From e5ca01ba9e9c380189a5677fa213b5bc217e3af2 Mon Sep 17 00:00:00 2001
From: Ioannis Giannakas <59056762+igiannakas@users.noreply.github.com>
Date: Mon, 18 May 2026 09:24:28 +0100
Subject: [PATCH] Fix per-volume "Only one wall" overrides being ignored on
 assembly parts (#13714)

---
 src/libslic3r/Layer.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/libslic3r/Layer.cpp b/src/libslic3r/Layer.cpp
index 67959a508a..0a80c019ae 100644
--- a/src/libslic3r/Layer.cpp
+++ b/src/libslic3r/Layer.cpp
@@ -159,6 +159,12 @@ bool Layer::is_perimeter_compatible(const PrintRegion& a, const PrintRegion& b)
 		&& config.detect_thin_wall                  == other_config.detect_thin_wall
 		&& config.infill_wall_overlap              == other_config.infill_wall_overlap
         && config.top_bottom_infill_wall_overlap              == other_config.top_bottom_infill_wall_overlap
+        // Orca: these flags directly change the effective wall count produced by the perimeter
+        // generator. If two regions disagree on any of them, merging their slices into one shared make_perimeters
+        // call would silently use the first region's flag for both.
+        && config.only_one_wall_first_layer == other_config.only_one_wall_first_layer
+        && config.only_one_wall_top         == other_config.only_one_wall_top
+        && config.min_width_top_surface     == other_config.min_width_top_surface
         && config.seam_slope_type         == other_config.seam_slope_type
         && config.seam_slope_conditional == other_config.seam_slope_conditional
         && config.scarf_angle_threshold  == other_config.scarf_angle_threshold