Implements IfcOffsetCurveByDistance mapping

src/ifcgeom/mapping/IfcOffsetCurveByDistance.cpp

@@ -0,0 +1,162 @@
+/********************************************************************************
+ *                                                                              *
+ * 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 copz of the Lesser GNU General Public License     *
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.         *
+ *                                                                              *
+ ********************************************************************************/
+
+#include "mapping.h"
+#define mapping POSTFIX_SCHEMA(mapping)
+using namespace ifcopenshell::geometry;
+
+// ifc4x1
+//#define SCHEMA_IfcOffsetCurveByDistances_HAS_OffsetValues
+//#define SCHEMA_IfcOffsetCurveByDistances_HAS_Tag
+//#define SCHEMA_IfcOffsetCurveByDistances_Tag_IS_OPTIONAL
+
+#ifdef SCHEMA_HAS_IfcOffsetCurveByDistances
+
+taxonomy::ptr mapping::map_impl(const IfcSchema::IfcOffsetCurveByDistances* inst) {
+    auto offset_values = inst->OffsetValues();
+    if (offset_values->size() == 0) {
+        Logger::Error("IfcOffsetCurveByDistances must have at least one offset value");
+    }
+
+    auto basis_curve = inst->BasisCurve();
+
+    auto first_offset_value = *(offset_values->begin());
+
+    // todo@ rb - basis_curve might not be piecewise - other valid types are IfcOffsetCurveByDistances, IfcPolyline and IfcIndexedPolyCurve
+    // Is there a more generic type that can be evaluated at "u"?
+   auto basis = taxonomy::cast<taxonomy::piecewise_function>(map(basis_curve));
+   double basis_curve_length = 0;
+   for (auto& s : basis->spans) {
+       basis_curve_length += s.first;
+   }
+
+    auto offsets = taxonomy::make<taxonomy::piecewise_function>();
+
+#if defined SCHEMA_HAS_IfcDistanceExpression
+   double first_distance = first_offset_value->DistanceAlong();
+#else
+   double first_distance = *first_offset_value->DistanceAlong()->as<IfcSchema::IfcLengthMeasure>();
+#endif
+
+   if (first_distance < 0.0) {
+        Logger::Warning("IfcOffsetCurveByDistance first offset value is before the start of the curve.");
+   }
+
+   if(0.0 < first_distance)
+   {
+      // First offset is defined after the start of the curve so the lateral and vertical offsets
+		// implicitly continue with the same value towards the start of the basis curve
+        double py = first_offset_value->OffsetLateral().get_value_or(0.0);
+        double pz = first_offset_value->OffsetVertical().get_value_or(0.0);
+        py *= length_unit_;
+        pz *= length_unit_;
+        
+        auto fn = [py, pz](double u) -> Eigen::Matrix4d { 
+           Eigen::Matrix4d m = Eigen::Matrix4d::Identity(); 
+           m.col(3)(1) = py; 
+           m.col(3)(2) = pz; 
+           return m; };
+        offsets->spans.push_back({first_distance, fn});
+	}
+
+    auto iter = offset_values->begin();
+    auto next = std::next(iter);
+    auto prev = std::prev(next);
+    auto end = offset_values->end();
+    for (; next != end; prev++, next++) {
+#if defined SCHEMA_HAS_IfcPointByDistanceExpression
+        if ((*prev)->BasisCurve() != basis_curve || (*next)->BasisCurve() != basis_curve) {
+            Logger::Error("All offsets from a IfcOffsetCurveByDistances must refer to the same BasisCurve");
+        }
+#endif
+
+#if defined SCHEMA_HAS_IfcDistanceExpression
+        double dn = (*next)->DistanceAlong();
+        double dp = (*prev)->DistanceAlong();
+#else
+        double dn = *(*next)->DistanceAlong()->as<IfcSchema::IfcLengthMeasure>();
+        double dp = *(*prev)->DistanceAlong()->as<IfcSchema::IfcLengthMeasure>();
+#endif
+        if ((dp < 0.0 || basis_curve_length < dp) 
+             or 
+            (dn < 0.0 || basis_curve_length < dn))
+        {
+            Logger::Warning("IfcOffsetCurveByDistance offset value is out of bounds.");
+            continue;
+        }
+
+        double l = (dn - dp)*length_unit_;
+        double yn = (*next)->OffsetLateral().get_value_or(0.0) * length_unit_;
+        double yp = (*prev)->OffsetLateral().get_value_or(0.0) * length_unit_;
+        double zn = (*next)->OffsetVertical().get_value_or(0.0) * length_unit_;
+        double zp = (*prev)->OffsetVertical().get_value_or(0.0) * length_unit_;
+       
+        auto fn = [yp, yn, zp, zn, l](double u) -> Eigen::Matrix4d {
+            Eigen::Matrix4d m = Eigen::Matrix4d::Identity();
+            m.col(3)(1) = (l == 0.0 ? yp : (yp + (yn - yp) * u / l));
+            m.col(3)(2) = (l == 0.0 ? zp : (zp + (zn - zp) * u / l));
+            return m;
+        };
+		  offsets->spans.push_back({l, fn});
+    }
+
+	 // at this point, next == end and prev == end-1
+    #if defined SCHEMA_HAS_IfcDistanceExpression
+    double last_distance = (*prev)->DistanceAlong() * length_unit_;
+    #else
+    double last_distance = *(*prev)->DistanceAlong()->as<IfcSchema::IfcLengthMeasure>() * length_unit_;
+    #endif
+    
+    if (basis_curve_length < last_distance) {
+          Logger::Warning("IfcOffsetCurveByDistance last offset value is after the end of the curve.");
+    }
+
+    if (last_distance < basis_curve_length) {
+         // Last offset is defined before the end of the curve so the lateral and vertical offsets
+         // implicitly continue with the same value towards the end of the basis curve
+         double py = (*prev)->OffsetLateral().get_value_or(0.0);
+         double pz = (*prev)->OffsetVertical().get_value_or(0.0);
+         py *= length_unit_;
+         pz *= length_unit_;
+         double l = basis_curve_length - last_distance;
+         auto fn = [py, pz](double u) -> Eigen::Matrix4d { 
+            Eigen::Matrix4d m = Eigen::Matrix4d::Identity(); 
+            m.col(3)(1) = py; 
+            m.col(3)(2) = pz; 
+            return m; };
+
+         offsets->spans.push_back({l, fn});
+    }
+
+	auto composition = [basis, offsets](double u)->Eigen::Matrix4d {
+		auto p = basis->evaluate(u);
+		auto offset = offsets->evaluate(u);
+      Eigen::Matrix4d m = p * offset;
+      return m;
+	};
+
+   // current implementation assumes that offsets is equal to the full length of basis curve
+   // this may change depending on decisions in the bSI-IF
+	auto pwf = taxonomy::make<taxonomy::piecewise_function>();
+	pwf->spans.emplace_back( basis_curve_length, composition );
+	pwf->instance = inst;
+	return pwf;
+}
+
+#endif

src/ifcgeom/mapping/mapping.i

@@ -120,6 +120,9 @@ BIND(IfcSegmentedReferenceCurve);
 BIND(IfcGradientCurve);
 #endif
 BIND(IfcCompositeCurve);
+#ifdef SCHEMA_HAS_IfcOffsetCurveByDistances
+BIND(IfcOffsetCurveByDistances)
+#endif
 BIND(IfcTrimmedCurve);
 BIND(IfcArbitraryOpenProfileDef);
 #ifdef SCHEMA_HAS_IfcIndexedPolyCurve