diff --git a/src/ifcparse/IfcGeom.cpp b/src/ifcparse/IfcGeom.cpp
index 2302af8677..19097df209 100644
--- a/src/ifcparse/IfcGeom.cpp
+++ b/src/ifcparse/IfcGeom.cpp
@@ -45,6 +45,7 @@
 #include <TColgp_Array1OfPnt2d.hxx>
 #include <TColStd_Array1OfReal.hxx>
 #include <TColStd_Array1OfInteger.hxx>
+#include <Geom_Line.hxx>
 #include <Geom_Circle.hxx>
 #include <Geom_Ellipse.hxx>
 #include <Geom_TrimmedCurve.hxx>
@@ -256,6 +257,11 @@ bool IfcGeom::convert(IfcSchema::Direction* IfcDirection, gp_Vec& v) {
 		v = gp_Vec(IfcDirection->X(),IfcDirection->Y(),0.0f);
 	return true;
 }
+bool IfcGeom::convert(IfcSchema::Vector* IfcVector, gp_Vec& v) {
+	IfcGeom::convert((IfcSchema::Direction*)IfcVector->Orientation().get(),v);
+	v.Scale(IfcVector->Magnitude());
+	return true;
+}
 bool IfcGeom::convert(IfcSchema::ArbitraryClosedProfileDef* IfcArbitraryClosedProfileDef, TopoDS_Wire& wire) {
 	return IfcGeom::convert_wire(IfcArbitraryClosedProfileDef->Polyline(),wire);
 }
@@ -411,7 +417,10 @@ bool IfcGeom::convert(IfcSchema::CompositeCurve* IfcCompositeCurve, class TopoDS
 	for( IfcParse::Entities::it it = segments->begin(); it != segments->end(); ++ it ) {
 		IfcSchema::CompositeCurveSegment* segment = (IfcSchema::CompositeCurveSegment*)(*it).get();
 		TopoDS_Wire wire2;
-		if ( ! IfcGeom::convert_wire(segment->ParentCurve(),wire2) ) continue;
+		if ( ! IfcGeom::convert_wire(segment->ParentCurve(),wire2) ) {
+			std::cout << "[Warning] Failed to convert:" << std::endl << segment->ParentCurve()->toString() << std::endl;
+			continue;	
+		}
 		ShapeFix_ShapeTolerance FTol;
 		FTol.SetTolerance(wire2, 0.01, TopAbs_WIRE);
 		w.Add(wire2);
@@ -425,26 +434,45 @@ bool IfcGeom::convert(IfcSchema::CompositeCurve* IfcCompositeCurve, class TopoDS
 }
 bool IfcGeom::convert(IfcSchema::TrimmedCurve* IfcTrimmedCurve, class TopoDS_Wire& wire) {
 	IfcEntity basis = IfcTrimmedCurve->BasisCurve();
-	IfcEntity trim1 = *IfcTrimmedCurve->Trim1()->begin();
-	IfcEntity trim2 = *IfcTrimmedCurve->Trim2()->begin();
+	bool isConic = basis->dt == IfcSchema::Enum::IfcCircle || basis->dt == IfcSchema::Enum::IfcEllipse;
+	float parameterFactor = isConic ? Ifc::PlaneAngleUnit : Ifc::LengthUnit;
 	Handle(Geom_Curve) curve;
 	if ( ! IfcGeom::convert_curve(basis,curve) ) return false;
-	if ( trim1->dt != trim2->dt ) return false;
+	bool cartesian = IfcTrimmedCurve->MasterRepresentation() == "CARTESIAN";
+	IfcEntities trims1 = IfcTrimmedCurve->Trim1();
+	IfcEntities trims2 = IfcTrimmedCurve->Trim2();
+	bool trimmed1 = false;
+	bool trimmed2 = false;
+	float flt1;
+	gp_Pnt pnt1;
 	BRepBuilderAPI_MakeWire w;
-	if ( trim1->dt == IfcSchema::Enum::IfcParameterValue ) {
-		const float p1 = ((IfcSchema::ParameterValue*)trim1.get())->Value() * Ifc::PlaneAngleUnit;
-		const float p2 = ((IfcSchema::ParameterValue*)trim2.get())->Value() * Ifc::PlaneAngleUnit;
-		BRepBuilderAPI_MakeEdge e (curve,p1,p2);
-		w.Add(e.Edge());
-	} else if ( trim1->dt == IfcSchema::Enum::IfcCartesianPoint ) {
-		gp_Pnt v1,v2;
-		IfcGeom::convert((IfcSchema::CartesianPoint*)trim1.get(),v1);
-		IfcGeom::convert((IfcSchema::CartesianPoint*)trim2.get(),v2);
-		BRepBuilderAPI_MakeEdge e (curve,v1,v2);
-		w.Add(e.Edge());
+	for ( IfcParse::Entities::it it = trims1->begin(); it != trims1->end(); it ++ ) {
+		const IfcEntity i = *it;
+		if ( i->dt == IfcSchema::Enum::IfcCartesianPoint && cartesian ) {
+			IfcGeom::convert( (IfcSchema::CartesianPoint*) i.get(), pnt1 );
+			trimmed1 = true;
+		} else if ( i->dt == IfcSchema::Enum::IfcParameterValue ) {
+			flt1 = ((IfcSchema::ParameterValue*)i.get())->Value() * parameterFactor;
+			trimmed1 = true;
+		}
 	}
-	wire = w.Wire();
-	return true;
+	for ( IfcParse::Entities::it it = trims2->begin(); it != trims2->end(); it ++ ) {
+		const IfcEntity i = *it;
+		if ( i->dt == IfcSchema::Enum::IfcCartesianPoint && cartesian && trimmed1 ) {
+			gp_Pnt pnt2;
+			IfcGeom::convert( (IfcSchema::CartesianPoint*) i.get(), pnt2 );
+			BRepBuilderAPI_MakeEdge e (curve,pnt1,pnt2);
+			w.Add(e.Edge());			
+			trimmed2 = true;
+		} else if ( i->dt == IfcSchema::Enum::IfcParameterValue && trimmed1 ) {
+			float flt2 = ((IfcSchema::ParameterValue*)i.get())->Value() * parameterFactor;
+			BRepBuilderAPI_MakeEdge e (curve,flt1,flt2);
+			w.Add(e.Edge());
+			trimmed2 = true;
+		}
+	}
+	if ( trimmed2 ) wire = w.Wire();
+	return trimmed2;
 }
 bool IfcGeom::convert(IfcSchema::Circle* IfcCircle, Handle(Geom_Curve)& curve) {
 	const float r = IfcCircle->Radius() * Ifc::LengthUnit;
@@ -468,6 +496,13 @@ bool IfcGeom::convert(IfcSchema::Ellipse* IfcEllipse, Handle(Geom_Curve)& curve)
 	curve = new Geom_Ellipse(ax, x, y);
 	return true;
 }
+bool IfcGeom::convert(IfcSchema::Line* IfcLine, Handle(Geom_Curve)& curve) {
+	gp_Pnt pnt;gp_Vec vec;
+	IfcGeom::convert((IfcSchema::CartesianPoint*)IfcLine->Pnt().get(),pnt);
+	IfcGeom::convert((IfcSchema::Vector*)IfcLine->Dir().get(),vec);	
+	curve = new Geom_Line(pnt,vec);
+	return true;
+}
 bool IfcGeom::convert(IfcSchema::Polyline* IfcPolyline, TopoDS_Wire& result) {
 	IfcEntities points = IfcPolyline->Points();
 
@@ -493,36 +528,47 @@ bool IfcGeom::convert(IfcSchema::Polyloop* IfcPolyloop, TopoDS_Wire& result) {
 	return IfcGeom::convert((IfcSchema::Polyline*)IfcPolyloop,result);
 }
 bool IfcGeom::convert(IfcSchema::Axis2Placement3D* IfcAxis2Placement3D, gp_Trsf& trsf) {
-	gp_Pnt o;gp_Vec x = gp_Vec(1,0,0);gp_Vec z = gp_Vec(0,0,1);
+	gp_Pnt o;gp_Vec axis = gp_Vec(0,0,1);gp_Vec refDirection; bool hasRef = false;
 
 	IfcGeom::convert((IfcSchema::CartesianPoint*) IfcAxis2Placement3D->Origin().get(),o);
 	try {
-		IfcGeom::convert((IfcSchema::Direction*) IfcAxis2Placement3D->Dir1().get(),z);
-		IfcGeom::convert((IfcSchema::Direction*) IfcAxis2Placement3D->Dir2().get(),x);
+		IfcGeom::convert((IfcSchema::Direction*) IfcAxis2Placement3D->Axis().get(),axis);
+		IfcGeom::convert((IfcSchema::Direction*) IfcAxis2Placement3D->RefDirection().get(),refDirection);
+		hasRef = true;
 	} catch( IfcParse::IfcException& ) {}
 
-	gp_Ax3 axis(o,z,x);
-	gp_Ax3 def(gp_Pnt(),gp_Dir(0,0,1),gp_Dir(1,0,0));
-	trsf.SetTransformation(axis,def);
+	gp_Ax3 ax3;
+	if ( hasRef ) ax3 = gp_Ax3(o,axis,refDirection);
+	else ax3 = gp_Ax3(o,axis);
+
+	trsf.SetTransformation(ax3, gp_Ax3(gp_Pnt(),gp_Dir(0,0,1),gp_Dir(1,0,0)));
 	return true;
 }
 bool IfcGeom::convert(IfcSchema::Plane* IfcPlane, gp_Pln& plane) {
 	IfcSchema::Axis2Placement3D* IfcAxis2Placement3D = (IfcSchema::Axis2Placement3D*) IfcPlane->Placement().get();
-	gp_Pnt o;gp_Vec x;gp_Vec z;
+	gp_Pnt o;gp_Vec axis = gp_Vec(0,0,1);gp_Vec refDirection; bool hasRef = false;
 
 	IfcGeom::convert((IfcSchema::CartesianPoint*) IfcAxis2Placement3D->Origin().get(),o);
-	IfcGeom::convert((IfcSchema::Direction*) IfcAxis2Placement3D->Dir1().get(),z);
-	IfcGeom::convert((IfcSchema::Direction*) IfcAxis2Placement3D->Dir2().get(),x);
+	try {
+		IfcGeom::convert((IfcSchema::Direction*) IfcAxis2Placement3D->Axis().get(),axis);
+		IfcGeom::convert((IfcSchema::Direction*) IfcAxis2Placement3D->RefDirection().get(),refDirection);
+		hasRef = true;
+	} catch( IfcParse::IfcException& ) {}
 
-	gp_Ax3 axis(o,z,x);
-	plane = gp_Pln(axis);
+	gp_Ax3 ax3;
+	if ( hasRef ) ax3 = gp_Ax3(o,axis,refDirection);
+	else ax3 = gp_Ax3(o,axis);
+
+	plane = gp_Pln(ax3);
 	return true;
 }
 bool IfcGeom::convert(IfcSchema::Axis2Placement2D* IfcAxis2Placement2D, gp_Trsf2d& trsf) {
-	gp_Pnt P; gp_Vec V;
+	gp_Pnt P; gp_Vec V (1,0,0);
 
 	IfcGeom::convert((IfcSchema::CartesianPoint*) IfcAxis2Placement2D->Origin().get(),P);
-	IfcGeom::convert((IfcSchema::Direction*) IfcAxis2Placement2D->Dir1().get(),V);
+	try {
+		IfcGeom::convert((IfcSchema::Direction*) IfcAxis2Placement2D->Axis().get(),V);
+	} catch( IfcParse::IfcException& ) {}
 
 	gp_Ax2d axis(gp_Pnt2d(P.X(),P.Y()),gp_Vec2d(V.X(),V.Y()));
 	trsf.SetTransformation(axis,gp_Ax2d());
diff --git a/src/ifcparse/IfcGeomObjects.cpp b/src/ifcparse/IfcGeomObjects.cpp
index be6544761b..5b1710b704 100644
--- a/src/ifcparse/IfcGeomObjects.cpp
+++ b/src/ifcparse/IfcGeomObjects.cpp
@@ -193,7 +193,7 @@ IfcGeomObjects::IfcGeomObject* _get() {
 				const IfcEntity ifcshape = *it;
 				if ( ifcshape->dt == IfcSchema::Enum::IfcMappedItem ) continue;
 				TopoDS_Shape ss;
-				if ( IfcGeom::convert_shape(ifcshape,ss) ) {
+				if ( IfcGeom::convert_shape(ifcshape,ss) && ! ss.IsNull() ) {
 					builder.Add(shapes,ss);
 					hasShapes = true;
 #ifdef _DEBUG
diff --git a/src/ifcparse/IfcParse.cpp b/src/ifcparse/IfcParse.cpp
index 5c61081bc7..61a4177edc 100644
--- a/src/ifcparse/IfcParse.cpp
+++ b/src/ifcparse/IfcParse.cpp
@@ -142,7 +142,13 @@ bool ArgumentList::b() const { return _arg->b(); }
 int ArgumentList::i() const { return _arg->i(); }
 std::string ArgumentList::s() const { return _arg->s(); }
 int ArgumentList::count() const { return _arg ? 1 : _args.size(); }
-ArgumentList* ArgumentList::arg(int i) const { return _args[i]; }
+ArgumentList* ArgumentList::arg(int i) const { 
+	if ( i >= count() ) {
+		throw IfcException();
+	} else {
+		return _args[i]; 
+	}
+}
 
 EntityPtr ArgumentList::ref() const {
 	if ( _arg->type == Argument::IDENTIFIER ) {
@@ -410,8 +416,10 @@ bool Ifc::Init(const std::string& fn) {
 		if ( unit->dt == IfcSchema::Enum::IfcConversionBasedUnit ) {
 			IfcSchema::ConversionBasedUnit* IfcConversionBasedUnit = (IfcSchema::ConversionBasedUnit*)(*it).get();
 			IfcSchema::MeasureWithUnit* IfcMeasureWithUnit = (IfcSchema::MeasureWithUnit*)IfcConversionBasedUnit->ConversionFactor().get();
-			unit = IfcMeasureWithUnit->Unit();
-			value = IfcMeasureWithUnit->Value()->arg(0)->f();
+			try {
+				unit = IfcMeasureWithUnit->Unit();
+				value = IfcMeasureWithUnit->Value()->arg(0)->f();
+			} catch (... ) {}
 		}
 		if ( unit->dt == IfcSchema::Enum::IfcSIUnit ) {
 			IfcSchema::SIUnit* IfcSIUnit = (IfcSchema::SIUnit*)(*it).get();
diff --git a/src/ifcparse/IfcSchema.h b/src/ifcparse/IfcSchema.h
index ad90603332..8b7f83c444 100644
--- a/src/ifcparse/IfcSchema.h
+++ b/src/ifcparse/IfcSchema.h
@@ -164,6 +164,11 @@ IFC_REF(Circle,Placement,0)
 IFC_FLT(Circle,Radius,1)
 IFC_END_CLASS
 
+IFC_CURVE_CLASS(Line)
+IFC_REF(Line,Pnt,0)
+IFC_REF(Line,Dir,1)
+IFC_END_CLASS
+
 IFC_CURVE_CLASS(Ellipse)
 IFC_REF(Ellipse,Placement,0)
 IFC_FLT(Ellipse,Axis1,1)
@@ -182,15 +187,20 @@ IFC_FLT_SUB(Direction,Y,0,1)
 IFC_FLT_SUB(Direction,Z,0,2)
 IFC_END_CLASS
 
+IFC_CLASS(Vector,gp_Vec)
+IFC_REF(Vector,Orientation,0)
+IFC_FLT(Vector,Magnitude,1)
+IFC_END_CLASS
+
 IFC_CLASS(Axis2Placement3D,gp_Trsf)
 IFC_REF(Axis2Placement3D,Origin,0)
-IFC_REF(Axis2Placement3D,Dir1,1)
-IFC_REF(Axis2Placement3D,Dir2,2)
+IFC_REF(Axis2Placement3D,Axis,1)
+IFC_REF(Axis2Placement3D,RefDirection,2)
 IFC_END_CLASS
 
 IFC_CLASS(Axis2Placement2D,gp_Trsf2d)
 IFC_REF(Axis2Placement2D,Origin,0)
-IFC_REF(Axis2Placement2D,Dir1,1)
+IFC_REF(Axis2Placement2D,Axis,1)
 IFC_END_CLASS
 
 IFC_CLASS(LocalPlacement,gp_Trsf)