From f5979be4d570ff99b77024cf76674dc7f55c669e Mon Sep 17 00:00:00 2001
From: Thomas Krijnen <t.krijnen@gmail.com>
Date: Tue, 18 Jun 2024 13:09:22 +0200
Subject: [PATCH] Keep old behaviour of subtractions, when failed use first
 operand #4832

---
 src/ifcgeom/kernels/opencascade/boolean_result.cpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/ifcgeom/kernels/opencascade/boolean_result.cpp b/src/ifcgeom/kernels/opencascade/boolean_result.cpp
index 1deaf49cf7..83e4253102 100644
--- a/src/ifcgeom/kernels/opencascade/boolean_result.cpp
+++ b/src/ifcgeom/kernels/opencascade/boolean_result.cpp
@@ -182,12 +182,16 @@ bool OpenCascadeKernel::convert_impl(const taxonomy::boolean_result::ptr br, Con
 		valid_result = util::boolean_operation(bst, a, b, op_to_occt(br->operation), r);
 	}
 
+	if (valid_result) {
+		std::swap(r, a);
+	}
+
 	results.emplace_back(IfcGeom::ConversionResult(
 		(int) br->instance->data().id(),
 		br->matrix,
-		new OpenCascadeShape(r),
+		new OpenCascadeShape(a),
 		br->surface_style ? br->surface_style : first_item_style
 	));
 
-	return valid_result;
+	return true;
 }