From 454363fe2c255af5744645d7f8f2058f890ae8a4 Mon Sep 17 00:00:00 2001
From: Filip Sykala - NTB T15p <Filip.Sykala@prusa3d.cz>
Date: Fri, 13 Jan 2023 13:27:01 +0100
Subject: [PATCH] Fix of filtering trinagles for reflected projection

---
 src/libslic3r/CutSurface.cpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/libslic3r/CutSurface.cpp b/src/libslic3r/CutSurface.cpp
index 88e3bba75..c484bba22 100644
--- a/src/libslic3r/CutSurface.cpp
+++ b/src/libslic3r/CutSurface.cpp
@@ -768,6 +768,15 @@ void priv::set_skip_for_out_of_aoi(std::vector<bool>          &skip_indicies,
 
         point_normals[i] = {p1, normal};
     }
+
+    // check that projection is not left handed
+    // Fix for reflected projection
+    if (is_out_of(point_normals[2].first, point_normals[0])) {
+        // projection is reflected so normals are reflected
+        for (auto &pn : point_normals)
+            pn.second *= -1;
+    }    
+
     // same meaning as point normal
     IsOnSides is_on_sides(its.vertices.size(), {false,false,false,false});