From a1b8ae1cb9dc31a4847251283c0043d476ea8076 Mon Sep 17 00:00:00 2001
From: Simon Kueppers <simon.kueppers@skueppers.de>
Date: Tue, 23 Jan 2024 19:51:57 +0100
Subject: [PATCH] Implemented Outer/Outer/inner wall sequence for classic
 slicer as Outer/Inner mode, but first and second external perimeters are
 swapped. This improves overhang performance at the cost of a slight decrease
 in print quality

---
 src/libslic3r/PerimeterGenerator.cpp | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/src/libslic3r/PerimeterGenerator.cpp b/src/libslic3r/PerimeterGenerator.cpp
index 02586fbcb2e..ba0c2212d28 100644
--- a/src/libslic3r/PerimeterGenerator.cpp
+++ b/src/libslic3r/PerimeterGenerator.cpp
@@ -1738,6 +1738,24 @@ void PerimeterGenerator::process_classic()
                     this->object_config->brim_type == BrimType::btOuterOnly &&
                     this->object_config->brim_width.value > 0))
                 entities.reverse();
+            else if (this->config->wall_sequence == WallSequence::OuterOuterInner)
+                if (entities.entities.size() > 1) {
+                    entities.reverse();
+
+                    int swapped = 0;
+                    int index;
+
+                    for (index=0; index < entities.entities.size(); index++) {
+                        if (entities.entities[index]->role() == erExternalPerimeter) {
+                            if (swapped == 0 && (index+1) < entities.entities.size()) {
+                                std::swap(entities.entities[index], entities.entities[index+1]);
+                                swapped = 1;
+                            }
+                        } else {
+                            swapped = 0;
+                        }
+                    }
+                }
             // SoftFever: sandwich mode 
             else if (this->config->wall_sequence == WallSequence::InnerOuterInner)
                 if (entities.entities.size() > 1){