From 36528738fe4acb4b53cc021870ad277a70dcde91 Mon Sep 17 00:00:00 2001
From: "salt.wei" <salt.wei@bambulab.com>
Date: Fri, 19 Aug 2022 17:59:29 +0800
Subject: [PATCH] ENH: force retraction and wiping when leave external wall

This can reduce dragging and reduce seams

Signed-off-by: salt.wei <salt.wei@bambulab.com>
Change-Id: I60e3c11493ca9ef00a8fd22c437f67cddac32724
---
 src/libslic3r/GCode.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/libslic3r/GCode.cpp b/src/libslic3r/GCode.cpp
index 74b4035957..3142d491a3 100644
--- a/src/libslic3r/GCode.cpp
+++ b/src/libslic3r/GCode.cpp
@@ -3798,6 +3798,11 @@ bool GCode::needs_retraction(const Polyline &travel, ExtrusionRole role)
         return false;
     }
 
+    //BBS: force to retract when leave from external perimeter for a long travel
+    //Better way is judging whether the travel move direction is same with last extrusion move.
+    if (is_perimeter(m_last_processor_extrusion_role) && m_last_processor_extrusion_role != erPerimeter)
+        return true;
+
     if (role == erSupportMaterial || role == erSupportTransition) {
         const SupportLayer* support_layer = dynamic_cast<const SupportLayer*>(m_layer);
         //FIXME support_layer->support_islands.contains should use some search structure!