From 9de9645229299af60009f31311d6527ed6102e5c Mon Sep 17 00:00:00 2001
From: Thomas Krijnen <t.krijnen@gmail.com>
Date: Fri, 13 Jan 2023 13:56:38 +0100
Subject: [PATCH] #2665 increase halfspace tolerance comparison

---
 src/ifcgeom/IfcBooleanResult.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/ifcgeom/IfcBooleanResult.cpp b/src/ifcgeom/IfcBooleanResult.cpp
index 76cb4f961a..94eccfeec0 100644
--- a/src/ifcgeom/IfcBooleanResult.cpp
+++ b/src/ifcgeom/IfcBooleanResult.cpp
@@ -136,7 +136,9 @@ bool IfcGeom::Kernel::convert(const IfcSchema::IfcBooleanResult* l, TopoDS_Shape
 			TopoDS_Shape temp;
 			double d;
 			if (util::fit_halfspace(s1, s2, temp, d, getValue(GV_PRECISION))) {
-				if (d < getValue(GV_PRECISION)) {
+				// #2665 we also set a precision-independent treshold, because in the boolean op routine
+				// the working fuzziness might still be increased.
+				if (d < getValue(GV_PRECISION) * 20. || d < 0.00002) {
 					Logger::Message(Logger::LOG_WARNING, "Halfspace subtraction yields unchanged volume:", l);
 					continue;
 				} else {