--section-height-from-storeys

src/ifcconvert/IfcConvert.cpp

@@ -325,6 +325,7 @@ int main(int argc, char** argv) {
 #endif
     short precision;
 	double section_height;
+
     po::options_description serializer_options("Serialization options");
     serializer_options.add_options()
 #ifdef HAVE_ICU
@@ -337,6 +338,7 @@ int main(int argc, char** argv) {
             "output will be scaled. Only used when converting to SVG.")
 		("section-height", po::value<double>(&section_height),
 		    "Specifies the cut section height for SVG 2D geometry.")
+		("section-height-from-storeys", "Derives section height from storey elevation. Use --section-height to override default offset of 1")
 		("use-element-names",
             "Use entity names instead of unique IDs for naming elements upon serialization. "
             "Applicable for OBJ, DAE, and SVG output.")
@@ -695,19 +697,6 @@ int main(int argc, char** argv) {
 	} else if (output_extension == SVG) {
 		settings.set(IfcGeom::IteratorSettings::DISABLE_TRIANGULATION, true);
 		serializer = boost::make_shared<SvgSerializer>(IfcUtil::path::to_utf8(output_temp_filename), settings);
-		if (vmap.count("section-height") != 0) {
-			Logger::Notice("Overriding section height");
-			static_cast<SvgSerializer*>(serializer.get())->setSectionHeight(section_height);
-		}
-		if (vmap.count("print-space-names") != 0) {
-			static_cast<SvgSerializer*>(serializer.get())->setPrintSpaceNames(true);
-		}
-		if (vmap.count("print-space-areas") != 0) {
-			static_cast<SvgSerializer*>(serializer.get())->setPrintSpaceAreas(true);
-		}
-		if (bounding_width.is_initialized() && bounding_height.is_initialized()) {
-            static_cast<SvgSerializer*>(serializer.get())->setBoundingRectangle(bounding_width.get(), bounding_height.get());
-		}
 	} else {
         cerr_ << "[Error] Unknown output filename extension '" << output_extension << "'\n";
 		write_log(!quiet);
@@ -825,6 +814,28 @@ int main(int argc, char** argv) {
 
 	serializer->setFile(context_iterator.file());
 
+	if (output_extension == SVG) {
+		if (vmap.count("section-height-from-storeys") != 0) {
+			if (vmap.count("section-height")) {
+				static_cast<SvgSerializer*>(serializer.get())->setSectionHeightsFromStoreys(section_height);
+			} else {
+				static_cast<SvgSerializer*>(serializer.get())->setSectionHeightsFromStoreys();
+			}
+		} else if (vmap.count("section-height") != 0) {
+			Logger::Notice("Overriding section height");
+			static_cast<SvgSerializer*>(serializer.get())->setSectionHeight(section_height);
+		}
+		if (vmap.count("print-space-names") != 0) {
+			static_cast<SvgSerializer*>(serializer.get())->setPrintSpaceNames(true);
+		}
+		if (vmap.count("print-space-areas") != 0) {
+			static_cast<SvgSerializer*>(serializer.get())->setPrintSpaceAreas(true);
+		}
+		if (bounding_width.is_initialized() && bounding_height.is_initialized()) {
+			static_cast<SvgSerializer*>(serializer.get())->setBoundingRectangle(bounding_width.get(), bounding_height.get());
+		}
+	}
+
     if (convert_back_units) {
 		serializer->setUnitNameAndMagnitude(context_iterator.unit_name(), static_cast<float>(context_iterator.unit_magnitude()));
 	} else {

src/serializers/SvgSerializer.cpp

@@ -290,32 +290,40 @@ SvgSerializer::path_object& SvgSerializer::start_path(IfcUtil::IfcBaseEntity* st
 	return p;
 }
 
+#include <Bnd_Box.hxx>
+#include <BRepBndLib.hxx>
+
 void SvgSerializer::write(const IfcGeom::BRepElement<real_t>* o)
 {
-	IfcUtil::IfcBaseEntity* storey = storey_;
+	std::vector<std::pair<double, IfcUtil::IfcBaseEntity*>> section_heights_storage;
-	boost::optional<double> storey_elevation = boost::none;
+	const std::vector<std::pair<double, IfcUtil::IfcBaseEntity*>>* section_heights_used = &section_heights_storage;
 
+	if (section_heights) {
+		section_heights_used = section_heights.get_ptr();
+	} else {
 		for (const auto& p : o->parents()) {
 			if (p->type() == "IfcBuildingStorey") {
 				try {
 					const IfcGeom::ElementSettings& settings = o->geometry().settings();
 					double e = *p->product()->get("Elevation");
-				storey_elevation = e * settings.unit_magnitude();
+					double storey_elevation = e * settings.unit_magnitude();
+					section_heights_storage.push_back({ storey_elevation + 1. , p->product() });
 				} catch (...) {
 					continue;
 				}
-			storey = p->product();
 				break;
 			}
 		}
 
-	// With a global section height, building storeys are not a requirement.
+		if (section_heights_storage.empty()) {
-	if (!storey && !section_height) {
 			Logger::Warning("No global section height and unable to determine building storey for:", o->product());
 			return;
 		}
+	}
 
-	path_object& p = start_path(storey, nameElement(o));
+	for (auto& pair : *section_heights_used) {
+		auto cut_z = pair.first;
+		auto storey = pair.second;
 
 		// SVG has a coordinate system with the origin in the *upper*-left corner
 		// therefore we mirror the shape along the XZ-plane.
@@ -331,52 +339,50 @@ void SvgSerializer::write(const IfcGeom::BRepElement<real_t>* o)
 
 		TopoDS_Face largest_closed_wire_face;
 		double largest_closed_wire_area = 0.;
+		path_object* po;
 
 		// Iterate over components of compound to have better chance of matching section edges to closed wires
 		for (; it.More(); it.Next()) {
 
 			const TopoDS_Shape& subshape = it.Value();
 			
-		const double inf = std::numeric_limits<double>::infinity();
+			Bnd_Box bb;
-		double zmin = inf;
+			BRepBndLib::Add(it.Value(), bb);
-		double zmax = -inf;
-		{TopExp_Explorer exp(subshape, TopAbs_VERTEX);
-		for (; exp.More(); exp.Next()) {
-			const TopoDS_Vertex& vertex = TopoDS::Vertex(exp.Current());
-			gp_Pnt pnt = BRep_Tool::Pnt(vertex);
-			if (pnt.Z() < zmin) { zmin = pnt.Z(); }
-			if (pnt.Z() > zmax) { zmax = pnt.Z(); }
-		}}
 
-		// Empty geometry, no vertices encountered
+			// Empty geometry
-		if (zmin == inf) continue;
+			if (bb.IsVoid()) {
+				continue;
+			}
+
+			double x1, y1, zmin, x2, y2, zmax;
+			bb.Get(x1, y1, zmin, x2, y2, zmax);
 						
 			// Determine slicing plane z coordinate, priority:
 			// 1) explicitly set global section height
 			// 2) containing building storey elevation + 1m
 			// 3) zmin (from geometry bounding box) + 1m
-		double cut_z;
+
-		if (section_height) {
+			if (std::isnan(cut_z)) {
-			cut_z = section_height.get();
-		} else if (storey_elevation && !(zmin > *storey_elevation || zmax < *storey_elevation)) {
-			cut_z = storey_elevation.get() + 1.;
-		} else {
 				cut_z = zmin + 1.;
 			}
 			
 			// No intersection with bounding box, fail early
 			if (zmin > cut_z || zmax < cut_z) continue;
 
+			po = &start_path(storey, nameElement(o));
+
 			// Create a horizontal cross section 1 meter above the bottom point of the shape		
 			const gp_Pln pln(gp_Pnt(0, 0, cut_z), gp::DZ());
 			TopoDS_Shape result = BRepAlgoAPI_Section(subshape, pln);
 
 			Handle(TopTools_HSequenceOfShape) edges = new TopTools_HSequenceOfShape();
 			Handle(TopTools_HSequenceOfShape) wires = new TopTools_HSequenceOfShape();
-		{TopExp_Explorer exp(result, TopAbs_EDGE);
+			{
+				TopExp_Explorer exp(result, TopAbs_EDGE);
 				for (; exp.More(); exp.Next()) {
 					edges->Append(exp.Current());
-		}}
+				}
+			}
 			ShapeAnalysis_FreeBounds::ConnectEdgesToWires(edges, 1e-5, false, wires);
 
 			gp_Pnt prev;
@@ -400,7 +406,7 @@ void SvgSerializer::write(const IfcGeom::BRepElement<real_t>* o)
 					}
 
 				}
-			write(p, wire);
+				write(*po, wire);
 			}
 		}
 
@@ -470,7 +476,6 @@ void SvgSerializer::write(const IfcGeom::BRepElement<real_t>* o)
 					labels.push_back(ss.str() + "m&#178;");
 				}
 
-			path_object& po = p;
 				util::string_buffer path;
 				// dominant-baseline="central" is not well supported in IE.
 				// so we add a 0.35 offset to the dy of the tspans
@@ -494,7 +499,8 @@ void SvgSerializer::write(const IfcGeom::BRepElement<real_t>* o)
 					path.add("</tspan>");
 				}
 				path.add("</text>");
-			po.second.push_back(path);
+				po->second.push_back(path);
+			}
 		}
 	}
 }
@@ -635,3 +641,31 @@ void SvgSerializer::setFile(IfcParse::IfcFile* f) {
 		Logger::Warning("No building storeys encountered, output might be invalid or missing");
 	}
 }
+
+void SvgSerializer::setSectionHeight(double h, IfcUtil::IfcBaseEntity* storey) {
+	section_heights.emplace();
+	section_heights->push_back({ h, storey });
+}
+
+void SvgSerializer::setSectionHeightsFromStoreys(double offset) {
+	section_heights.emplace();
+	auto storeys = file->instances_by_type("IfcBuildingStorey");
+	const double lu = file->getUnit("LENGTHUNIT").second;
+	if (storeys && storeys->size() > 0) {
+		for (auto& s : *storeys) {
+			auto attr_value = ((IfcUtil::IfcBaseEntity*)s)->get("Elevation");
+			if (!attr_value->isNull()) {
+				double elev;
+				try {
+					elev = *attr_value;
+				} catch (std::exception& e) {
+					Logger::Error(e);
+					continue;
+				}
+				section_heights->push_back({ elev * lu + offset , (IfcUtil::IfcBaseEntity*)s });
+			}			
+		}
+	} else {
+		section_heights->push_back({ std::numeric_limits<double>::quiet_NaN(), nullptr });
+	}
+}

src/serializers/SvgSerializer.h

@@ -64,7 +64,7 @@ public:
 protected:
 	std::ofstream svg_file;
 	double xmin, ymin, xmax, ymax, width, height;
-	boost::optional<double> section_height;
+	boost::optional<std::vector<std::pair<double, IfcUtil::IfcBaseEntity*>>> section_heights;
 	bool rescale, print_space_names_, print_space_areas_;
 	std::multimap<IfcUtil::IfcBaseEntity*, path_object, storey_sorter> paths;
 	std::vector< boost::shared_ptr<util::string_buffer::float_item> > xcoords;
@@ -99,7 +99,8 @@ public:
     void setUnitNameAndMagnitude(const std::string& /*name*/, float /*magnitude*/) {}
 	void setFile(IfcParse::IfcFile* f);
     void setBoundingRectangle(double width, double height);
-	void setSectionHeight(double h, IfcUtil::IfcBaseEntity* storey = 0) { section_height = h; storey_ = storey; }
+	void setSectionHeight(double h, IfcUtil::IfcBaseEntity* storey = 0);
+	void setSectionHeightsFromStoreys(double offset=1.);
 	void setPrintSpaceNames(bool b) { print_space_names_ = b; }
 	void setPrintSpaceAreas(bool b) { print_space_areas_ = b; }
     std::string nameElement(const IfcGeom::Element<real_t>* elem);