From 0301e2fb1bb6f997da3dd330d34f60ce7d4a38cb Mon Sep 17 00:00:00 2001
From: aothms <t.krijnen@gmail.com>
Date: Wed, 2 Dec 2015 10:17:59 +0100
Subject: [PATCH] Emit an error message on extrusions with negative height or
 under model precision

---
 src/ifcgeom/IfcGeomShapes.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/ifcgeom/IfcGeomShapes.cpp b/src/ifcgeom/IfcGeomShapes.cpp
index 896863805d..1ee17e9221 100644
--- a/src/ifcgeom/IfcGeomShapes.cpp
+++ b/src/ifcgeom/IfcGeomShapes.cpp
@@ -99,10 +99,15 @@
 #include "../ifcgeom/IfcGeom.h"
 
 bool IfcGeom::Kernel::convert(const IfcSchema::IfcExtrudedAreaSolid* l, TopoDS_Shape& shape) {
+	const double height = l->Depth() * getValue(GV_LENGTH_UNIT);
+	if (height < getValue(GV_PRECISION)) {
+		Logger::Message(Logger::LOG_ERROR, "Non-positive extrusion height encountered for:", l);
+		return false;
+	}
+
 	TopoDS_Shape face;
 	if ( !convert_face(l->SweptArea(),face) ) return false;
 
-	const double height = l->Depth() * getValue(GV_LENGTH_UNIT);
 	gp_Trsf trsf;
 	IfcGeom::Kernel::convert(l->Position(),trsf);