From 91b1d469eb01a918d7ea824065d60787ad3db1e5 Mon Sep 17 00:00:00 2001
From: tamasmeszaros <meszaros.q@gmail.com>
Date: Thu, 3 Dec 2020 14:16:13 +0100
Subject: [PATCH 1/2] Fix arrange with malformed contours

---
 src/libslic3r/Arrange.cpp | 11 +++++++----
 src/libslic3r/Model.cpp   |  2 --
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/libslic3r/Arrange.cpp b/src/libslic3r/Arrange.cpp
index bb13a9a0a..3800d49e3 100644
--- a/src/libslic3r/Arrange.cpp
+++ b/src/libslic3r/Arrange.cpp
@@ -572,10 +572,13 @@ static void process_arrangeable(const ArrangePolygon &arrpoly,
 
     clppr::Polygon clpath(Slic3rMultiPoint_to_ClipperPath(p));
 
-    if (!clpath.Contour.empty()) {
-        auto firstp = clpath.Contour.front();
-        clpath.Contour.emplace_back(firstp);
-    }
+    // This fixes:
+    // https://github.com/prusa3d/PrusaSlicer/issues/2209
+    if (clpath.Contour.size() < 3)
+        return;
+
+    auto firstp = clpath.Contour.front();
+    clpath.Contour.emplace_back(firstp);
 
     outp.emplace_back(std::move(clpath));
     outp.back().rotation(rotation);
diff --git a/src/libslic3r/Model.cpp b/src/libslic3r/Model.cpp
index b06b1f347..c0258e719 100644
--- a/src/libslic3r/Model.cpp
+++ b/src/libslic3r/Model.cpp
@@ -1858,8 +1858,6 @@ arrangement::ArrangePolygon ModelInstance::get_arrange_polygon() const
 
     assert(!p.points.empty());
 
-    // this may happen for malformed models, see:
-    // https://github.com/prusa3d/PrusaSlicer/issues/2209
 //    if (!p.points.empty()) {
 //        Polygons pp{p};
 //        pp = p.simplify(scaled<double>(SIMPLIFY_TOLERANCE_MM));

From 310de2f2ef8bcbe46643b4edb65018856d122c79 Mon Sep 17 00:00:00 2001
From: tamasmeszaros <meszaros.q@gmail.com>
Date: Thu, 3 Dec 2020 14:58:56 +0100
Subject: [PATCH 2/2] Fix crash when splitting objects

fixes partially #2209
---
 src/libslic3r/Model.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/libslic3r/Model.cpp b/src/libslic3r/Model.cpp
index c0258e719..5887931df 100644
--- a/src/libslic3r/Model.cpp
+++ b/src/libslic3r/Model.cpp
@@ -1273,6 +1273,10 @@ void ModelObject::split(ModelObjectPtrs* new_objects)
     ModelVolume* volume = this->volumes.front();
     TriangleMeshPtrs meshptrs = volume->mesh().split();
     for (TriangleMesh *mesh : meshptrs) {
+
+        // FIXME: crashes if not satisfied
+        if (mesh->facets_count() < 3) continue;
+
         mesh->repair();
         
         // XXX: this seems to be the only real usage of m_model, maybe refactor this so that it's not needed?