Function main

src/examples/IfcAdvancedHouse.cpp:58–137

void createGroundShape(TopoDS_Shape& shape);

int main() {

	// The IfcHierarchyHelper is a subclass of the regular IfcFile that provides several
	// convenience functions for working with geometry in IFC files.
	IfcHierarchyHelper<IfcSchema> file;
	file.header().file_name()->setname("IfcAdvancedHouse.ifc");

	IfcSchema::IfcBuilding* building = file.addBuilding();
	// By adding a building, a hierarchy has been automatically created that consists of the following
	// structure: IfcProject > IfcSite > IfcBuilding

	// Lateron changing the name of the IfcProject can be done by obtaining a reference to the 
	// project, which has been created automatically.
	file.getSingle<IfcSchema::IfcProject>()->setName("IfcAdvancedHouse"s);

	// To demonstrate the ability to serialize arbitrary opencascade solids a building envelope is
	// constructed by applying boolean operations. Naturally, in IFC, building elements should be 
	// modeled separately, with rich parametric and relational semantics. Creating geometry in this
	// way does not preserve any history and is merely a demonstration of technical capabilities.
	TopoDS_Shape outer =   BRepPrimAPI_MakeBox(gp_Pnt(-5000., -180., -2000.), gp_Pnt(5000., 5180., 3000.)).Shape();
	TopoDS_Shape inner =   BRepPrimAPI_MakeBox(gp_Pnt(-4640.,  180.,     0.), gp_Pnt(4640., 4820., 3000.)).Shape();
	TopoDS_Shape window1 = BRepPrimAPI_MakeBox(gp_Pnt(-5000., -180.,   400.), gp_Pnt( 500., 1180., 2000.)).Shape();
	TopoDS_Shape window2 = BRepPrimAPI_MakeBox(gp_Pnt( 2070., -180.,   400.), gp_Pnt(3930.,  180., 2000.)).Shape();

	TopoDS_Shape building_shell = BRepAlgoAPI_Cut(
		BRepAlgoAPI_Cut(
			BRepAlgoAPI_Cut(outer, inner),
			window1
			),
		window2
	);

	// Since the solid consists only of planar faces and straight edges it can be serialized as an
	// IfcFacetedBRep. If it would not be a polyhedron, serialise() can only be successful when linked
	// to the IFC4 model and with `advanced` set to `true` which introduces IfcAdvancedFace. It would
	// return `0` otherwise.
	IfcSchema::IfcProductDefinitionShape* building_shape = IfcGeom::serialise(STRINGIFY(IfcSchema), building_shell, false)->as<IfcSchema::IfcProductDefinitionShape>();
	
	file.addEntity(building_shape);
	IfcSchema::IfcRepresentation* rep = *building_shape->Representations()->begin();
	rep->setContextOfItems(file.getRepresentationContext("model"));

	building->setRepresentation(building_shape);

	// A pale white colour is assigned to the building.
	setSurfaceColour(file, building_shape, 0.75, 0.73, 0.68);

	// For the ground mesh of the IfcSite we will use a Nurbs surface created in Open Cascade. Only
	// in IFC4 the surface can be directly serialized. In IFC2X3 the it will have to be tessellated.
	TopoDS_Shape shape;
	createGroundShape(shape);

	auto ground_representation = IfcGeom::serialise(STRINGIFY(IfcSchema), shape, true);
	if (!ground_representation) {
		ground_representation = IfcGeom::tesselate(STRINGIFY(IfcSchema), shape, 100.);
	}
	file.getSingle<IfcSchema::IfcSite>()->setRepresentation(ground_representation->as<IfcSchema::IfcProductDefinitionShape>());