From 8583d0963fd8a6205ebc9d7f0d0de1e008a15cdb Mon Sep 17 00:00:00 2001 From: Thomas Krijnen Date: Thu, 4 Jun 2026 21:38:11 +0200 Subject: [PATCH] Make faceset duplicate loop detection respect inner/outer #8140 --- src/ifcgeom/kernels/opencascade/faceset_helper.cpp | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/src/ifcgeom/kernels/opencascade/faceset_helper.cpp b/src/ifcgeom/kernels/opencascade/faceset_helper.cpp index 2fd74cdf2d..54d4bfb8d7 100644 --- a/src/ifcgeom/kernels/opencascade/faceset_helper.cpp +++ b/src/ifcgeom/kernels/opencascade/faceset_helper.cpp @@ -154,7 +154,13 @@ IfcGeom::OpenCascadeKernel::faceset_helper::faceset_helper( typedef std::array edge_t; typedef std::set edge_set_t; - std::set edge_sets; + // When a single face fills an interior loop, their edge_sets (canonicalized edges) will be identical. + // We can differentiate in this scenario in two ways: + // - std::map retain the edge order from the bool passed to the loop_() lambda + // - std::pair with pair::first populated from external (FaceBound / OuterBound) + // The second has been found more reliable for typical models, because inner bound winding can be wrong. + // The can be made more resilient by first checking correct population of external and falling back to approach 1. + std::set> edge_sets; for (auto& loop : loops) { std::vector > segments; @@ -165,12 +171,12 @@ IfcGeom::OpenCascadeKernel::faceset_helper::faceset_helper( segments.push_back(std::make_pair(C, D)); }); - if (edge_sets.find(segment_set) != edge_sets.end()) { + if (edge_sets.find({loop->external.get_value_or(false), segment_set}) != edge_sets.end()) { duplicate_faces++; duplicates_.insert(loop->identity()); continue; } - edge_sets.insert(segment_set); + edge_sets.insert({loop->external.get_value_or(false), segment_set}); if (segments.size() >= 3) { for (auto& p : segments) {