From 8c0c216a1d7af37de3b15992243649be6f59413a Mon Sep 17 00:00:00 2001
From: Thomas Krijnen <t.krijnen@gmail.com>
Date: Sat, 8 Dec 2018 10:37:54 +0100
Subject: [PATCH 1/2] Check boolean result manifoldness for shells
 individually. Fixes #516.

---
 src/ifcgeom/IfcGeomFunctions.cpp | 26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/src/ifcgeom/IfcGeomFunctions.cpp b/src/ifcgeom/IfcGeomFunctions.cpp
index 7ae87d9954..53013da932 100644
--- a/src/ifcgeom/IfcGeomFunctions.cpp
+++ b/src/ifcgeom/IfcGeomFunctions.cpp
@@ -235,16 +235,26 @@ namespace {
 	}
 
 	bool 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;
+		}
 	}
 
 	bool is_manifold(const TopTools_ListOfShape& l) {

From f849434f24e41e8a5e7d280687cfe8cae9b3208c Mon Sep 17 00:00:00 2001
From: Thomas Krijnen <t.krijnen@gmail.com>
Date: Sun, 9 Dec 2018 11:59:49 +0100
Subject: [PATCH 2/2] More defensive IfcCurveBoundedPlane processing

---
 src/ifcgeom/IfcGeomShapes.cpp | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/src/ifcgeom/IfcGeomShapes.cpp b/src/ifcgeom/IfcGeomShapes.cpp
index 81a8af14ca..17acda26e7 100644
--- a/src/ifcgeom/IfcGeomShapes.cpp
+++ b/src/ifcgeom/IfcGeomShapes.cpp
@@ -832,24 +832,32 @@ 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()->entity);
+		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());