Accept IfcBooleanResult operands that convert to set of shapes in IfcOpenShell rather than a single shape (i.e IfcShellBasedSurfaceModel, IfcFaceBasedSurfaceModel, IfcFacetedBrep, IfcGeometricSet)

src/ifcgeom/IfcGeom.h

@@ -84,6 +84,7 @@ namespace IfcGeom {
 	bool convert_shapes(const IfcUtil::IfcBaseClass* L, IfcRepresentationShapeItems& result);
 	bool is_shape_collection(const IfcUtil::IfcBaseClass* L);
 	bool convert_shape(const IfcUtil::IfcBaseClass* L, TopoDS_Shape& result);
+	bool flatten_shape_list(const IfcGeom::IfcRepresentationShapeItems& shapes, TopoDS_Shape& result, bool fuse);
 	bool convert_wire(const IfcUtil::IfcBaseClass* L, TopoDS_Wire& result);
 	bool convert_curve(const IfcUtil::IfcBaseClass* L, Handle(Geom_Curve)& result);
 	bool convert_face(const IfcUtil::IfcBaseClass* L, TopoDS_Shape& result);

src/ifcgeom/IfcGeomFunctions.cpp

@@ -69,6 +69,7 @@
 #include <BRepBuilderAPI_MakeSolid.hxx>
 #include <BRepPrimAPI_MakeHalfSpace.hxx>
 #include <BRepAlgoAPI_Cut.hxx>
+#include <BRepAlgoAPI_Fuse.hxx>
 
 #include <ShapeFix_Shape.hxx>
 #include <ShapeFix_ShapeTolerance.hxx>
@@ -691,4 +692,61 @@ bool IfcGeom::fill_nonmanifold_wires_with_planar_faces(TopoDS_Shape& shape) {
 	} catch(...) {}
 
 	return true;
-}
+}
+
+bool IfcGeom::flatten_shape_list(const IfcGeom::IfcRepresentationShapeItems& shapes, TopoDS_Shape& result, bool fuse) {
+	TopoDS_Compound compound;
+	BRep_Builder builder;
+	builder.MakeCompound(compound);
+
+	result = TopoDS_Shape();
+			
+	for ( IfcGeom::IfcRepresentationShapeItems::const_iterator it = shapes.begin(); it != shapes.end(); ++ it ) {
+		TopoDS_Shape merged;
+		const TopoDS_Shape& s = it->Shape();
+		if (fuse) {
+			IfcGeom::ensure_fit_for_subtraction(s, merged);
+		} else {
+			merged = s;
+		}
+		const gp_GTrsf& trsf = it->Placement();
+		bool trsf_valid = false;
+		gp_Trsf _trsf;
+		try {
+			_trsf = trsf.Trsf();
+			trsf_valid = true;
+		} catch (...) {}
+		const TopoDS_Shape moved_shape = trsf_valid ? merged.Moved(_trsf) :
+			BRepBuilderAPI_GTransform(merged,trsf,true).Shape();
+
+		if (shapes.size() == 1) {
+			result = moved_shape;
+			return true;
+		}
+
+		if (fuse) {
+			if (result.IsNull()) {
+				result = moved_shape;
+			} else {
+				BRepAlgoAPI_Fuse brep_fuse(result, moved_shape);
+				if ( brep_fuse.IsDone() ) {
+					TopoDS_Shape fused = brep_fuse;
+
+					ShapeFix_Shape fix(result);
+					fix.Perform();
+					result = fix.Shape();
+		
+					bool is_valid = BRepCheck_Analyzer(result).IsValid() != 0;
+					if ( is_valid ) {
+						result = fused;
+					} 
+				}
+			}
+		} else {
+			builder.Add(compound,moved_shape);
+		}
+	}
+
+	return !result.IsNull();
+}
+	

src/ifcgeom/IfcGeomShapes.cpp

@@ -242,19 +242,34 @@ bool IfcGeom::convert(const IfcSchema::IfcShellBasedSurfaceModel* l, IfcRepresen
 
 bool IfcGeom::convert(const IfcSchema::IfcBooleanResult* l, TopoDS_Shape& shape) {
 	TopoDS_Shape s1, s2;
+	IfcRepresentationShapeItems items1, items2;
 	TopoDS_Wire boundary_wire;
 	IfcSchema::IfcBooleanOperand operand1 = l->FirstOperand();
 	IfcSchema::IfcBooleanOperand operand2 = l->SecondOperand();
 	bool is_halfspace = operand2->is(IfcSchema::Type::IfcHalfSpaceSolid);
 
-	if ( ! IfcGeom::convert_shape(operand1,s1) )
-		return false;
+	if ( is_shape_collection(operand1) ) {
+		if (!(convert_shapes(operand1, items1) && flatten_shape_list(items1, s1, true))) {
+			return false;
+		}
+	} else {
+		if ( ! IfcGeom::convert_shape(operand1,s1) ) {
+			return false;
+		}
+	}
 
 	const double first_operand_volume = shape_volume(s1);
 	if ( first_operand_volume <= ALMOST_ZERO )
 		Logger::Message(Logger::LOG_WARNING,"Empty solid for:",l->FirstOperand()->entity);
 
-	if ( !IfcGeom::convert_shape(l->SecondOperand(),s2) ) {
+	bool shape2_processed = false;
+	if ( is_shape_collection(operand2) ) {
+		shape2_processed = convert_shapes(operand2, items2) && flatten_shape_list(items2, s2, true);
+	} else {
+		shape2_processed = IfcGeom::convert_shape(operand2,s2);
+	}
+
+	if (!shape2_processed) {
 		shape = s1;
 		Logger::Message(Logger::LOG_ERROR,"Failed to convert SecondOperand of:",l->entity);
 		return true;