Add a Hole primitive that allows easy chamfering of top and bottom edges

Author: frmdstryr

declaracad/occ/api.py

@@ -84,6 +84,7 @@
     Export,
     Face,
     HalfSpace,
+    Hole,
     Material,
     Part,
     Prism,

declaracad/occ/impl/occ_factories.py

@@ -127,6 +127,12 @@ def occ_half_space_factory():
     return OccHalfSpace
 
 
+def occ_hole():
+    from .occ_hole import OccHole
+
+    return OccHole
+
+
 def occ_hyperbola_factory():
     from .occ_hyperbola import OccHyperbola
 
@@ -414,6 +420,7 @@ def occ_export_factory():
     "Tube": occ_tube_factory,
     "Wedge": occ_wedge_factory,
     #: Primatives
+    "Hole": occ_hole,
     "HalfSpace": occ_half_space_factory,
     "Revol": occ_revol_factory,
     #: Operations

declaracad/occ/impl/occ_fillet.py

@@ -135,17 +135,17 @@ def fillet_polyline(self, child: OccPolyline) -> TopoDS_Shape:
             radius, wire = filleted_wires[i]
             topo = Topology(shape=wire)
             if last_radius is None and radius is None:
-                edges.append(topo.edges[0]) # Add common edge with no fillets
+                edges.append(topo.edges[0])  # Add common edge with no fillets
             else:
                 common = BRepAlgoAPI_Common(last_wire, wire)
                 common.Build()
                 common_edges = Topology(shape=common.Shape()).edges
                 assert common_edges, "Fillet radius too large"
                 edges.extend(common_edges)
             if i == last_index:
-                edges.extend(topo.edges[1:]) # Add all remaining edges
+                edges.extend(topo.edges[1:])  # Add all remaining edges
             elif radius is not None:
-                edges.append(topo.edges[1]) # Add only the filleted edge
+                edges.append(topo.edges[1])  # Add only the filleted edge
             last_wire = wire
             last_topo = topo
             last_radius = radius

declaracad/occ/impl/occ_hole.py

@@ -0,0 +1,94 @@
+"""
+Copyright (c) 2025, Jairus Martin.
+
+Distributed under the terms of the GPL v3 License.
+
+The full license is in the file LICENSE, distributed with this software.
+
+"""
+
+from typing import Optional
+
+from OCCT.BRepBuilderAPI import (
+    BRepBuilderAPI_MakeFace,
+    BRepBuilderAPI_MakePolygon,
+    BRepBuilderAPI_Transform,
+)
+from OCCT.BRepPrimAPI import BRepPrimAPI_MakeCylinder, BRepPrimAPI_MakeRevol
+from OCCT.gp import gp_Ax3, gp_Pnt, gp_Trsf
+
+from declaracad.occ.shape import ProxyHole
+
+from .occ_shape import AZ, DEFAULT_AXIS, OccShape, coerce_axis
+from .topology import Topology
+
+
+class OccHole(OccShape, ProxyHole):
+    reference = ""
+
+    def create_shape(self):
+        d = self.declaration
+        r = d.diameter / 2
+        h = d.depth
+        if d.top_edge.distance or d.bottom_edge.distance:
+            poly = BRepBuilderAPI_MakePolygon()
+
+            poly.Add(gp_Pnt(0, 0, 0))
+            if edge_style := d.bottom_edge:
+                d1 = abs(edge_style.distance)
+                d2 = abs(edge_style.distance2 or d1)
+                if edge_style.kind == "chamfer":
+                    d1 = -d1
+                y = r + d1
+                if y < 0:
+                    raise ValueError(
+                        f"Bottom edge chamfer distance cannot be > hole radius. Got  R={r} D={d1}"
+                    )
+                elif y > 0:
+                    poly.Add(gp_Pnt(0, y, 0))
+                # If y == 0 skip the point
+                poly.Add(gp_Pnt(0, r, d2))
+                z = d2
+            else:
+                poly.Add(gp_Pnt(0, r, 0))
+                z = 0
+
+            if edge_style := d.top_edge:
+                d1 = abs(edge_style.distance)
+                d2 = abs(edge_style.distance2 or d1)
+                if edge_style.kind == "chamfer":
+                    d1 = -d1
+                poly.Add(gp_Pnt(0, r, h - d2))
+                y = r + d1
+                if y < 0:
+                    raise ValueError(
+                        f"Top edge chamfer cannot be > hole radius. Got R={r} D={d1}"
+                    )
+                elif y > 0:
+                    poly.Add(gp_Pnt(0, y, h))
+                # If y == 0 skip the point
+            else:
+                poly.Add(gp_Pnt(0, r, h))
+            poly.Add(gp_Pnt(0, 0, h))
+            poly.Close()
+            face = BRepBuilderAPI_MakeFace(poly.Wire()).Face()
+            revol = BRepPrimAPI_MakeRevol(face, AZ, False)
+            t = self.get_transform()
+            shape = BRepBuilderAPI_Transform(revol.Shape(), t, False).Shape()
+        else:
+            cylinder = BRepPrimAPI_MakeCylinder(coerce_axis(d.axis), r, h)
+            shape = cylinder.Shape()
+
+        self.shape = shape
+
+    def set_diameter(self, diameter: float):
+        self.create_shape()
+
+    def set_depth(self, depth: float):
+        self.create_shape()
+
+    def set_top_edge(self, value):
+        self.create_shape()
+
+    def set_bottom_edge(self, value):
+        self.create_shape()

declaracad/occ/shape.py

@@ -11,12 +11,14 @@
 @author: jrm
 """
 from math import pi
-from typing import Any, ClassVar, Optional
+from typing import Any, ClassVar, Optional, Union
 
 from atom.api import (
+    Atom,
     Bool,
     Coerced,
     Dict,
+    Enum,
     Event,
     Float,
     FloatRange,
@@ -246,6 +248,43 @@ def set_itx(self, itx):
         raise NotImplementedError
 
 
+class HoleEdgeStyle(Atom):
+    kind = Enum("chamfer", "cone")
+    distance = Float(strict=False)
+    distance2 = Float(strict=False)
+
+    def __init__(self, *args, **kwargs):
+        if len(args) == 1 and isinstance(args[0], tuple):
+            value = args[0]
+            n = len(value)
+            if n == 3:
+                kind, distance, distance2 = value
+                super().__init__(kind=kind, distance=distance, distance2=distance2)
+                return
+            elif n == 2:
+                kind, distance = value
+                super().__init__(kind=kind, distance=distance)
+                return
+        super().__init__(*args, **kwargs)
+
+
+class ProxyHole(ProxyShape):
+    #: A reference to the shape declaration.
+    declaration = ForwardTyped(lambda: Hole)
+
+    def set_diameter(self, diameter: float):
+        raise NotImplementedError
+
+    def set_depth(self, depth: float):
+        raise NotImplementedError
+
+    def set_top_edge(self, value: HoleEdgeStyle):
+        raise NotImplementedError
+
+    def set_bottom_edge(self, value: HoleEdgeStyle):
+        raise NotImplementedError
+
+
 class ProxyRevol(ProxyShape):
     #: A reference to the shape declaration.
     declaration = ForwardTyped(lambda: Revol)
@@ -1045,6 +1084,52 @@ def _update_proxy(self, change: dict[str, Any]):
         super(Wedge, self)._update_proxy(change)
 
 
+class Hole(Shape):
+    """A primitive Hole shape.
+
+    Attributes
+    ----------
+
+    diameter: Float
+        The diameter of the hole.
+    depth: Float
+        The depth of the hole.
+    top_edge: Float | Tuple[Float, Float]
+        If negative, add a chamfer to the top of the hole. If positive add a cone.
+    bottom_edge: Float | Tuple[Float, Float]
+        If negative, add a chamfer on the bottom of the hole. If positive add a cone.
+
+    Examples
+    --------
+
+    Hole:
+        diameter = 4
+        depth = 20
+        top_edge = ('chamfer', 0.5)
+        bottom_edge =('cone', 0.5)
+
+    """
+
+    #: Proxy shape
+    proxy = Typed(ProxyHole)
+
+    #: Hole diameter
+    diameter = d_(Float(1, strict=False)).tag(view=True)
+
+    #: Hole depth
+    depth = d_(Float(1, strict=False)).tag(view=True)
+
+    #: Top edge style
+    top_edge = d_(Coerced(HoleEdgeStyle))
+
+    #: Bottom chamfer of the hole
+    bottom_edge = d_(Coerced(HoleEdgeStyle))
+
+    @observe("diameter", "depth", "top_edge", "bottom_edge")
+    def _update_proxy(self, change: dict[str, Any]):
+        super()._update_proxy(change)
+
+
 class Revol(Shape):
     """A Revol creates a shape by revolving a profile about an axis.
 

examples/holes.enaml

@@ -0,0 +1,44 @@
+# Created in DeclaraCAD
+from declaracad.occ.api import *
+
+enamldef Assembly(Part):
+    Axis:
+        pass
+    Cut:
+        Box: box:
+             position = (-dx/2, -dy/2)
+             dx = 50
+             dy = 60
+             dz = 10
+        Hole: center_through_hole:
+            # A hole with no top_edge or bottom_edge styles
+            # defined is the same as a Cylinder except the diameter
+            # and depth are used instead of radius and height
+            diameter = 10
+            depth = box.dz
+        Hole: center_hole:
+            # Defining the top edge as "cone" 1 adds a cone
+            # to the top of the hole which when cut from the box
+            # makes it chamfered by the cone distance.
+            position = (0, 0, 2)
+            diameter = 20
+            depth = box.dz-self.z
+            top_edge = ("cone", 1)
+            bottom_edge = ("chamfer", 2)
+
+        Looper: corner_holes:
+            attr offset = 8
+            iterable = [
+                (box.dx/2-offset, box.dy/2-offset),
+                (-box.dx/2+offset, box.dy/2-offset),
+                (-box.dx/2+offset, -box.dy/2+offset),
+                (box.dx/2-offset, -box.dy/2+offset),
+            ]
+            Hole:
+                position = loop.item
+                diameter = 6
+                depth = box.dz
+                # Defining the top edge as "cone" 1 adds a cone
+                # to the top of the hole which when cut from the box
+                # makes it chamfered by the cone distance.
+                top_edge = ("cone", 1)