diff --git a/src/ifcgeom/mapping/IfcOpenCrossProfileDef.cpp b/src/ifcgeom/mapping/IfcOpenCrossProfileDef.cpp
new file mode 100644
index 0000000000..d3083a23e7
--- /dev/null
+++ b/src/ifcgeom/mapping/IfcOpenCrossProfileDef.cpp
@@ -0,0 +1,94 @@
+/********************************************************************************
+ *                                                                              *
+ * 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/>.         *
+ *                                                                              *
+ ********************************************************************************/
+
+#include "mapping.h"
+#define mapping POSTFIX_SCHEMA(mapping)
+using namespace ifcopenshell::geometry;
+
+#include "../../ifcgeom/profile_helper.h"
+#include "../../ifcgeom/infra_sweep_helper.h"
+
+#include <boost/math/constants/constants.hpp>
+const double PI = boost::math::constants::pi<double>();
+
+#ifdef SCHEMA_HAS_IfcOpenCrossProfileDef
+
+
+taxonomy::ptr mapping::map_impl(const IfcSchema::IfcOpenCrossProfileDef* inst) {
+    if (inst->ProfileType() != IfcSchema::IfcProfileTypeEnum::IfcProfileType_CURVE) {
+        Logger::Warning("Expected IfcOpenCrossProfileDef.ProfileType to be CURVE", inst);
+        return nullptr;
+    }
+
+    std::vector<taxonomy::point3::ptr> points;
+    taxonomy::point3::ptr start;
+    if (inst->OffsetPoint()) {
+       start = taxonomy::cast<taxonomy::point3>(map(inst->OffsetPoint()));
+    } else {
+        start = taxonomy::make<taxonomy::point3>(0., 0., 0.);
+    }
+    points.push_back(start);
+
+    boost::optional<std::vector<std::string>> tags = inst->Tags();
+    boost::optional<std::string> tag = boost::none;
+    if (tags.has_value() && !tags.get().empty()) {
+        tag = tags.get()[0];
+    }
+    start->tag = tag;
+
+    auto widths = inst->Widths();
+    auto angles = inst->Slopes(); // these are actually angles, but the attribute is called Slopes
+
+	if (widths.size() != angles.size()) {
+        Logger::Warning("Expected Widths and Slopes to be equal length, but got " + std::to_string(widths.size()) + " and " + std::to_string(angles.size()) + " respectively", inst);
+        return nullptr;
+    }
+
+   auto horizontal_widths = inst->HorizontalWidths();
+
+    double x = start->ccomponents().x();
+    double y = start->ccomponents().y();
+    double z = start->ccomponents().z();
+    for (size_t i = 0; i < widths.size(); ++i) {
+        double w = widths[i] * length_unit_;
+        double a = PI - angles[i] * angle_unit_;
+        double dx = (horizontal_widths ? w : w * std::cos(a));
+        double dy = (horizontal_widths ? w * std::tan(a) : w * std::sin(a));
+        double dz = 0.;
+        x -= dx; // subtract because X is positive to the left
+        y += dy;
+        z += dz;
+
+        if (tags.has_value() && !tags.get().empty()) {
+            tag = tags.get()[i+1];
+        }
+
+        points.push_back(taxonomy::make<taxonomy::point3>(x, y, z, tag));
+    }
+
+    auto mapped = polygon_from_points(points);
+    if (mapped->kind() == taxonomy::LOOP) {
+        auto r = taxonomy::loop::ptr((taxonomy::loop*)mapped->clone_());
+        r->closed = false;
+        return r;
+    }
+    return mapped;
+}
+
+#endif
diff --git a/src/ifcgeom/mapping/mapping.i b/src/ifcgeom/mapping/mapping.i
index adc2e3c10b..c67d0f7f4a 100644
--- a/src/ifcgeom/mapping/mapping.i
+++ b/src/ifcgeom/mapping/mapping.i
@@ -135,6 +135,9 @@ BIND(IfcFixedReferenceSweptAreaSolid)
 #ifdef SCHEMA_HAS_IfcSectionedSolidHorizontal
 BIND(IfcSectionedSolidHorizontal)
 #endif
+#ifdef SCHEMA_HAS_IfcOpenCrossProfileDef
+BIND(IfcOpenCrossProfileDef)
+#endif
 #ifdef SCHEMA_HAS_IfcSectionedSurface
 BIND(IfcSectionedSurface)
 #endif
diff --git a/src/serializers/WavefrontObjSerializer.cpp b/src/serializers/WavefrontObjSerializer.cpp
index 300fceeb88..f29612a65e 100644
--- a/src/serializers/WavefrontObjSerializer.cpp
+++ b/src/serializers/WavefrontObjSerializer.cpp
@@ -93,7 +93,9 @@ void WaveFrontOBJSerializer::write(const IfcGeom::TriangulationElement* o)
 
     const IfcGeom::Representation::Triangulation& mesh = o->geometry();
 
-	const int vcount = (int)mesh.verts().size() / 3;
+	size_t vcount = mesh.verts().size() / 3;
+    size_t ncount = mesh.normals().size() / 3;
+
 	for (auto it = mesh.verts().begin(); it != mesh.verts().end();) {
         const double x = *(it++);
         const double y = *(it++);
@@ -139,22 +141,25 @@ void WaveFrontOBJSerializer::write(const IfcGeom::TriangulationElement* o)
 			previous_material_id = material_id;
 		}
 
-		const int v1 = *(it++)+vcount_total;
-		const int v2 = *(it++)+vcount_total;
-		const int v3 = *(it++)+vcount_total;
+		const int v1 = *(it++) + vcount_total;
+		const int v2 = *(it++) + vcount_total;
+		const int v3 = *(it++) + vcount_total;
 
-		if (has_normals && has_uvs) {
-			obj_stream.stream << "f " << v1 << "/" << v1 << "/" << v1 << " "
-				<< v2 << "/" << v2 << "/" << v2 << " "
-				<< v3 << "/" << v3 << "/" << v3 << "\n";
+		const int n1 = v1 - vcount_total + ncount_total;
+        const int n2 = v2 - vcount_total + ncount_total;
+        const int n3 = v3 - vcount_total + ncount_total;
+
+        if (has_normals && has_uvs) {
+			obj_stream.stream << "f " << v1 << "/" << n1 << "/" << n1 << " "
+				<< v2 << "/" << n2 << "/" << n2 << " "
+				<< v3 << "/" << n3 << "/" << n3 << "\n";
 		} else if (has_normals) {
-			obj_stream.stream << "f " << v1 << "//" << v1 << " "
-				<< v2 << "//" << v2 << " "
-				<< v3 << "//" << v3 << "\n";
+            obj_stream.stream << "f " << v1 << "//" << n1 << " "
+				<< v2 << "//" << n2 << " "
+				<< v3 << "//" << n3 << "\n";
 		} else {
 			obj_stream.stream << "f " << v1 << " " << v2 << " " << v3 << "\n";
 		}
-
 	}
 
 	std::set<int> faces_set (mesh.faces().begin(), mesh.faces().end());
@@ -189,4 +194,5 @@ void WaveFrontOBJSerializer::write(const IfcGeom::TriangulationElement* o)
 	}
 
 	vcount_total += vcount;
+    ncount_total += ncount;
 }
diff --git a/src/serializers/WavefrontObjSerializer.h b/src/serializers/WavefrontObjSerializer.h
index 4085dfa376..d3ea41f69e 100644
--- a/src/serializers/WavefrontObjSerializer.h
+++ b/src/serializers/WavefrontObjSerializer.h
@@ -32,7 +32,7 @@ class SERIALIZERS_API WaveFrontOBJSerializer : public WriteOnlyGeometrySerialize
 private:
 	stream_or_filename obj_stream;
 	stream_or_filename mtl_stream;
-	unsigned int vcount_total;
+	size_t vcount_total, ncount_total;
 	std::set<std::string> materials;
 public:
 	WaveFrontOBJSerializer(const stream_or_filename& obj_filename, const stream_or_filename& mtl_filename, const ifcopenshell::geometry::Settings& geometry_settings, const ifcopenshell::geometry::SerializerSettings& settings);