Small changes to curve segment handling for purpose of wrapper

src/ifcgeom/mapping/IfcCompositeCurve.cpp

@@ -88,9 +88,11 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcCompositeCurve* inst) {
 		aggregate_of_instance::ptr profile = inst->data().getInverse(&IfcSchema::IfcProfileDef::Class(), -1);
 		const bool force_close = profile && profile->size() > 0;
 		loop->closed = force_close;
+		loop->instance = inst;
 		return loop;
 	}
 	else {
+		pwf->instance = inst;
 		return pwf;
 	}
 }

src/ifcgeom/mapping/IfcCurveSegment.cpp

@@ -455,6 +455,7 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcCurveSegment* inst) {
 	// @todo it might be suboptimal that we no longer have the spans now
 	auto pwf = taxonomy::make<taxonomy::piecewise_function>();
 	pwf->spans.push_back({ length, fn_transformed });
+	pwf->instance = inst;
 	return pwf;
 
 	/*

src/ifcgeom/mapping/IfcGradientCurve.cpp

@@ -70,6 +70,7 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcGradientCurve* inst) {
 
 	auto pwf = taxonomy::make<taxonomy::piecewise_function>();
 	pwf->spans.emplace_back( min_length, composition );
+	pwf->instance = inst;
 	return pwf;
 }