CURA-12352 different minimum layer time for layers that contain overhangs (#2187)

Author: HellAholic

include/FanSpeedLayerTime.h

@@ -1,14 +1,16 @@
-//Copyright (c) 2020 Ultimaker B.V.
-//CuraEngine is released under the terms of the AGPLv3 or higher.
+// Copyright (c) 2020 Ultimaker B.V.
+// CuraEngine is released under the terms of the AGPLv3 or higher.
 
 #ifndef FAN_SPEED_LAYER_TIME_H
 #define FAN_SPEED_LAYER_TIME_H
 
+#include <utils/Coord_t.h>
+
 #include "settings/types/Duration.h"
 #include "settings/types/LayerIndex.h"
 #include "settings/types/Velocity.h"
 
-namespace cura 
+namespace cura
 {
 
 /*!
@@ -19,7 +21,7 @@ namespace cura
  * store these settings over and over again for each part, even though the
  * settings may be different for each part on a layer.
  */
-struct FanSpeedLayerTimeSettings 
+struct FanSpeedLayerTimeSettings
 {
 public:
     /*!
@@ -28,6 +30,16 @@ struct FanSpeedLayerTimeSettings
      */
     Duration cool_min_layer_time;
 
+    /*!
+     * Similar to Minimum layer time, but to be applied for layers that contain overhanging extrusion.
+     */
+    Duration cool_min_layer_time_overhang;
+
+    /*!
+     * The specific minimum layer time for overhanging will be applied only if there is at least one overhanging segment longer that this threshold
+     */
+    coord_t cool_min_layer_time_overhang_min_segment_length;
+
     /*!
      * "Regular/Maximum Fan Speed Threshold". If the layers take longer to print
      * than this, they'll use the regular fan speed. If they take shorter, we'll

include/LayerPlan.h

@@ -124,6 +124,10 @@ class LayerPlan : public NoCopy
     std::vector<OverhangMask> overhang_masks_; //!< The regions of a layer part where the walls overhang, calculated for multiple overhang angles. The latter is the most
                                                //!< overhanging. For a visual explanation of the result, see doc/gradual_overhang_speed.svg
     Shape seam_overhang_mask_; //!< The regions of a layer part where the walls overhang, specifically as defined for the seam
+    bool currently_overhanging_{ false }; //!< Indicates whether the last extrusion move was overhanging
+    coord_t current_overhang_length_{ 0 }; //!< When doing consecutive overhanging moves, this is the current accumulated overhanging length
+    coord_t max_overhang_length_{ 0 }; //!< From all consecutive overhanging moves in the layer, this is the longest one
+
     Shape roofing_mask_; //!< The regions of a layer part where the walls are exposed to the air
 
     bool min_layer_time_used = false; //!< Wether or not the minimum layer time (cool_min_layer_time) was actually used in this layerplan.

src/FffGcodeWriter.cpp

@@ -319,6 +319,8 @@ void FffGcodeWriter::setConfigFanSpeedLayerTime()
         fan_speed_layer_time_settings_per_extruder.emplace_back();
         FanSpeedLayerTimeSettings& fan_speed_layer_time_settings = fan_speed_layer_time_settings_per_extruder.back();
         fan_speed_layer_time_settings.cool_min_layer_time = train.settings_.get<Duration>("cool_min_layer_time");
+        fan_speed_layer_time_settings.cool_min_layer_time_overhang = train.settings_.get<Duration>("cool_min_layer_time_overhang");
+        fan_speed_layer_time_settings.cool_min_layer_time_overhang_min_segment_length = train.settings_.get<coord_t>("cool_min_layer_time_overhang_min_segment_length");
         fan_speed_layer_time_settings.cool_min_layer_time_fan_speed_max = train.settings_.get<Duration>("cool_min_layer_time_fan_speed_max");
         fan_speed_layer_time_settings.cool_fan_speed_0 = train.settings_.get<Ratio>("cool_fan_speed_0") * 100.0;
         fan_speed_layer_time_settings.cool_fan_speed_min = train.settings_.get<Ratio>("cool_fan_speed_min") * 100.0;
@@ -3112,16 +3114,18 @@ bool FffGcodeWriter::processInsets(
             {
                 AngleDegrees overhang_angle;
                 Ratio speed_factor;
+                bool chunk = true;
             };
 
             // Create raw speed regions
             const AngleDegrees overhang_step = (90.0 - wall_overhang_angle) / static_cast<double>(overhang_angles_count);
             std::vector<SpeedRegion> speed_regions;
-            speed_regions.reserve(overhang_angles_count + 1);
+            speed_regions.reserve(overhang_angles_count + 2);
 
-            speed_regions.push_back(SpeedRegion{ wall_overhang_angle, 1.0_r }); // Initial internal region, always 100% speed factor
+            constexpr bool dont_chunk_first = false; // Never merge internal region in order to detect actual overhanging
+            speed_regions.push_back(SpeedRegion{ wall_overhang_angle, 1.0_r, dont_chunk_first }); // Initial internal region, always 100% speed factor
 
-            for (size_t angle_index = 1; angle_index < overhang_angles_count; ++angle_index)
+            for (size_t angle_index = 1; angle_index <= overhang_angles_count; ++angle_index)
             {
                 const AngleDegrees actual_wall_overhang_angle = wall_overhang_angle + static_cast<double>(angle_index) * overhang_step;
                 const Ratio speed_factor = overhang_speed_factors[angle_index - 1];
@@ -3136,7 +3140,7 @@ bool FffGcodeWriter::processInsets(
                                 | ranges::views::chunk_by(
                                       [](const auto& region_a, const auto& region_b)
                                       {
-                                          return region_a.speed_factor == region_b.speed_factor;
+                                          return region_a.chunk && region_b.chunk && region_a.speed_factor == region_b.speed_factor;
                                       });
 
             // If finally necessary, add actual calculated speed regions

src/LayerPlan.cpp

@@ -568,14 +568,32 @@ void LayerPlan::addExtrusionMoveWithGradualOverhang(
     const double fan_speed,
     const bool travel_to_z)
 {
-    const auto add_extrusion_move = [&](const Point3LL& target, const Ratio& overhang_speed_factor = 1.0_r)
+    const auto add_extrusion_move = [&](const Point3LL& target, const std::optional<size_t> speed_region_index = std::nullopt)
     {
+        const Ratio overhang_speed_factor = speed_region_index.has_value() ? overhang_masks_[speed_region_index.value()].speed_ratio : 1.0_r;
         addExtrusionMove(target, config, space_fill_type, flow, width_factor, spiralize, speed_factor * overhang_speed_factor, fan_speed, travel_to_z);
     };
 
+    const auto update_is_overhanging = [this](const Point2LL& target, std::optional<Point2LL> current_position, const bool is_overhanging = false)
+    {
+        if (is_overhanging != currently_overhanging_)
+        {
+            max_overhang_length_ = std::max(current_overhang_length_, max_overhang_length_);
+            current_overhang_length_ = 0;
+        }
+
+        if (is_overhanging && current_position.has_value())
+        {
+            current_overhang_length_ += vSize(target - current_position.value());
+        }
+
+        currently_overhanging_ = is_overhanging;
+    };
+
     if (overhang_masks_.empty() || ! last_planned_position_.has_value())
     {
         // Unable to apply gradual overhanging (probably just disabled), just add the basic extrusion move
+        update_is_overhanging(p.toPoint2LL(), last_planned_position_);
         add_extrusion_move(p);
         return;
     }
@@ -619,7 +637,13 @@ void LayerPlan::addExtrusionMoveWithGradualOverhang(
         }
     };
 
-    const std::vector<SVG::Color> colors = { SVG::Color::RED, SVG::Color::GREEN, SVG::Color::BLUE, SVG::Color::YELLOW };
+    struct SegmentExtrusionMove
+    {
+        Point2LL position;
+        size_t speed_region_index;
+    };
+
+    std::vector<SegmentExtrusionMove> extrusion_moves;
 
     // Now move along segment and split it where we cross speed regions
     while (true)
@@ -658,7 +682,7 @@ void LayerPlan::addExtrusionMoveWithGradualOverhang(
 
             // Move to intersection at current region speed
             const Point2LL split_position = start + vector * intersection_parameter;
-            add_extrusion_move(split_position, overhang_masks_[actual_speed_region_index].speed_ratio);
+            extrusion_moves.push_back(SegmentExtrusionMove{ split_position, actual_speed_region_index });
 
             // Prepare for next move in different region
             actual_speed_region_index = next_speed_region_index;
@@ -667,10 +691,68 @@ void LayerPlan::addExtrusionMoveWithGradualOverhang(
         else
         {
             // We cross no border, which means we can reach the end of the segment within the current speed region, so we are done
-            add_extrusion_move(p, overhang_masks_[actual_speed_region_index].speed_ratio);
-            return;
+            extrusion_moves.push_back(SegmentExtrusionMove{ p.toPoint2LL(), actual_speed_region_index });
+            break;
+        }
+    }
+
+    // Filter out micro-segments
+    std::vector<SegmentExtrusionMove> extrusion_moves_filtered;
+    extrusion_moves_filtered.reserve(extrusion_moves.size());
+    Point2LL current_position = start;
+    for (const SegmentExtrusionMove& extrusion_move : extrusion_moves | ranges::views::drop_last(1))
+    {
+        if (vSize2(extrusion_move.position - current_position) >= MINIMUM_SQUARED_LINE_LENGTH)
+        {
+            extrusion_moves_filtered.push_back(extrusion_move);
+        }
+
+        current_position = extrusion_move.position;
+    }
+
+    if (extrusion_moves_filtered.empty() || vSize2(extrusion_moves.back().position - current_position) >= MINIMUM_SQUARED_LINE_LENGTH)
+    {
+        extrusion_moves_filtered.push_back(extrusion_moves.back());
+    }
+    else
+    {
+        extrusion_moves_filtered.back().position = extrusion_moves.back().position;
+    }
+
+    // Calculate max consecutive overhanging segment length
+    current_position = start;
+    for (const SegmentExtrusionMove& extrusion_move : extrusion_moves_filtered)
+    {
+        const bool is_overhanging = extrusion_move.speed_region_index > 0;
+        update_is_overhanging(extrusion_move.position, current_position, is_overhanging);
+        current_position = extrusion_move.position;
+    }
+
+    // Merge consecutive sub-segments that in the end have the same speed
+    std::vector<SegmentExtrusionMove> extrusion_moves_merged;
+    extrusion_moves_merged.reserve(extrusion_moves_filtered.size());
+    extrusion_moves_merged.push_back(extrusion_moves_filtered.front());
+
+    for (const SegmentExtrusionMove& extrusion_move : extrusion_moves_filtered | ranges::views::drop(1))
+    {
+        const Ratio previous_speed_factor = overhang_masks_[extrusion_moves_merged.back().speed_region_index].speed_ratio;
+        const Ratio next_speed_factor = overhang_masks_[extrusion_move.speed_region_index].speed_ratio;
+
+        if (next_speed_factor == previous_speed_factor)
+        {
+            extrusion_moves_merged.back().position = extrusion_move.position;
+        }
+        else
+        {
+            extrusion_moves_merged.push_back(extrusion_move);
         }
     }
+
+    // Finally, add extrusion moves
+    for (const SegmentExtrusionMove& extrusion_move : extrusion_moves_merged)
+    {
+        add_extrusion_move(extrusion_move.position, extrusion_move.speed_region_index);
+    }
 }
 
 template<class PathType>
@@ -2561,7 +2643,11 @@ void LayerPlan::processFanSpeedAndMinimalLayerTime(Point2LL starting_position)
             {
                 other_extr_plan_time += extruder_plan.estimates_.getTotalTime();
             }
-            maximum_cool_min_layer_time = std::max(maximum_cool_min_layer_time, extruder_plan.fan_speed_layer_time_settings_.cool_min_layer_time);
+
+            const FanSpeedLayerTimeSettings& settings = extruder_plan.fan_speed_layer_time_settings_;
+            const bool apply_minimum_layer_time_overhang = max_overhang_length_ > settings.cool_min_layer_time_overhang_min_segment_length;
+            maximum_cool_min_layer_time
+                = std::max(maximum_cool_min_layer_time, apply_minimum_layer_time_overhang ? settings.cool_min_layer_time_overhang : settings.cool_min_layer_time);
 
             // Modify fan speeds for the first layer(s)
             extruder_plan.processFanSpeedForFirstLayers();

stress_benchmark/resources/001.settings

@@ -516,7 +516,7 @@ acceleration_support_roof=300
 material_print_temp_wait=True
 support_roof_angles=[]
 machine_gcode_flavor=Griffin
-wall_overhang_speed_factor=100
+wall_overhang_speed_factors=[100]
 jerk_support_infill=12.5
 wall_0_wipe_dist=0
 jerk_wall_0_roofing=12.5

stress_benchmark/resources/002.settings

@@ -584,7 +584,7 @@ adaptive_layer_height_threshold=0.1
 support_interface_height=0.8
 support_brim_enable=True
 jerk_support_infill=8
-wall_overhang_speed_factor=100
+wall_overhang_speed_factors=[100]
 acceleration_travel=500
 support_bottom_material_flow=100
 raft_base_extruder_nr=0
@@ -972,7 +972,7 @@ extruder_prime_pos_abs=False
 support_tower_maximum_supported_diameter=3.0
 support_tree_angle=45
 jerk_support_infill=8
-wall_overhang_speed_factor=100
+wall_overhang_speed_factors=[100]
 infill_before_walls=False
 material=0
 brim_width=8.0

stress_benchmark/resources/003.settings

@@ -585,7 +585,7 @@ adaptive_layer_height_threshold=0.2
 support_interface_height=0.96
 support_brim_enable=True
 jerk_support_infill=12.0
-wall_overhang_speed_factor=100
+wall_overhang_speed_factors=[100]
 acceleration_travel=500
 support_bottom_material_flow=95.0
 raft_base_extruder_nr=0
@@ -973,7 +973,7 @@ extruder_prime_pos_abs=False
 support_tower_maximum_supported_diameter=3.0
 support_tree_angle=50
 jerk_support_infill=12.0
-wall_overhang_speed_factor=100
+wall_overhang_speed_factors=[100]
 infill_before_walls=False
 material=0
 brim_width=8.0

stress_benchmark/resources/004.settings

@@ -585,7 +585,7 @@ adaptive_layer_height_threshold=0.2
 support_interface_height=0.8
 support_brim_enable=True
 jerk_support_infill=8
-wall_overhang_speed_factor=100
+wall_overhang_speed_factors=[100]
 acceleration_travel=500
 support_bottom_material_flow=100
 raft_base_extruder_nr=0
@@ -973,7 +973,7 @@ extruder_prime_pos_abs=False
 support_tower_maximum_supported_diameter=3.0
 support_tree_angle=55
 jerk_support_infill=8
-wall_overhang_speed_factor=100
+wall_overhang_speed_factors=[100]
 infill_before_walls=False
 material=0
 brim_width=8.0

stress_benchmark/resources/005.settings

@@ -586,7 +586,7 @@ adaptive_layer_height_threshold=0.2
 support_interface_height=0.8
 support_brim_enable=True
 jerk_support_infill=8
-wall_overhang_speed_factor=100
+wall_overhang_speed_factors=[100]
 acceleration_travel=500
 support_bottom_material_flow=100
 raft_base_extruder_nr=0
@@ -974,7 +974,7 @@ extruder_prime_pos_abs=False
 support_tower_maximum_supported_diameter=3.0
 support_tree_angle=65.0
 jerk_support_infill=8
-wall_overhang_speed_factor=100
+wall_overhang_speed_factors=[100]
 infill_before_walls=False
 material=0
 brim_width=3

stress_benchmark/resources/006.settings

@@ -586,7 +586,7 @@ adaptive_layer_height_threshold=0.2
 support_interface_height=0.8
 support_brim_enable=True
 jerk_support_infill=8
-wall_overhang_speed_factor=100
+wall_overhang_speed_factors=[100]
 acceleration_travel=500
 support_bottom_material_flow=100
 raft_base_extruder_nr=0
@@ -974,7 +974,7 @@ extruder_prime_pos_abs=False
 support_tower_maximum_supported_diameter=3.0
 support_tree_angle=60.0
 jerk_support_infill=8
-wall_overhang_speed_factor=100
+wall_overhang_speed_factors=[100]
 infill_before_walls=False
 material=0
 brim_width=8.0