before_faces
+        )
+
+    def extrude(
+        self,
+        until: Union[float, Until, Face],
+        both: bool = False,
+        taper: float = None,
+        mode: Mode = Mode.ADDITION,
+        clean: bool = True,
+    ):
+
+        new_solids: list[Solid] = []
+        for plane_index, faces in self.pending_faces.items():
+            for face in faces:
+                new_solids.append(
+                    Solid.extrudeLinear(
+                        face, self.workplanes[plane_index].zDir * until, 0
+                    )
+                )
+                if both:
+                    new_solids.append(
+                        Solid.extrudeLinear(
+                            face,
+                            self.workplanes[plane_index].zDir * until * -1.0,
+                            0,
+                        )
+                    )
+
+        self.place_solids(new_solids, mode, clean)
+
+        return new_solids[0] if len(new_solids) == 1 else new_solids
+
+    def revolve(
+        self,
+        angle_degrees: float = 360.0,
+        axis_start: VectorLike = None,
+        axis_end: VectorLike = None,
+        mode: Mode = Mode.ADDITION,
+        clean: bool = True,
+    ):
+        # Make sure we account for users specifying angles larger than 360 degrees, and
+        # for OCCT not assuming that a 0 degree revolve means a 360 degree revolve
+        angle = angle_degrees % 360.0
+        angle = 360.0 if angle == 0 else angle
+
+        new_solids = []
+        for i, workplane in enumerate(self.workplanes):
+            axis = []
+            if axis_start is None:
+                axis.append(workplane.fromLocalCoords(Vector(0, 0, 0)))
+            else:
+                axis.append(workplane.fromLocalCoords(Vector(axis_start)))
+
+            if axis_end is None:
+                axis.append(workplane.fromLocalCoords(Vector(0, 1, 0)))
+            else:
+                axis.append(workplane.fromLocalCoords(Vector(axis_end)))
+            print(f"Revolve: {axis=}")
+
+            for face in self.pending_faces[i]:
+                print(f"{type(face)=}")
+                print(f"{face.Area()=}")
+                print(f"{face.Center()=}")
+                print(f"{face.normalAt(face.Center())=}")
+                new_solids.append(Solid.revolve(face, angle, *axis))
+
+        self.place_solids(new_solids, mode, clean)
+
+        return new_solids[0] if len(new_solids) == 1 else new_solids
+
+    def loft(self, ruled: bool = False, mode: Mode = Mode.ADDITION, clean: bool = True):
+
+        new_solids = []
+        for i in range(len(self.workplanes)):
+            new_wires = []
+            for face in self.faces[i]:
+                new_wires.append(face.outerWire())
+            print(f"{len(new_wires)=}")
+            new_solids.append(Solid.makeLoft(new_wires, ruled))
+
+        self.place_solids(new_solids, mode, clean)
+
+        return new_solids[0] if len(new_solids) == 1 else new_solids
+
+    def fillet(self, *edges: Sequence[Edge], radius: float):
+        self.working_solid = self.working_solid.fillet(radius, [e for e in edges])
+
+
+class Build2D:
+    def __init__(self, parent: Build3D = None, mode: Mode = Mode.ADDITION):
+        self.working_surface = Compound.makeCompound(())
+        self.pending_edges: list[Edge] = []
+        # self.tags: dict[str, Face] = {}
+        self.parent = parent
+        self.locations: list[Location] = []
+        self.mode = mode
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exception_type, exception_value, traceback):
+        print(f"Exit: Area of generated Face: {self.working_surface.Area()}")
+        if self.parent is not None:
+            self.parent.add(self.working_surface, self.mode)
+
+    def add(self, f: Face, mode: Mode = Mode.ADDITION):
+        new_faces = self.place_face(f, mode)
+        return new_faces if len(new_faces) > 1 else new_faces[0]
+
+    def push_locations(self, *pts: Sequence[Union[VectorLike, Location]]):
+        new_locations = [
+            Location(Vector(pt)) if not isinstance(pt, Location) else pt for pt in pts
+        ]
+        self.locations.extend(new_locations)
+        return new_locations
+
+    def assemble_edges(self, mode: Mode = Mode.ADDITION, tag: str = None) -> Face:
+        pending_face = Face.makeFromWires(Wire.assembleEdges(self.pending_edges))
+        self.add(pending_face, mode, tag)
+        self.pending_edges = []
+        # print(f"Area of generated Face: {pending_face.Area()}")
+        return pending_face
+
+    def hull_edges(self, mode: Mode = Mode.ADDITION, tag: str = None) -> Face:
+        pending_face = find_hull(self.pending_edges)
+        self.add(pending_face, mode, tag)
+        self.pending_edges = []
+        # print(f"Area of generated Face: {pending_face.Area()}")
+        return pending_face
+
+    def rect(
+        self,
+        width: float,
+        height: float,
+        angle: float = 0,
+        mode: Mode = Mode.ADDITION,
+    ) -> Face:
+        """
+        Construct a rectangular face.
+        """
+
+        new_faces = self.place_face(
+            Face.makePlane(height, width).rotate(*z_axis, angle), mode
+        )
+
+        return new_faces if len(new_faces) > 1 else new_faces[0]
+
+    def circle(self, radius: float, mode: Mode = Mode.ADDITION) -> Face:
+        """
+        Construct a circular face.
+        """
+
+        new_faces = self.place_face(
+            Face.makeFromWires(Wire.makeCircle(radius, *z_axis)), mode
+        )
+
+        return new_faces if len(new_faces) > 1 else new_faces[0]
+
+    def place_face(self, face: Face, mode: Mode = Mode.ADDITION):
+
+        if not self.locations:
+            self.locations = [Location(Vector())]
+        new_faces = [face.located(location) for location in self.locations]
+
+        if mode == Mode.ADDITION:
+            self.working_surface = self.working_surface.fuse(*new_faces).clean()
+        elif mode == Mode.SUBTRACTION:
+            self.working_surface = self.working_surface.cut(*new_faces).clean()
+        elif mode == Mode.INTERSECTION:
+            self.working_surface = self.working_surface.intersect(*new_faces).clean()
+        elif mode == Mode.CONSTRUCTION:
+            pass
+        else:
+            raise ValueError(f"Invalid mode: {mode}")
+
+        self.locations = []
+        return new_faces
+
+
+class Build1D:
+    def __init__(self, parent: Build2D = None, mode: Mode = Mode.ADDITION):
+        self.edge_list = []
+        self.tags: dict[str, Edge] = {}
+        self.parent = parent
+        self.mode = mode
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exception_type, exception_value, traceback):
+        pending_face = Face.makeFromWires(Wire.assembleEdges(self.edge_list))
+        print(f"Exit: Area of generated Face: {pending_face.Area()}")
+        # print(self.tags)
+        self.parent.add(pending_face, self.mode)
+
+    def edges(self) -> list[Edge]:
+        return self.edge_list
+
+    def vertices(self) -> list[Vertex]:
+        vertex_list = []
+        for e in self.edge_list:
+            vertex_list.extend(e.Vertices())
+        return list(set(vertex_list))
+
+    def polyline(
+        self,
+        *pts: VectorLike,
+        mode: Mode = Mode.ADDITION,
+        tag: str = None,
+    ):
+        if len(pts) < 2:
+            raise ValueError("polyline requires two or more pts")
+
+        lines_pts = [Vector(p) for p in pts]
+
+        new_edges = [
+            Edge.makeLine(lines_pts[i], lines_pts[i + 1])
+            for i in range(len(lines_pts) - 1)
+        ]
+
+        for e in new_edges:
+            e.forConstruction = mode == Mode.CONSTRUCTION
+        self.edge_list.extend(new_edges)
+
+        return_value = (
+            new_edges[0] if len(new_edges) == 1 else Wire.assembleEdges(new_edges)
+        )
+
+        if tag:
+            if len(new_edges) > 1:
+                for i, edge in enumerate(new_edges):
+                    self.tags[f"{tag}-{i}"] = edge
+            else:
+                self.tags[tag] = new_edges[0]
+
+        return return_value
+
+
+# with Build2D() as f:
+#     # Start with a central circle with a square quarter
+#     c6 = f.circle(6)
+#     print(f"{type(c6)=}, {c6.Center()=}")
+#     f.push((3, 3))
+#     r6 = f.rect(6, 6)
+#     print(f"{type(r6)=}, {r6.Center()=}")
+#     # Create some locations for the cutouts
+#     polar_locations = [
+#         Location(Vector(3, 0, 0).rotateZ(a), Vector(0, 0, 1), a)
+#         for a in range(0, 360, 45)
+#     ]
+#     f.push(*polar_locations)
+#     # Cutout a set of diamonds
+#     with Build1D(parent=f, mode=Mode.SUBTRACTION) as e:
+#         # Instantiate a simple line
+#         l = e.polyline((0, 0), (1, 1))
+#         print(f"Type of line: {type(l)}")
+#         # Instantiate a polyline
+#         m = e.polyline(l.endPoint(), (2, 0), (1, -1))
+#         print(f"Type of polyline: {type(m)}")
+#         # Create another line but don't assign a global to it
+#         e.polyline(m.endPoint(), l.startPoint())
+#         # Extract all of the vertices - two for each Edge
+#         all_vertices = e.vertices()
+#         print(f"Type of vertices: {type(all_vertices)}")
+#         print(f"Total number of vertices: {len(all_vertices)}")
+#         # Sort these vertices by Y value
+#         corners_sorted_by_Y = sorted(all_vertices, key=lambda v: v.Y)
+#         # Filter the sorted value to extract just those on the X axis
+#         side_corners = list(filter(lambda v: abs(v.Y) < 1e-5, corners_sorted_by_Y))
+#         print(f"Number of vertices after filter: {len(side_corners)}")
+#         print("Corner vertices at X axis:")
+#         for v in side_corners:
+#             print(v.toTuple())
+
+# with Build2D() as f2:
+#     with Build1D(parent=f2) as c2:
+#         pts = [Vector(10, 0, 0).rotateZ(a) for a in range(0, 360, 60)]
+#         c2.polyline(*pts)
+# print(f"{type(c2.face)=}")
+
+# with Build3D() as s1:
+#     with Build2D(s1) as f1:
+#         f1.rect(10, 10)
+#     box = s1.extrude(10)
+#     s1.faces_to_workplanes(*box.Faces())
+#     with Build2D(s1) as f2:
+#         f2.circle(3)
+#     s1.extrude(-1, mode=Mode.SUBTRACTION)
+#     # edges_by_z = sorted(s1.edges(), key=by_z, reverse=True)[0:1]
+#     # edges_by_z = s1.edges(sort_by=SortBy.Z, reverse=True)[0:1]
+#     edges_by_z = s1.edges(SortBy.Z, reverse=True)[0:1]
+#     # print(f"{edges_by_z}")
+#     # top_circle = sorted(s1.last_operation_edges, key=by_z, reverse=True)[0]
+#     # top_circle = filter(lambda f: abs(f.by_z() - 5) < 1e-5, s1.last_operation_edges)
+#     # s1.fillet(*s1.last_operation[CqObject.EDGE], radius=0.2)
+#     s1.fillet(*edges_by_z, radius=0.2)
+
+# print(s1.solid.Volume())
+
+# with Build2D() as f1:
+#     f1.push_locations((-5, -5), (-5, 5), (5, 5), (5, -5))
+#     # f1.rect(1, 1)
+#     f1.circle(1)
+# faces = [f for list in s1.faces.values() for f in list]
+
+# with Build3D() as s2:
+#     with Build2D(s2) as f1:
+#         f1.push_locations((4, 3))
+#         rect = f1.rect(6, 6)
+#     revolve = s2.pending_faces
+#     s2.revolve()
+
+with Build3D() as s2:
+    # s2.push_locations((-5, -5), (-5, 5), (5, 5), (5, -5))
+    with Build2D(s2) as f1:
+        f1.circle(1)
+
+
+# with Build3D() as s3:
+#     for i in range(21):
+#         r = 10 * sin(i * pi / 20) + 5
+#         s3.push((0, 0, i))
+#         with Build2D(s3) as f1:
+#             f1.circle(r)
+#     print(f"{len(s3.faces[0])=}")
+#     s3.loft()
+
+if "show_object" in locals():
+    show_object(s2.pending_faces[0])
+    # show_object(rect, name="rect")
+    # show_object(f1.working_surface, name="working_surface")
+    # show_object(revolve, name="revolve")
+    # show_object(f1.face_list)
+    # show_object(s1.working_solid, name="s1")
+    # show_object(s1.last_operation_edges, name="last edges")
+    # show_object(s2.solid, name="s2")
+    # show_object(f1.faces, name="f1")
+    # show_object(rface, name="rface")
+    # show_object(faces, name="circles")
+    # show_object(bumps, name="bumps")
+    # show_object(f.faces, name="f")
+    # show_object(f2.faces, name="f2")
diff --git a/rtree.py b/rtree.py
new file mode 100644
index 0000000..4916ee4
--- /dev/null
+++ b/rtree.py
@@ -0,0 +1,39 @@
+def get_bb_coords(shape: Shape) -> Tuple[float, float, float, float, float, float]:
+    bb = shape.BoundingBox()
+    return (bb.xmin, bb.ymin, bb.zmin, bb.xmax, bb.ymax, bb.zmax)
+
+
+def build_tree(shapes: Iterable[Shape]):
+    import rtree.index
+
+    p = rtree.index.Property(dimension=3)
+    t = rtree.index.RtreeContainer(properties=p)
+    for shape in shapes:
+        t.insert(shape, get_bb_coords(shape))
+    return t
+
+
+def face_outside(f: Face, ff: Face) -> bool:
+    """f exists outside of ff"""
+    # TODO: shortcut True if bbox intersection is 1d and f.Area() > 0
+    return f.cut(ff).Area() > 0
+
+
+def new_faces(self: T) -> T:
+    """Find faces not present in parent"""
+    old_faces = self.parent.findSolid().Faces()
+    old_set = set(old_faces)
+    new = [f for f in self.findSolid().Faces() if f not in old_set]
+    new_tree = build_tree(new)
+    old_tree = build_tree(
+        f for f in old_faces if any(new_tree.intersection(get_bb_coords(f)))
+    )
+    new = [
+        f
+        for f in new
+        if all(face_outside(f, ff) for ff in old_tree.intersection(get_bb_coords(f)))
+    ]
+    return self.newObject(new)
+
+
+cq.Workplane.new_faces = new_faces