From f64aea64995f6e1c4125af0de9156b3ce74f5bd8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20=C5=A0ach?= <martin.sachin@gmail.com>
Date: Fri, 2 Feb 2024 10:50:37 +0100
Subject: [PATCH] Fix: Cap speed by max_volumetric_speed even for dynamic
 overhangs.

---
 src/libslic3r/GCode.cpp                    | 41 +++++++++++-----------
 src/libslic3r/GCode/ExtrusionProcessor.cpp |  2 +-
 src/libslic3r/PrintConfig.cpp              |  3 +-
 3 files changed, 23 insertions(+), 23 deletions(-)

diff --git a/src/libslic3r/GCode.cpp b/src/libslic3r/GCode.cpp
index 6d619ef167..696aa9cb69 100644
--- a/src/libslic3r/GCode.cpp
+++ b/src/libslic3r/GCode.cpp
@@ -3040,6 +3040,20 @@ std::string GCodeGenerator::travel_to_first_position(const Vec3crd& point) {
     return gcode;
 }
 
+double cap_speed(
+    double speed, const double mm3_per_mm, const FullPrintConfig &config, int extruder_id
+) {
+    const double general_cap{config.max_volumetric_speed.value};
+    if (general_cap > 0) {
+        speed = std::min(speed, general_cap / mm3_per_mm);
+    }
+    const double filament_cap{config.filament_max_volumetric_speed.get_at(extruder_id)};
+    if (filament_cap > 0) {
+        speed = std::min(speed, filament_cap / mm3_per_mm);
+    }
+    return speed;
+}
+
 std::string GCodeGenerator::_extrude(
     const ExtrusionAttributes       &path_attr,
     const Geometry::ArcWelder::Path &path,
@@ -3139,33 +3153,15 @@ std::string GCodeGenerator::_extrude(
         speed = m_config.get_abs_value("first_layer_speed", speed);
     else if (this->object_layer_over_raft())
         speed = m_config.get_abs_value("first_layer_speed_over_raft", speed);
-    if (m_config.max_volumetric_speed.value > 0) {
-        // cap speed with max_volumetric_speed anyway (even if user is not using autospeed)
-        speed = std::min(
-            speed,
-            m_config.max_volumetric_speed.value / path_attr.mm3_per_mm
-        );
-    }
-    if (EXTRUDER_CONFIG(filament_max_volumetric_speed) > 0) {
-        // cap speed with max_volumetric_speed anyway (even if user is not using autospeed)
-        speed = std::min(
-            speed,
-            EXTRUDER_CONFIG(filament_max_volumetric_speed) / path_attr.mm3_per_mm
-        );
-    }
 
     std::pair<float, float> dynamic_speed_and_fan_speed{-1, -1};
     if (path_attr.overhang_attributes.has_value()) {
         double external_perim_reference_speed = m_config.get_abs_value("external_perimeter_speed");
         if (external_perim_reference_speed == 0)
             external_perim_reference_speed = m_volumetric_speed / path_attr.mm3_per_mm;
-        if (m_config.max_volumetric_speed.value > 0)
-            external_perim_reference_speed = std::min(external_perim_reference_speed,
-                                                      m_config.max_volumetric_speed.value / path_attr.mm3_per_mm);
-        if (EXTRUDER_CONFIG(filament_max_volumetric_speed) > 0) {
-            external_perim_reference_speed = std::min(external_perim_reference_speed,
-                                                      EXTRUDER_CONFIG(filament_max_volumetric_speed) / path_attr.mm3_per_mm);
-        }
+        external_perim_reference_speed = cap_speed(
+            external_perim_reference_speed, path_attr.mm3_per_mm, m_config, m_writer.extruder()->id()
+        );
 
         dynamic_speed_and_fan_speed = ExtrusionProcessor::calculate_overhang_speed(path_attr, this->m_config, m_writer.extruder()->id(),
                                                                                    external_perim_reference_speed, speed);
@@ -3175,6 +3171,9 @@ std::string GCodeGenerator::_extrude(
         speed = dynamic_speed_and_fan_speed.first;
     }
 
+    // cap speed with max_volumetric_speed anyway (even if user is not using autospeed)
+    speed = cap_speed(speed, path_attr.mm3_per_mm, m_config, m_writer.extruder()->id());
+
     double F = speed * 60;  // convert mm/sec to mm/min
 
     // extrude arc or line
diff --git a/src/libslic3r/GCode/ExtrusionProcessor.cpp b/src/libslic3r/GCode/ExtrusionProcessor.cpp
index 8ebc5d3df1..1e2e3bf6a4 100644
--- a/src/libslic3r/GCode/ExtrusionProcessor.cpp
+++ b/src/libslic3r/GCode/ExtrusionProcessor.cpp
@@ -213,4 +213,4 @@ std::pair<float,float> calculate_overhang_speed(const ExtrusionAttributes &attri
     return {final_speed, fan_speed};
 }
 
-}} // namespace Slic3r::ExtrusionProcessor
\ No newline at end of file
+}} // namespace Slic3r::ExtrusionProcessor
diff --git a/src/libslic3r/PrintConfig.cpp b/src/libslic3r/PrintConfig.cpp
index e72e9bff92..54d4e115c3 100644
--- a/src/libslic3r/PrintConfig.cpp
+++ b/src/libslic3r/PrintConfig.cpp
@@ -587,7 +587,8 @@ void PrintConfigDef::init_fff_params()
     auto overhang_speed_setting_description = L("Overhang size is expressed as a percentage of overlap of the extrusion with the previous layer: "
                         "100% would be full overlap (no overhang), while 0% represents full overhang (floating extrusion, bridge). "
                         "Speeds for overhang sizes in between are calculated via linear interpolation. "
-                        "If set as percentage, the speed is calculated over the external perimeter speed.");
+                        "If set as percentage, the speed is calculated over the external perimeter speed. "
+                        "Note that the speeds generated to gcode will never exceed the max volumetric speed value.");
 
     def             = this->add("overhang_speed_0", coFloatOrPercent);
     def->label      = L("speed for 0% overlap (bridge)");