#2237 workaround for openings on extrusions of compound profiles

src/ifcgeom/IfcGeomFunctions.cpp

@@ -1377,20 +1377,43 @@ bool IfcGeom::Kernel::convert_openings_fast(const IfcSchema::IfcProduct* entity,
 	// Iterate over the shapes of the IfcProduct
 	for (IfcGeom::IfcRepresentationShapeItems::const_iterator it3 = entity_shapes.begin(); it3 != entity_shapes.end(); ++it3) {
 
-		bool is_manifold = Kernel::is_manifold(it3->Shape());
+		TopoDS_Compound C;
+		BRep_Builder B;
+		B.MakeCompound(C);
+		TopoDS_Shape combined_result;
+
+		std::list<TopoDS_Shape> parts;
+
+		bool is_multiple = it3->Shape().ShapeType() == TopAbs_COMPOUND && TopoDS_Iterator(it3->Shape()).More() && util::is_nested_compound_of_solid(it3->Shape());
+
+		if (is_multiple) {
+			TopoDS_Iterator sit(it3->Shape());
+			for (; sit.More(); sit.Next()) {
+				parts.push_back(sit.Value());
+			}
+		} else {
+			parts.push_back(it3->Shape());
+		}
+
+		for (auto& entity_part : parts) {
+
+
+			bool is_manifold = Kernel::is_manifold(entity_part);
 
 			if (!is_manifold) {
 				Logger::Warning("Non-manifold first operand");
 			}
 
+			TopoDS_Shape entity_part_result;			
+
 			for (int as_shell = 0; as_shell < 2; ++as_shell) {
 
 				TopoDS_Shape entity_shape_solid;
 				TopoDS_Shape entity_shape_unlocated;
 				if (as_shell) {
-				entity_shape_unlocated = it3->Shape();
+					entity_shape_unlocated = entity_part;
 				} else {
-				entity_shape_unlocated = ensure_fit_for_subtraction(it3->Shape(), entity_shape_solid);
+					entity_shape_unlocated = ensure_fit_for_subtraction(entity_part, entity_shape_solid);
 				}
 				const gp_GTrsf& entity_shape_gtrsf = it3->Placement();
 				if (entity_shape_gtrsf.Form() == gp_Other) {
@@ -1441,12 +1464,26 @@ bool IfcGeom::Kernel::convert_openings_fast(const IfcSchema::IfcProduct* entity,
 					continue;
 				}
 
-			cut_shapes.push_back(IfcGeom::IfcRepresentationShapeItem(it3->ItemId(), result, it3->StylePtr()));
+				entity_part_result = result;
 
 				// For manifold first operands we're not even going to try if processing
 				// as loose faces gives a better result.
 				break;
 			}
+
+			if (is_multiple) {
+				B.Add(C, entity_part_result);
+			} else {
+				combined_result = entity_part_result;
+			}
+
+		}
+
+		if (is_multiple) {
+			combined_result = C;
+		}
+
+		cut_shapes.push_back(IfcGeom::IfcRepresentationShapeItem(it3->ItemId(), combined_result, it3->StylePtr()));
 	}
 	return true;
 }

src/ifcgeom/IfcGeomShapes.cpp

@@ -541,24 +541,6 @@ bool IfcGeom::Kernel::convert(const IfcSchema::IfcShellBasedSurfaceModel* l, Ifc
 	return true;
 }
 
-namespace {
-	bool is_nested_compound_of_solid(const TopoDS_Shape& s, int depth=0) {
-		if (s.ShapeType() == TopAbs_COMPOUND) {
-			TopoDS_Iterator it(s);
-			for (; it.More(); it.Next()) {
-				if (!is_nested_compound_of_solid(it.Value(), depth + 1)) {
-					return false;
-				}
-			}
-			return true;
-		} else if (s.ShapeType() == TopAbs_SOLID) {
-			return depth > 0;
-		} else {
-			return false;
-		}
-	}
-}
-
 bool IfcGeom::Kernel::convert(const IfcSchema::IfcBooleanResult* l, TopoDS_Shape& shape) {
 
 	TopoDS_Shape s1;
@@ -715,7 +697,7 @@ bool IfcGeom::Kernel::convert(const IfcSchema::IfcBooleanResult* l, TopoDS_Shape
 	
 	bool valid_result;
 
-	if (s1.ShapeType() == TopAbs_COMPOUND && TopoDS_Iterator(s1).More() && is_nested_compound_of_solid(s1)) {
+	if (s1.ShapeType() == TopAbs_COMPOUND && TopoDS_Iterator(s1).More() && util::is_nested_compound_of_solid(s1)) {
 		TopoDS_Compound C;
 		BRep_Builder B;
 		B.MakeCompound(C);

src/ifcgeom_schema_agnostic/Kernel.cpp

@@ -354,3 +354,19 @@ bool IfcGeom::Kernel::is_manifold(const TopoDS_Shape& a) {
 		return true;
 	}
 }
+
+bool IfcGeom::util::is_nested_compound_of_solid(const TopoDS_Shape& s, int depth) {
+	if (s.ShapeType() == TopAbs_COMPOUND) {
+		TopoDS_Iterator it(s);
+		for (; it.More(); it.Next()) {
+			if (!is_nested_compound_of_solid(it.Value(), depth + 1)) {
+				return false;
+			}
+		}
+		return true;
+	} else if (s.ShapeType() == TopAbs_SOLID) {
+		return depth > 0;
+	} else {
+		return false;
+	}
+}

src/ifcgeom_schema_agnostic/Kernel.h

@@ -130,6 +130,10 @@ namespace IfcGeom {
 
 		KernelFactoryImplementation& kernel_implementations();
 	}
+
+	namespace util {
+		bool is_nested_compound_of_solid(const TopoDS_Shape& s, int depth = 0);
+	}
 }
 
 #endif