See #5972. You can now remove boolean operations in the stack without deleting operands.

src/bonsai/bonsai/bim/module/model/__init__.py

@@ -88,6 +88,7 @@ classes = (
     opening.HideOpenings,
     opening.PurgeUnusedOpenings,
     opening.RecalculateFill,
+    opening.RemoveBoolean,
     opening.RemoveBooleans,
     opening.ShowBooleans,
     opening.ShowOpenings,

src/bonsai/bonsai/bim/module/model/opening.py

@@ -1144,6 +1144,27 @@ class PurgeUnusedOpenings(Operator, tool.Ifc.Operator):
         return {"FINISHED"}
 
 
+class RemoveBoolean(Operator, tool.Ifc.Operator):
+    bl_idname = "bim.remove_boolean"
+    bl_label = "Remove Boolean"
+    bl_options = {"REGISTER", "UNDO"}
+    bl_description = "Removes the actively selected boolean"
+
+    @classmethod
+    def poll(cls, context):
+        props = context.scene.BIMBooleanProperties
+        return props.active_boolean
+
+    def _execute(self, context):
+        props = context.scene.BIMBooleanProperties
+        ifcopenshell.api.geometry.remove_boolean(
+            tool.Ifc.get(), tool.Ifc.get().by_id(props.active_boolean.ifc_definition_id)
+        )
+        bpy.ops.bim.enable_editing_booleans()
+        rep_obj = bpy.context.scene.BIMGeometryProperties.representation_obj
+        tool.Geometry.reload_representation(rep_obj)
+
+
 # TODO: merge with ProfileDecorator?
 class DecorationsHandler:
     installed = None

src/bonsai/bonsai/bim/module/void/prop.py

@@ -45,3 +45,8 @@ class BIMBooleanProperties(PropertyGroup):
         name="Operator",
         default="DIFFERENCE",
     )
+
+    @property
+    def active_boolean(self):
+        if self.booleans and self.active_boolean_index < len(self.booleans):
+            return self.booleans[self.active_boolean_index]

src/bonsai/bonsai/bim/module/void/ui.py

@@ -176,6 +176,10 @@ class BIM_PT_booleans(Panel):
         row.prop(props, "operator", text="")
         row.operator("bim.add_boolean", text="", icon="ADD")
 
+        row = layout.row(align=True)
+        row.alignment = "RIGHT"
+        row.operator("bim.remove_boolean", text="", icon="X")
+
         self.layout.template_list("BIM_UL_booleans", "", props, "booleans", props, "active_boolean_index")
 
 

src/ifcopenshell-python/ifcopenshell/api/geometry/remove_boolean.py

@@ -20,40 +20,42 @@ import ifcopenshell.util.element
 
 
 def remove_boolean(file: ifcopenshell.file, item: ifcopenshell.entity_instance) -> None:
-    usecase = Usecase()
-    usecase.file = file
-    usecase.settings = {"item": item}
-    return usecase.execute()
+    """Removes a boolean operation without deleting the operands
 
+    The first operand will replace the boolean result itself, and the second
+    operand will be reset as a top level representation item.
 
-class Usecase:
-    def execute(self):
-        item = None
-        for inverse in self.file.get_inverse(self.settings["item"]):
+    This may affect the Items of IfcShapeRepresentation, so it is recommended
+    to run :func:`ifcopenshell.api.geometry.validate_type` after all boolean
+    modifications are complete.
+
+    :param item: This may either be an IfcBooleanResult or an
+        IfcRepresentationItem that is participating in one or more boolean
+        results (in which case all are removed).
+    """
+    if not item.is_a("IfcBooleanResult"):
+        for inverse in file.get_inverse(item):
             if inverse.is_a("IfcBooleanResult"):
-                item = inverse
-                break
+                remove_boolean(file, inverse)
+        return
 
-        representation = self.get_representation(item)
+    representations = []
+    queue = list(file.get_inverse(item))
+    while queue:
+        inverse = queue.pop()
+        if inverse.is_a("IfcShapeRepresentation"):
+            representations.append(inverse)
+        elif inverse.is_a("IfcBooleanResult"):
+            queue.extend(file.get_inverse(inverse))
+        elif inverse.is_a("IfcCsgSolid"):
+            queue.extend(file.get_inverse(inverse))
 
-        first_operand = item.FirstOperand
-        second_operand = item.SecondOperand
-        for inverse in self.file.get_inverse(item):
-            ifcopenshell.util.element.replace_attribute(inverse, item, first_operand)
-        self.file.remove(item)
-        ifcopenshell.util.element.remove_deep2(self.file, second_operand)
+    first = item.FirstOperand
+    second = item.SecondOperand
+    for inverse in file.get_inverse(item):
+        ifcopenshell.util.element.replace_attribute(inverse, item, first)
 
-        item_classes = {i.is_a() for i in representation.Items}
-        if "IfcBooleanResult" in item_classes:
-            representation.RepresentationType = "CSG"
-        elif "IfcBooleanClippingResult" in item_classes:
-            representation.RepresentationType = "Clipping"
-        else:
-            representation.RepresentationType = "SweptSolid"
+    for representation in set(representations):
+        representation.Items = list(representation.Items) + [second]
 
-    def get_representation(self, item):
-        for inverse in self.file.get_inverse(item):
-            if inverse.is_a("IfcShapeRepresentation"):
-                return inverse
-            elif inverse.is_a("IfcRepresentationItem"):
-                return self.get_representation(inverse)
+    file.remove(item)

src/ifcopenshell-python/test/api/geometry/test_remove_boolean.py

@@ -0,0 +1,87 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2023 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# IfcOpenShell 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 Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+
+import test.bootstrap
+import ifcopenshell.api.root
+import ifcopenshell.api.context
+import ifcopenshell.api.geometry
+
+
+class TestRemoveBoolean(test.bootstrap.IFC4):
+    def test_removing_a_single_top_level_boolean(self):
+        ifcopenshell.api.root.create_entity(self.file, ifc_class="IfcProject")
+        model = ifcopenshell.api.context.add_context(self.file, context_type="Model")
+        body = ifcopenshell.api.context.add_context(
+            self.file, context_type="Model", context_identifier="Body", target_view="MODEL_VIEW", parent=model
+        )
+        builder = ifcopenshell.util.shape_builder.ShapeBuilder(self.file)
+        first = builder.sphere()
+        second = builder.block()
+        rep = builder.get_representation(body, [first, second])
+
+        booleans = ifcopenshell.api.geometry.add_boolean(self.file, first, [second])
+        ifcopenshell.api.geometry.remove_boolean(self.file, booleans[0])
+        assert set(rep.Items) == {first, second}
+        assert not self.file.by_type("IfcBooleanResult")
+
+
+    def test_removing_a_top_level_nested_boolean(self):
+        ifcopenshell.api.root.create_entity(self.file, ifc_class="IfcProject")
+        model = ifcopenshell.api.context.add_context(self.file, context_type="Model")
+        body = ifcopenshell.api.context.add_context(
+            self.file, context_type="Model", context_identifier="Body", target_view="MODEL_VIEW", parent=model
+        )
+        builder = ifcopenshell.util.shape_builder.ShapeBuilder(self.file)
+        first = builder.sphere()
+        second1 = builder.block()
+        second2 = builder.block()
+        rep = builder.get_representation(body, [first])
+
+        ifcopenshell.api.geometry.add_boolean(self.file, first, [second1, second2])
+        ifcopenshell.api.geometry.remove_boolean(self.file, second2)
+        assert len(rep.Items) == 2
+        assert second2 in rep.Items
+        boolean = self.file.by_type("IfcBooleanResult")[0]
+        assert boolean in rep.Items
+        assert boolean.FirstOperand == first
+        assert boolean.SecondOperand == second1
+
+    def test_removing_a_nested_boolean(self):
+        ifcopenshell.api.root.create_entity(self.file, ifc_class="IfcProject")
+        model = ifcopenshell.api.context.add_context(self.file, context_type="Model")
+        body = ifcopenshell.api.context.add_context(
+            self.file, context_type="Model", context_identifier="Body", target_view="MODEL_VIEW", parent=model
+        )
+        builder = ifcopenshell.util.shape_builder.ShapeBuilder(self.file)
+        first = builder.sphere()
+        second1 = builder.block()
+        second2 = builder.block()
+        rep = builder.get_representation(body, [first])
+
+        ifcopenshell.api.geometry.add_boolean(self.file, first, [second1, second2])
+        ifcopenshell.api.geometry.remove_boolean(self.file, second1)
+        assert len(rep.Items) == 2
+        assert second1 in rep.Items
+        boolean = self.file.by_type("IfcBooleanResult")[0]
+        assert boolean in rep.Items
+        assert boolean.FirstOperand == first
+        assert boolean.SecondOperand == second2
+
+
+class TestRemoveBooleanIFC2X3(test.bootstrap.IFC2X3, TestRemoveBoolean):
+    pass