From 564c4b7644e79d8bc6d96a8a3fe8794a3dfde875 Mon Sep 17 00:00:00 2001
From: Thomas Krijnen <t.krijnen@gmail.com>
Date: Fri, 8 Apr 2022 10:45:28 +0200
Subject: [PATCH] #2126 reverse 1st operand inner wires in 2d opening
 subtraction

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

diff --git a/src/ifcgeom/IfcGeomFunctions.cpp b/src/ifcgeom/IfcGeomFunctions.cpp
index 88e2bf132a..f0e233dde6 100644
--- a/src/ifcgeom/IfcGeomFunctions.cpp
+++ b/src/ifcgeom/IfcGeomFunctions.cpp
@@ -4599,6 +4599,13 @@ namespace {
 
 				if (outer_wire.IsNull() || !it2.Value().IsSame(outer_wire)) {
 					wires.push_back(TopoDS::Wire(it2.Value()));
+
+					if (shape_index == 0 && num_wires > 0) {
+						// An inner wire on the first operand face: reverse, because
+						// MakeFace expects inner boundaries to be added as bounded
+						// areas.
+						wires.back().Reverse();
+					}
 				}
 			}