Adds new simplified alignment example that makes us of the alignment …

…helper functions

src/examples/CMakeLists.txt

@@ -36,3 +36,8 @@ endif()
 ADD_EXECUTABLE(IfcAlignment IfcAlignment.cpp)
 TARGET_LINK_LIBRARIES(IfcAlignment ${IFCOPENSHELL_LIBRARIES})
 set_target_properties(IfcAlignment PROPERTIES FOLDER Examples)
+
+
+ADD_EXECUTABLE(IfcSimplifiedAlignment IfcSimplifiedAlignment.cpp)
+TARGET_LINK_LIBRARIES(IfcSimplifiedAlignment ${IFCOPENSHELL_LIBRARIES})
+set_target_properties(IfcSimplifiedAlignment PROPERTIES FOLDER Examples)

src/examples/IfcAlignment.cpp

@@ -23,6 +23,9 @@
 // https://www.fhwa.dot.gov/bridge/pubs/hif22034.pdf
 //
 // Sections and page number for this document are cited in the code comments.
+//
+// This examples differs from IfcSimplifiedAlignment because it builds the
+// alignment explicitly
 
 // Disable warnings coming from IfcOpenShell
 #pragma warning(disable : 4018 4267 4250 4984 4985)
@@ -409,6 +412,7 @@ int main() {
 
     // start by defining a gradient curve composed of the vertical curve segments and associated with the horizontal composite curve
     auto gradient_curve = new Schema::IfcGradientCurve(vertical_curve_segments, false, composite_curve, nullptr);
+    file.addEntity(gradient_curve);
 
     // the gradient curve is a representation item
     typename aggregate_of<typename Schema::IfcRepresentationItem>::ptr profile_representation_items(new aggregate_of<typename Schema::IfcRepresentationItem>());

src/examples/IfcSimplifiedAlignment.cpp

@@ -0,0 +1,160 @@
+/********************************************************************************
+ *                                                                              *
+ * This file is part of IfcOpenShell.                                           *
+ *                                                                              *
+ * IfcOpenShell is free software: you can redistribute it and/or modify         *
+ * it under the terms of the Lesser GNU General Public License as published by  *
+ * the Free Software Foundation, either version 3.0 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                 *
+ * Lesser GNU General Public License for more details.                          *
+ *                                                                              *
+ * You should have received a copy of the Lesser GNU General Public License     *
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.         *
+ *                                                                              *
+ ********************************************************************************/
+
+// This example illustrates the basic of building an alignment model.
+// The alignment is based on "Bridge Geometry Manual", April 2022
+// US Department of Transportation, Federal Highway Administration (FHWA)
+// https://www.fhwa.dot.gov/bridge/pubs/hif22034.pdf
+//
+// Sections and page number for this document are cited in the code comments.
+//
+// This examples differs from IfcAlignment because it uses utility methods
+// to simplify alignment construction
+
+// Disable warnings coming from IfcOpenShell
+#pragma warning(disable : 4018 4267 4250 4984 4985)
+
+#include "../ifcparse/Ifc4x3_add2.h"
+#include "../ifcparse/IfcAlignmentHelper.h"
+
+#include <fstream>
+
+#define Schema Ifc4x3_add2
+
+// performs basic project setup including created the IfcProject object
+// and initializing the project units to FEET
+Schema::IfcProject* setup_project(IfcHierarchyHelper<Schema>& file) {
+    std::vector<std::string> file_description;
+    file_description.push_back("ViewDefinition[Alignment-basedReferenceView]");
+    file.header().file_description().description(file_description);
+
+    auto project = file.addProject();
+    project->setName(std::string("FHWA Bridge Geometry Manual Example Alignment"));
+
+    // set up project units for feet
+    // the call to file.addProject() sets up length units as millimeter.
+    auto units_in_context = project->UnitsInContext();
+    auto units = units_in_context->Units();
+    auto begin = units->begin();
+    auto iter = begin;
+    auto end = units->end();
+    for (; iter != end; iter++) {
+        auto unit = *iter;
+        if (unit->as<Schema::IfcSIUnit>() && unit->as<Schema::IfcSIUnit>()->UnitType() == Schema::IfcUnitEnum::IfcUnit_LENGTHUNIT) {
+            auto dimensions = new Schema::IfcDimensionalExponents(1, 0, 0, 0, 0, 0, 0);
+            file.addEntity(dimensions);
+
+            auto conversion_factor = new Schema::IfcMeasureWithUnit(new Schema::IfcLengthMeasure(304.80), unit->as<Schema::IfcSIUnit>());
+            file.addEntity(conversion_factor);
+
+            auto conversion_based_unit = new Schema::IfcConversionBasedUnit(dimensions, Schema::IfcUnitEnum::IfcUnit_LENGTHUNIT, "FEET", conversion_factor);
+            file.addEntity(conversion_based_unit);
+
+            units->remove(unit);                // remove the millimeter unit
+            units->push(conversion_based_unit); // add the feet unit
+            units_in_context->setUnits(units);  // update the UnitsInContext
+
+            break; // Done!, the length unit was found, so break out of the loop
+        }
+    }
+
+    return project;
+}
+
+int main() {
+    IfcHierarchyHelper<Schema> file;
+
+    auto project = setup_project(file);
+
+    //
+    // Define horizontal alignment
+    //
+
+    // PI Data
+    // B.1.1 pg 211
+    std::vector<std::pair<double, double>> points{
+        { 500.0, 2500.0}, // beginning
+        {3340.0,  660.0}, // Point of intersection (PI), Curve #1
+        {4340.0, 5000.0}, // Point of intersection (PI), Curve #2
+        {7600.0, 4560.0}, // Point of intersection (PI), Curve #3
+        {8480.0, 2010.0}  // ending
+    };
+
+    // Curve Data
+    // B.1.3 pg 212
+    std::vector<double> radii{ 1000,1250,950 };
+
+    //
+    // Define vertical profile segments
+    //
+
+    // Vertical Profile Data
+    // Figure B.2 pg 213
+    double xStart = 10000.0; // subtract xStart so the points are distance along, not station
+    std::vector<std::pair<double,double>> vpoints {
+        {10000.0-xStart,100.0}, // Vertical point of beginning (VPOB)
+        {12000.0-xStart,135.0}, // Point of vertical intersection (VPI), Curve #1
+        {15000.0-xStart,105.0}, // Point of vertical intersection (VPI), Curve #2
+        {17400.0-xStart,153.0}, // Point of vertical intersection (VPI), Curve #3
+        {19800.0-xStart,105.0}, // Point of vertical intersection (VPI), Curve #4
+        {22800.0-xStart, 90.0}  // Vertical poitn of ending (VPOE)
+    };
+
+    // Vertical Curve Lengths
+    // Figure B.2 pg 213
+    std::vector<double> vclengths{1600.0, 1200.0, 2000.0, 800.0};
+
+    // Use utility function to create alignment
+    auto alignment = addAlignment(file, "Example Alignment", points, radii, vpoints, vclengths);
+
+    // Define the alignment's relationship with the project
+
+    // IFC 4.1.4.1.1 "Every IfcAlignment must be related to IfcProject using the IfcRelAggregates relationship"
+    // https://standards.buildingsmart.org/IFC/RELEASE/IFC4_3/HTML/concepts/Object_Composition/Aggregation/Alignment_Aggregation_To_Project/content.html
+    // IfcProject <-> IfcRelAggregates <-> IfcAlignment
+    typename aggregate_of<typename Schema::IfcObjectDefinition>::ptr list_of_alignments_in_project(new aggregate_of<typename Schema::IfcObjectDefinition>());
+    list_of_alignments_in_project->push(alignment);
+    auto aggregate_alignments_with_project = new Schema::IfcRelAggregates(IfcParse::IfcGlobalId(), nullptr, std::string("Alignments in project"), boost::none, project, list_of_alignments_in_project);
+    file.addEntity(aggregate_alignments_with_project);
+
+    // Define the spatial structure of the alignment with respect to the site
+
+    // IFC 4.1.5.1 alignment is referenced in spatial structure of an IfcSpatialElement. In this case IfcSite is the highest level IfcSpatialElement
+    // https://standards.buildingsmart.org/IFC/RELEASE/IFC4_3/HTML/concepts/Object_Connectivity/Alignment_Spatial_Reference/content.html
+    // IfcSite <-> IfcRelReferencedInSpatialStructure <-> IfcAlignment
+    // This means IfcAlignment is not part of the IfcSite (it is not an aggregate component) but instead IfcAlignment is used within
+    // the IfcSite by reference. This implies an IfcAlignment can traverse many IfcSite instances within an IfcProject
+    typename Schema::IfcSpatialReferenceSelect::list::ptr list_alignments_referenced_in_site(new Schema::IfcSpatialReferenceSelect::list);
+    list_alignments_referenced_in_site->push(alignment);
+
+    // Complete the model by creating sites for the 3 bridges
+    for (int i = 1; i <= 3; i++) {
+        std::ostringstream os;
+        os << "Site of Bridge " << i;
+        auto site = file.addSite(project, nullptr);
+        site->setName(os.str());
+
+        auto rel_referenced_in_spatial_structure = new Schema::IfcRelReferencedInSpatialStructure(IfcParse::IfcGlobalId(), nullptr, boost::none, boost::none, list_alignments_referenced_in_site, site);
+        file.addEntity(rel_referenced_in_spatial_structure);
+    }
+
+    // That's it - save the model to a file
+    std::ofstream ofs("FHWA_Bridge_Geometry_Alignment_Example_Simplified.ifc");
+    ofs << file;
+}