#3616 Only consider distance orthogonal to projection vector for 2d boolean preprocessing

src/ifcgeom/kernels/opencascade/boolean_utils.cpp

@@ -683,8 +683,21 @@ bool IfcGeom::util::boolean_subtraction_2d_using_builder(const TopoDS_Shape & a_
 					BRep_Tool::Curve(e1, u21, u22)
 				);
 
+				if (!ecc.Extrema().IsParallel() && ecc.NbExtrema() == 1) {
 					// @todo: extend this to work in case of multiple extrema and curved segments.
-				const bool unbounded_intersects = (!ecc.Extrema().IsParallel() && ecc.NbExtrema() == 1 && ecc.Distance(1) < eps);
+					gp_Pnt p1, p2;
+					ecc.Points(1, p1, p2);
+
+					// #3616 Only take into account orthogonal distance between closest points on curve
+					// to see whether inside tolerance. Current DY is hardcoded. The sensible default
+					// for walls.
+					gp_Vec vec(p1, p2);
+					Standard_Real d = vec.Dot(gp::DY());
+					gp_Vec projected = d * gp::DY();
+					gp_Vec ortho_remainder = vec - projected;
+					Standard_Real ortho_distance = ortho_remainder.Magnitude();
+
+					const bool unbounded_intersects = ortho_distance < eps;
 					if (unbounded_intersects) {
 						ecc.Parameters(1, U1, U2);
 
@@ -711,6 +724,7 @@ bool IfcGeom::util::boolean_subtraction_2d_using_builder(const TopoDS_Shape & a_
 				}
 			}
 		}
+	}
 
 	// Only inner wires are considered that are directly contained in the outer wire
 	// Redundant subtractions are eliminated.