From 5c7888b11453eb96a95b49dfd4cbd3b56db64eb8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Luk=C3=A1=C5=A1=20Hejl?= <hejl.lukas@gmail.com>
Date: Fri, 20 Dec 2024 12:53:54 +0100
Subject: [PATCH] Fix crash in multi-material segmentation when there wasn't
 any input polygon for some layer.

---
 src/libslic3r/MultiMaterialSegmentation.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/libslic3r/MultiMaterialSegmentation.cpp b/src/libslic3r/MultiMaterialSegmentation.cpp
index c42374ef61..cfbe9f1262 100644
--- a/src/libslic3r/MultiMaterialSegmentation.cpp
+++ b/src/libslic3r/MultiMaterialSegmentation.cpp
@@ -1801,6 +1801,9 @@ std::vector<std::vector<ExPolygons>> segmentation_by_painting(const PrintObject
             throw_on_cancel_callback();
 
             std::vector<ColorProjectionLines> &input_polygons_projection_lines = input_polygons_projection_lines_layers[layer_idx];
+            if (input_polygons_projection_lines.empty()) {
+                continue;
+            }
 
             if constexpr (MM_SEGMENTATION_DEBUG_COLOR_RANGES) {
                 export_color_projection_lines_color_ranges_to_svg(debug_out_path("mm-color-ranges-%d.svg", layer_idx), input_polygons_projection_lines, input_expolygons[layer_idx]);