From 427f197ca98c5939e2d590130d7b201a5ff46c04 Mon Sep 17 00:00:00 2001
From: SoftFever <103989404+SoftFever@users.noreply.github.com>
Date: Fri, 16 Dec 2022 23:07:05 +0800
Subject: [PATCH] fix sandwich mode for Arachene engine

---
 src/libslic3r/PerimeterGenerator.cpp | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/libslic3r/PerimeterGenerator.cpp b/src/libslic3r/PerimeterGenerator.cpp
index 97fb33b576..b4feae31ad 100644
--- a/src/libslic3r/PerimeterGenerator.cpp
+++ b/src/libslic3r/PerimeterGenerator.cpp
@@ -1310,6 +1310,22 @@ void PerimeterGenerator::process_arachne()
             }
         }
 
+        
+        if (this->print_config->wall_infill_order == WallInfillOrder::InnerOuterInnerInfill) {
+            if (ordered_extrusions.size() > 1) {
+                std::vector<int> extPs;
+                for (int i = 0; i < ordered_extrusions.size(); ++i) {
+                    if (ordered_extrusions[i].extrusion->inset_idx == 0)
+                        extPs.push_back(i);
+                }
+                for (int i = 0; i < extPs.size(); ++i) {
+                    if (extPs[i] == 0 || (i > 0 && extPs[i] - 1 == extPs[i - 1]))
+                        continue;
+                    std::swap(ordered_extrusions[extPs[i]], ordered_extrusions[extPs[i] - 1]);
+                }
+            }
+        }
+        
         if (ExtrusionEntityCollection extrusion_coll = traverse_extrusions(*this, ordered_extrusions); !extrusion_coll.empty())
             this->loops->append(extrusion_coll);