diff --git a/src/ifcgeom/IfcGeomShapes.cpp b/src/ifcgeom/IfcGeomShapes.cpp
index 82c98d5a85..e5628e863b 100644
--- a/src/ifcgeom/IfcGeomShapes.cpp
+++ b/src/ifcgeom/IfcGeomShapes.cpp
@@ -842,24 +842,32 @@ bool IfcGeom::Kernel::convert(const IfcSchema::IfcCsgSolid* l, TopoDS_Shape& sha
 
 bool IfcGeom::Kernel::convert(const IfcSchema::IfcCurveBoundedPlane* l, TopoDS_Shape& face) {
 	gp_Pln pln;
-	IfcGeom::Kernel::convert(l->BasisSurface(), pln);
+	if (!IfcGeom::Kernel::convert(l->BasisSurface(), pln)) {
+		return false;
+	}
 
 	gp_Trsf trsf;
 	trsf.SetTransformation(pln.Position(), gp::XOY());
 	
 	TopoDS_Wire outer;
-	convert_wire(l->OuterBoundary(), outer);
+	if (!convert_wire(l->OuterBoundary(), outer)) {
+		return false;
+	}
 	
-	BRepBuilderAPI_MakeFace mf (outer);
-	mf.Add(outer);
+	BRepBuilderAPI_MakeFace mf(outer);
 
+	if (!mf.IsDone() || mf.Shape().IsNull()) {
+		Logger::Error("Invalid outer boundary:", l->OuterBoundary());
+		return false;
+	}
+	
 	IfcSchema::IfcCurve::list::ptr boundaries = l->InnerBoundaries();
 
 	for (IfcSchema::IfcCurve::list::it it = boundaries->begin(); it != boundaries->end(); ++it) {
 		TopoDS_Wire inner;
-		convert_wire(*it, inner);
-		
-		mf.Add(inner);
+		if (convert_wire(*it, inner)) {
+			mf.Add(inner);
+		}
 	}
 
 	ShapeFix_Shape sfs(mf.Face());
diff --git a/src/ifcgeom_schema_agnostic/Kernel.cpp b/src/ifcgeom_schema_agnostic/Kernel.cpp
index ac77fdff7c..d85c9015ac 100644
--- a/src/ifcgeom_schema_agnostic/Kernel.cpp
+++ b/src/ifcgeom_schema_agnostic/Kernel.cpp
@@ -177,14 +177,24 @@ std::map<std::string, IfcUtil::IfcBaseEntity*> IfcGeom::Kernel::get_layers(IfcUt
 }
 
 bool IfcGeom::Kernel::is_manifold(const TopoDS_Shape& a) {
-	TopTools_IndexedDataMapOfShapeListOfShape map;
-	TopExp::MapShapesAndAncestors(a, TopAbs_EDGE, TopAbs_FACE, map);
-
-	for (int i = 1; i <= map.Extent(); ++i) {
-		if (map.FindFromIndex(i).Extent() != 2) {
-			return false;
+	if (a.ShapeType() == TopAbs_COMPOUND) {
+		TopoDS_Iterator it(a);
+		for (; it.More(); it.Next()) {
+			if (!is_manifold(it.Value())) {
+				return false;
+			}
 		}
-	}
+		return true;
+	} else {
+		TopTools_IndexedDataMapOfShapeListOfShape map;
+		TopExp::MapShapesAndAncestors(a, TopAbs_EDGE, TopAbs_FACE, map);
 
-	return true;
+		for (int i = 1; i <= map.Extent(); ++i) {
+			if (map.FindFromIndex(i).Extent() != 2) {
+				return false;
+			}
+		}
+
+		return true;
+	}
 }
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