Enhancement: Adaptive Pressure advance (#5609)

* Adaptive Pressure advance options setup

* Dynamic PA - PCHIP interpolator code and tests

* Integrate dynamic PA with slicing code - emit new PA values per speed change

* Link adaptive PA to role change instead of speed change

* Adaptive PA - Alpha 2

Reduce the frequency of requested PA changes by introducing a "state" variable.
Implement user toggle for adapting PA for external walls for overhangs

* Hide adaptive PA for overhangs

* Convert Adaptive PA to use volumetric flow model and start preparing for converting to Gcode post processor

* Converted Dynamic PA to a post processing filter. Reverted changes in GCode cpp and created tagging mechanism to allow filter to apply PA changes.

* Removed adaptive PA for overhangs

* Foundations for two dimensional adaptive PA based on acceleration and volumetric flow speed

* Minor code cleanup and updating of tooltips

* Renaming files for better clarity and generate classes documentation

* Update src/libslic3r/PrintConfig.cpp

Co-authored-by: ElectricalBoy <15651807+ElectricalBoy@users.noreply.github.com>

* Update src/libslic3r/PrintConfig.cpp

Co-authored-by: ElectricalBoy <15651807+ElectricalBoy@users.noreply.github.com>

* Update src/libslic3r/PrintConfig.cpp

Co-authored-by: ElectricalBoy <15651807+ElectricalBoy@users.noreply.github.com>

* Introduce average mm3_mm over the length of a multipath for adaptive PA

* Updates for multipath handling part 2

* Introduce average mm3_mm over the length of a multipath for adaptive PA

* Trigger PA evaluation more frequently to catch edge cases where speed changes across islands of the same feature type.

* Updates for multipath handling part 2

* Adaptive PA: Implement average flow estimation on loops

* Code formatting

* Fix adaptive PA not adapting for small disconnected external wall line segments.

* Updated to take max print speed of upcoming feature to calculate new PA value.

This is to resolve issue of incorrect PA value used when starting a new feature at an overhang.

* Code clean up

* Performance tuning

* Further performance tuning by reducing use of regex commands in the nested loops and fix bug preventing gcode line output

* Further performance tuning and tweaks to stop searching for max speed after the first travel move.

* Reduce debug information

* Updated debug info

* Fix an issue on seams on specific models when wipe before external perimeter was enabled. Also cleanup documentation and add new to-do's

* Prepare for adaptive PA for overhangs, fix wipe bug & clean up code and comments

* Initial commit for adapting PA when extruding fully overhanging perimeters

* Ignore wipe command when identifying current print speed

* Option to evaluate adaptive PA on overhang regions in preparation for Klipper experimental option testing

* Update to issue PA changes for varying flow conditions within the same feature

* Fix bug where adaptive PA was enabled erroneously for role changes and ignoring user's preference.

* Refactored some code

* More refactoring

* Some bug fixes and enabled comments only when verbose g-code is enabled

* Introduced dedicated PA option for bridges

* Code refactoring to optimise initialisation of PA processor (making it faster). Fix a bug where PA was not always set after a toolchange. Improve general error handling and robustness.

* Updates to adaptive PA tooltips

* Bridging PA check with Epsilon instead of 0.

* Adaptive PA: addressing comments

---------

Co-authored-by: ElectricalBoy <15651807+ElectricalBoy@users.noreply.github.com>

src/libslic3r/CMakeLists.txt

@@ -156,6 +156,12 @@ set(lisbslic3r_sources
     GCode/RetractWhenCrossingPerimeters.hpp
     GCode/SmallAreaInfillFlowCompensator.cpp
     GCode/SmallAreaInfillFlowCompensator.hpp
+    GCode/PchipInterpolatorHelper.cpp
+    GCode/PchipInterpolatorHelper.hpp
+    GCode/AdaptivePAInterpolator.cpp
+    GCode/AdaptivePAInterpolator.hpp
+    GCode/AdaptivePAProcessor.cpp
+    GCode/AdaptivePAProcessor.hpp
     GCode/SpiralVase.cpp
     GCode/SpiralVase.hpp
     GCode/SeamPlacer.cpp

src/libslic3r/GCode.cpp

@@ -668,6 +668,9 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
         // SoftFever: set new PA for new filament
         if (gcodegen.config().enable_pressure_advance.get_at(new_extruder_id)) {
             gcode += gcodegen.writer().set_pressure_advance(gcodegen.config().pressure_advance.get_at(new_extruder_id));
+            // Orca: Adaptive PA
+            // Reset Adaptive PA processor last PA value
+            gcodegen.m_pa_processor->resetPreviousPA(gcodegen.config().pressure_advance.get_at(new_extruder_id));
         }
 
         // A phony move to the end position at the wipe tower.
@@ -856,6 +859,9 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
         // SoftFever: set new PA for new filament
         if (new_extruder_id != -1 && gcodegen.config().enable_pressure_advance.get_at(new_extruder_id)) {
             gcode += gcodegen.writer().set_pressure_advance(gcodegen.config().pressure_advance.get_at(new_extruder_id));
+            // Orca: Adaptive PA
+            // Reset Adaptive PA processor last PA value
+            gcodegen.m_pa_processor->resetPreviousPA(gcodegen.config().pressure_advance.get_at(new_extruder_id));
         }
 
         // A phony move to the end position at the wipe tower.
@@ -1980,6 +1986,7 @@ void GCode::_do_export(Print& print, GCodeOutputStream &file, ThumbnailsGenerato
     if (!print.config().small_area_infill_flow_compensation_model.empty())
         m_small_area_infill_flow_compensator = make_unique<SmallAreaInfillFlowCompensator>(print.config());
     
+
     file.write_format("; HEADER_BLOCK_START\n");
     // Write information on the generator.
     file.write_format("; generated by %s on %s\n", Slic3r::header_slic3r_generated().c_str(), Slic3r::Utils::local_timestamp().c_str());
@@ -2228,6 +2235,9 @@ void GCode::_do_export(Print& print, GCodeOutputStream &file, ThumbnailsGenerato
     m_cooling_buffer = make_unique<CoolingBuffer>(*this);
     m_cooling_buffer->set_current_extruder(initial_extruder_id);
     
+    // Orca: Initialise AdaptivePA processor filter
+    m_pa_processor = std::make_unique<AdaptivePAProcessor>(*this, tool_ordering.all_extruders());
+
     // Emit machine envelope limits for the Marlin firmware.
     this->print_machine_envelope(file, print);
 
@@ -2870,6 +2880,12 @@ void GCode::process_layers(
                 return in.gcode;
             return cooling_buffer.process_layer(std::move(in.gcode), in.layer_id, in.cooling_buffer_flush);
         });
+    const auto pa_processor_filter = tbb::make_filter<std::string, std::string>(slic3r_tbb_filtermode::serial_in_order,
+            [&pa_processor = *this->m_pa_processor](std::string in) -> std::string {
+                return pa_processor.process_layer(std::move(in));
+            }
+        );
+    
     const auto output = tbb::make_filter<std::string, void>(slic3r_tbb_filtermode::serial_in_order,
         [&output_stream](std::string s) { output_stream.write(s); }
     );
@@ -2900,9 +2916,9 @@ void GCode::process_layers(
     else if (m_spiral_vase)
     	tbb::parallel_pipeline(12, generator & spiral_mode & cooling & fan_mover & output);
     else if	(m_pressure_equalizer)
-        tbb::parallel_pipeline(12, generator & pressure_equalizer & cooling & fan_mover & output);
+        tbb::parallel_pipeline(12, generator & pressure_equalizer & cooling & fan_mover & pa_processor_filter & output);
     else
-    	tbb::parallel_pipeline(12, generator & cooling & fan_mover & output);
+    	tbb::parallel_pipeline(12, generator & cooling & fan_mover & pa_processor_filter & output);
 }
 
 // Process all layers of a single object instance (sequential mode) with a parallel pipeline:
@@ -4548,6 +4564,7 @@ static std::unique_ptr<EdgeGrid::Grid> calculate_layer_edge_grid(const Layer& la
 
 std::string GCode::extrude_loop(ExtrusionLoop loop, std::string description, double speed, const ExtrusionEntitiesPtr& region_perimeters)
 {
+    
     // get a copy; don't modify the orientation of the original loop object otherwise
     // next copies (if any) would not detect the correct orientation
 
@@ -4673,7 +4690,9 @@ std::string GCode::extrude_loop(ExtrusionLoop loop, std::string description, dou
         if(discoveredTouchingLines > 1){
             // use extrude instead of travel_to_xy to trigger the unretract
             ExtrusionPath fake_path_wipe(Polyline{pt, current_point}, paths.front());
+            fake_path_wipe.set_force_no_extrusion(true);
             fake_path_wipe.mm3_per_mm = 0;
+            //fake_path_wipe.set_extrusion_role(erExternalPerimeter);
             gcode += extrude_path(fake_path_wipe, "move inwards before retraction/seam", speed);
         }
     }
@@ -4685,9 +4704,32 @@ std::string GCode::extrude_loop(ExtrusionLoop loop, std::string description, dou
         return is_small_peri ? small_peri_speed : speed;
     };
 
+    
+    //Orca: Adaptive PA: calculate average mm3_per_mm value over the length of the loop.
+    //This is used for adaptive PA
+    m_multi_flow_segment_path_pa_set = false; // always emit PA on the first path of the loop
+    m_multi_flow_segment_path_average_mm3_per_mm = 0;
+    double weighted_sum_mm3_per_mm = 0.0;
+    double total_multipath_length = 0.0;
+    for (const ExtrusionPath& path : paths) {
+        if(!path.is_force_no_extrusion()){
+            double path_length = unscale<double>(path.length()); //path length in mm
+            weighted_sum_mm3_per_mm += path.mm3_per_mm * path_length;
+            total_multipath_length += path_length;
+        }
+    }
+    if (total_multipath_length > 0.0)
+        m_multi_flow_segment_path_average_mm3_per_mm = weighted_sum_mm3_per_mm / total_multipath_length;
+    // Orca: end of multipath average mm3_per_mm value calculation
+    
     if (!enable_seam_slope) {
         for (ExtrusionPaths::iterator path = paths.begin(); path != paths.end(); ++path) {
             gcode += this->_extrude(*path, description, speed_for_path(*path));
+            // Orca: Adaptive PA - dont adapt PA after the first pultipath extrusion is completed
+            // as we have already set the PA value to the average flow over the totality of the path
+            // in the first extrude move
+            // TODO: testing is needed with slope seams and adaptive PA.
+            m_multi_flow_segment_path_pa_set = true;
         }
     } else {
         // Create seam slope
@@ -4719,6 +4761,10 @@ std::string GCode::extrude_loop(ExtrusionLoop loop, std::string description, dou
         // Then extrude it
         for (const auto& p : new_loop.get_all_paths()) {
             gcode += this->_extrude(*p, description, speed_for_path(*p));
+            // Orca: Adaptive PA - dont adapt PA after the first pultipath extrusion is completed
+            // as we have already set the PA value to the average flow over the totality of the path
+            // in the first extrude move
+            m_multi_flow_segment_path_pa_set = true;
         }
 
         // Fix path for wipe
@@ -4790,8 +4836,31 @@ std::string GCode::extrude_multi_path(ExtrusionMultiPath multipath, std::string
 {
     // extrude along the path
     std::string gcode;
-    for (ExtrusionPath path : multipath.paths)
+    
+    //Orca: calculate multipath average mm3_per_mm value over the length of the path.
+    //This is used for adaptive PA
+    m_multi_flow_segment_path_pa_set = false; // always emit PA on the first path of the multi-path
+    m_multi_flow_segment_path_average_mm3_per_mm = 0;
+    double weighted_sum_mm3_per_mm = 0.0;
+    double total_multipath_length = 0.0;
+    for (const ExtrusionPath& path : multipath.paths) {
+        if(!path.is_force_no_extrusion()){
+            double path_length = unscale<double>(path.length()); //path length in mm
+            weighted_sum_mm3_per_mm += path.mm3_per_mm * path_length;
+            total_multipath_length += path_length;
+        }
+    }
+    if (total_multipath_length > 0.0)
+        m_multi_flow_segment_path_average_mm3_per_mm = weighted_sum_mm3_per_mm / total_multipath_length;
+    // Orca: end of multipath average mm3_per_mm value calculation
+    
+    for (ExtrusionPath path : multipath.paths){
         gcode += this->_extrude(path, description, speed);
+        // Orca: Adaptive PA - dont adapt PA after the first pultipath extrusion is completed
+        // as we have already set the PA value to the average flow over the totality of the path
+        // in the first extrude move.
+        m_multi_flow_segment_path_pa_set = true;
+    }
 
     // BBS
     if (m_wipe.enable) {
@@ -4825,7 +4894,10 @@ std::string GCode::extrude_entity(const ExtrusionEntity &entity, std::string des
 
 std::string GCode::extrude_path(ExtrusionPath path, std::string description, double speed)
 {
-//    description += ExtrusionEntity::role_to_string(path.role());
+    // Orca: Reset average multipath flow as this is a single line, single extrude volumetric speed path
+    m_multi_flow_segment_path_pa_set = false;
+    m_multi_flow_segment_path_average_mm3_per_mm = 0;
+    //    description += ExtrusionEntity::role_to_string(path.role());
     std::string gcode = this->_extrude(path, description, speed);
     if (m_wipe.enable) {
         m_wipe.path = std::move(path.polyline);
@@ -5292,6 +5364,27 @@ std::string GCode::_extrude(const ExtrusionPath &path, std::string description,
 
     double F = speed * 60;  // convert mm/sec to mm/min
     
+    // Orca: Dynamic PA
+    // If adaptive PA is enabled, by default evaluate PA on all extrusion moves
+    bool evaluate_adaptive_pa = false;
+    bool role_change = (m_last_extrusion_role != path.role());
+    if(EXTRUDER_CONFIG(adaptive_pressure_advance) && EXTRUDER_CONFIG(enable_pressure_advance)){
+        evaluate_adaptive_pa = true;
+        // If we have already emmited a PA change because the m_multi_flow_segment_path_pa_set is set
+        // skip re-issuing the PA change tag.
+        if (m_multi_flow_segment_path_pa_set && evaluate_adaptive_pa)
+            evaluate_adaptive_pa = false;
+        // TODO: Explore forcing evaluation of PA if a role change is happening mid extrusion.
+        // TODO: This would enable adapting PA for overhang perimeters as they are part of the current loop
+        // TODO: The issue with simply enabling PA evaluation on a role change is that the speed change
+        // TODO: is issued before the overhang perimeter role change is triggered
+        // TODO: because for some reason (maybe path segmentation upstream?) there is a short path extruded
+        // TODO: with the overhang speed and flow before the role change is flagged in the path.role() function.
+        if(role_change)
+            evaluate_adaptive_pa = true;
+    }
+    // Orca: End of dynamic PA trigger flag segment
+    
     //Orca: process custom gcode for extrusion role change
     if (path.role() != m_last_extrusion_role && !m_config.change_extrusion_role_gcode.value.empty()) {
             DynamicConfig config;
@@ -5348,6 +5441,45 @@ std::string GCode::_extrude(const ExtrusionPath &path, std::string description,
         gcode += buf;
     }
     
+    // Orca: Dynamic PA
+    // Post processor flag generation code segment when option to emit only at role changes is enabled
+    // Variables published to the post processor:
+    // 1) Tag to trigger a PA evaluation (because a role change was identified and the user has requested dynamic PA adjustments)
+    // 2) Current extruder ID (to identify the PA model for the currently used extruder)
+    // 3) mm3_per_mm value (to then multiply by the final model print speed after slowdown for cooling is applied)
+    // 4) the current acceleration (to pass to the model for evaluation)
+    // 5) whether this is an external perimeter (for future use)
+    // 6) whether this segment is triggered because of a role change (to aid in calculation of average speed for the role)
+    // This tag simplifies the creation of the gcode post processor while also keeping the feature decoupled from other tags.
+    if (evaluate_adaptive_pa) {
+        bool isOverhangPerimeter = (path.role() == erOverhangPerimeter);
+        if (m_multi_flow_segment_path_average_mm3_per_mm > 0) {
+            sprintf(buf, ";%sT%u MM3MM:%g ACCEL:%u BR:%d RC:%d OV:%d\n",
+                    GCodeProcessor::reserved_tag(GCodeProcessor::ETags::PA_Change).c_str(),
+                    m_writer.extruder()->id(),
+                    m_multi_flow_segment_path_average_mm3_per_mm,
+                    acceleration_i,
+                    ((path.role() == erBridgeInfill) ||(path.role() == erOverhangPerimeter)),
+                    role_change,
+                    isOverhangPerimeter);
+            gcode += buf;
+        } else if(_mm3_per_mm >0 ){ // Triggered when extruding a single segment path (like a line).
+                                    // Check if mm3_mm value is greater than zero as the wipe before external perimeter
+                                    // is a zero mm3_mm path to force de-retraction to happen and we dont want
+                                    // to issue a zero flow PA change command for this
+            sprintf(buf, ";%sT%u MM3MM:%g ACCEL:%u BR:%d RC:%d OV:%d\n",
+                    GCodeProcessor::reserved_tag(GCodeProcessor::ETags::PA_Change).c_str(),
+                    m_writer.extruder()->id(),
+                    _mm3_per_mm,
+                    acceleration_i,
+                    ((path.role() == erBridgeInfill) ||(path.role() == erOverhangPerimeter)),
+                    role_change,
+                    isOverhangPerimeter);
+            gcode += buf;
+        }
+    }
+
+
     auto overhang_fan_threshold = EXTRUDER_CONFIG(overhang_fan_threshold);
     auto enable_overhang_bridge_fan = EXTRUDER_CONFIG(enable_overhang_bridge_fan);
     
@@ -5397,6 +5529,54 @@ std::string GCode::_extrude(const ExtrusionPath &path, std::string description,
 
     if (!variable_speed) {
         // F is mm per minute.
+        if( (std::abs(writer().get_current_speed() - F) > EPSILON) || (std::abs(_mm3_per_mm - m_last_mm3_mm) > EPSILON) ){
+            // ORCA: Adaptive PA code segment when adjusting PA within the same feature
+            // There is a speed change coming out of an overhang region
+            // or a flow change, so emit the flag to evaluate PA for the upcomming extrusion
+            // Emit tag before new speed is set so the post processor reads the next speed immediately and uses it.
+            // Dont emit tag if it has just already been emitted from a role change above
+            if(_mm3_per_mm >0 &&
+               EXTRUDER_CONFIG(adaptive_pressure_advance) &&
+               EXTRUDER_CONFIG(enable_pressure_advance) &&
+               EXTRUDER_CONFIG(adaptive_pressure_advance_overhangs) &&
+               !evaluate_adaptive_pa){
+                if(writer().get_current_speed() > F){ // Ramping down speed - use overhang logic where the minimum speed is used between current and upcoming extrusion
+                    if(m_config.gcode_comments){
+                        sprintf(buf, "; Ramp down-non-variable\n");
+                        gcode += buf;
+                    }
+                    sprintf(buf, ";%sT%u MM3MM:%g ACCEL:%u BR:%d RC:%d OV:%d\n",
+                            GCodeProcessor::reserved_tag(GCodeProcessor::ETags::PA_Change).c_str(),
+                            m_writer.extruder()->id(),
+                            _mm3_per_mm,
+                            acceleration_i,
+                            ((path.role() == erBridgeInfill) ||(path.role() == erOverhangPerimeter)),
+                            1, // Force a dummy "role change" & "overhang perimeter" for the post processor, as, while technically it is not a role change,
+                            // the properties of the extrusion in the overhang are different so it behaves similarly to a role
+                            // change for the Adaptive PA post processor.
+                            1);
+                }else{ // Ramping up speed - use baseline logic where max speed is used between current and upcoming extrusion
+                    if(m_config.gcode_comments){ 
+                        sprintf(buf, "; Ramp up-non-variable\n");
+                        gcode += buf;
+                    }
+                    sprintf(buf, ";%sT%u MM3MM:%g ACCEL:%u BR:%d RC:%d OV:%d\n",
+                            GCodeProcessor::reserved_tag(GCodeProcessor::ETags::PA_Change).c_str(),
+                            m_writer.extruder()->id(),
+                            _mm3_per_mm,
+                            acceleration_i,
+                            ((path.role() == erBridgeInfill) ||(path.role() == erOverhangPerimeter)),
+                            1, // Force a dummy "role change" & "overhang perimeter" for the post processor, as, while technically it is not a role change,
+                            // the properties of the extrusion in the overhang are different so it is technically similar to a role
+                            // change for the Adaptive PA post processor.
+                            0);
+                }
+                gcode += buf;
+                m_last_mm3_mm = _mm3_per_mm;
+            }
+            // ORCA: End of adaptive PA code segment
+        }
+        
         gcode += m_writer.set_speed(F, "", comment);
         {
             if (m_enable_cooling_markers) {
@@ -5591,6 +5771,52 @@ std::string GCode::_extrude(const ExtrusionPath &path, std::string description,
                 continue;
             path_length += line_length;
             double new_speed = pre_processed_point.speed * 60.0;
+            
+            if ((std::abs(last_set_speed - new_speed) > EPSILON) || (std::abs(_mm3_per_mm - m_last_mm3_mm) > EPSILON)) {
+                // ORCA: Adaptive PA code segment when adjusting PA within the same feature
+                // There is a speed change or flow change so emit the flag to evaluate PA for the upcomming extrusion
+                // Emit tag before new speed is set so the post processor reads the next speed immediately and uses it.
+                if(_mm3_per_mm >0   &&
+                   EXTRUDER_CONFIG(adaptive_pressure_advance) &&
+                   EXTRUDER_CONFIG(enable_pressure_advance) &&
+                   EXTRUDER_CONFIG(adaptive_pressure_advance_overhangs) ){
+                    if(last_set_speed > new_speed){ // Ramping down speed - use overhang logic where the minimum speed is used between current and upcoming extrusion
+                        if(m_config.gcode_comments) {
+                            sprintf(buf, "; Ramp up-variable\n");
+                            gcode += buf;
+                        }
+                        sprintf(buf, ";%sT%u MM3MM:%g ACCEL:%u BR:%d RC:%d OV:%d\n",
+                                GCodeProcessor::reserved_tag(GCodeProcessor::ETags::PA_Change).c_str(),
+                                m_writer.extruder()->id(),
+                                _mm3_per_mm,
+                                acceleration_i,
+                                ((path.role() == erBridgeInfill) ||(path.role() == erOverhangPerimeter)),
+                                1, // Force a dummy "role change" & "overhang perimeter" for the post processor, as, while technically it is not a role change,
+                                // the properties of the extrusion in the overhang are different so it is technically similar to a role
+                                // change for the Adaptive PA post processor.
+                                1);
+                    }else{ // Ramping up speed - use baseline logic where max speed is used between current and upcoming extrusion
+                        if(m_config.gcode_comments) {
+                            sprintf(buf, "; Ramp down-variable\n");
+                            gcode += buf;
+                        }
+                        sprintf(buf, ";%sT%u MM3MM:%g ACCEL:%u BR:%d RC:%d OV:%d\n",
+                                GCodeProcessor::reserved_tag(GCodeProcessor::ETags::PA_Change).c_str(),
+                                m_writer.extruder()->id(),
+                                _mm3_per_mm,
+                                acceleration_i,
+                                ((path.role() == erBridgeInfill) ||(path.role() == erOverhangPerimeter)),
+                                1, // Force a dummy "role change" & "overhang perimeter" for the post processor, as, while technically it is not a role change,
+                                // the properties of the extrusion in the overhang are different so it is technically similar to a role
+                                // change for the Adaptive PA post processor.
+                                0);
+                    }
+                    gcode += buf;
+                    m_last_mm3_mm = _mm3_per_mm;
+                }
+            }// ORCA: End of adaptive PA code segment
+            
+            
             if (last_set_speed != new_speed) {
                 gcode += m_writer.set_speed(new_speed, "", comment);
                 last_set_speed = new_speed;
@@ -6029,6 +6255,9 @@ std::string GCode::set_extruder(unsigned int extruder_id, double print_z, bool b
         }
         if (m_config.enable_pressure_advance.get_at(extruder_id)) {
             gcode += m_writer.set_pressure_advance(m_config.pressure_advance.get_at(extruder_id));
+            // Orca: Adaptive PA
+            // Reset Adaptive PA processor last PA value
+            m_pa_processor->resetPreviousPA(m_config.pressure_advance.get_at(extruder_id));
         }
 
         gcode += m_writer.toolchange(extruder_id);

src/libslic3r/GCode.hpp

@@ -24,6 +24,8 @@
 
 #include "GCode/PressureEqualizer.hpp"
 #include "GCode/SmallAreaInfillFlowCompensator.hpp"
+// ORCA: post processor below used for Dynamic Pressure advance
+#include "GCode/AdaptivePAProcessor.hpp"
 
 #include <memory>
 #include <map>
@@ -359,6 +361,19 @@ private:
     std::string     extrude_multi_path(ExtrusionMultiPath multipath, std::string description = "", double speed = -1.);
     std::string     extrude_path(ExtrusionPath path, std::string description = "", double speed = -1.);
     
+    // Orca: Adaptive PA variables
+    // Used for adaptive PA when extruding paths with multiple, varying flow segments.
+    // This contains the sum of the mm3_per_mm values weighted by the length of each path segment.
+    // The m_multi_flow_segment_path_pa_set constrains the PA change request to the first extrusion segment.
+    // It sets the mm3_mm value for the adaptive PA post processor to be the average of that path
+    // as calculated and stored in the m_multi_segment_path_average_mm3_per_mm value
+    double          m_multi_flow_segment_path_average_mm3_per_mm = 0;
+    bool            m_multi_flow_segment_path_pa_set = false;
+    // Adaptive PA last set flow to enable issuing of PA change commands when adaptive PA for overhangs
+    // is enabled
+    double          m_last_mm3_mm = 0;
+    // Orca: Adaptive PA code segment end
+
     // Extruding multiple objects with soluble / non-soluble / combined supports
     // on a multi-material printer, trying to minimize tool switches.
     // Following structures sort extrusions by the extruder ID, by an order of objects and object islands.
@@ -541,6 +556,8 @@ private:
 
     std::unique_ptr<PressureEqualizer>  m_pressure_equalizer;
     
+    std::unique_ptr<AdaptivePAProcessor>      m_pa_processor;
+
     std::unique_ptr<WipeTowerIntegration> m_wipe_tower;
 
     std::unique_ptr<SmallAreaInfillFlowCompensator> m_small_area_infill_flow_compensator;

src/libslic3r/GCode/AdaptivePAInterpolator.cpp

@@ -0,0 +1,114 @@
+// AdaptivePAInterpolator.cpp
+// OrcaSlicer
+//
+// Implementation file for the AdaptivePAInterpolator class, providing methods to parse data and perform PA interpolation.
+
+#include "AdaptivePAInterpolator.hpp"
+#include <stdexcept>
+#include <cmath>
+#include <algorithm>
+#include <sstream>
+
+/**
+ * @brief Parses the input data and sets up the interpolators.
+ * @param data A string containing the data in CSV format (PA, flow rate, acceleration).
+ * @return 0 on success, -1 on error.
+ */
+int AdaptivePAInterpolator::parseAndSetData(const std::string& data) {
+    flow_interpolators_.clear();
+    accelerations_.clear();
+
+    try {
+        std::istringstream ss(data);
+        std::string line;
+        std::map<double, std::vector<std::pair<double, double>>> acc_to_flow_pa;
+
+        while (std::getline(ss, line)) {
+            std::istringstream lineStream(line);
+            std::string value;
+            double paValue, flowRate, acceleration;
+            paValue = flowRate = acceleration = 0.f; // initialize all to zero.
+
+            // Parse PA value
+            if (std::getline(lineStream, value, ',')) {
+                paValue = std::stod(value);
+            }
+
+            // Parse flow rate value
+            if (std::getline(lineStream, value, ',')) {
+                flowRate = std::stod(value);
+            }
+
+            // Parse acceleration value
+            if (std::getline(lineStream, value, ',')) {
+                acceleration = std::stod(value);
+            }
+
+            // Store the parsed values in a map with acceleration as the key
+            acc_to_flow_pa[acceleration].emplace_back(flowRate, paValue);
+        }
+
+        // Iterate through the map to set up the interpolators
+        for (const auto& kv : acc_to_flow_pa) {
+            double acceleration = kv.first;
+            const auto& data = kv.second;
+
+            std::vector<double> flowRates;
+            std::vector<double> paValues;
+
+            for (const auto& pair : data) {
+                flowRates.push_back(pair.first);
+                paValues.push_back(pair.second);
+            }
+
+            // Only set up the interpolator if there are enough data points
+            if (flowRates.size() > 1) {
+                PchipInterpolatorHelper interpolator(flowRates, paValues);
+                flow_interpolators_[acceleration] = interpolator;
+                accelerations_.push_back(acceleration);
+            }
+        }
+    } catch (const std::exception&) {
+        m_isInitialised = false;
+        return -1; // Error: Exception during parsing
+    }
+    m_isInitialised = true;
+    return 0; // Success
+}
+
+/**
+ * @brief Interpolates the PA value for the given flow rate and acceleration.
+ * @param flow_rate The flow rate at which to interpolate.
+ * @param acceleration The acceleration at which to interpolate.
+ * @return The interpolated PA value, or -1 if interpolation fails.
+ */
+double AdaptivePAInterpolator::operator()(double flow_rate, double acceleration) {
+    std::vector<double> pa_values;
+    std::vector<double> acc_values;
+
+    // Estimate PA value for every flow to PA model for the given flow rate
+    for (const auto& kv : flow_interpolators_) {
+        double pa_value = kv.second.interpolate(flow_rate);
+        
+        // Check if the interpolated PA value is valid
+        if (pa_value != -1) {
+            pa_values.push_back(pa_value);
+            acc_values.push_back(kv.first);
+        }
+    }
+
+    // Check if there are enough acceleration values for interpolation
+    if (acc_values.size() < 2) {
+        // Special case: Only one acceleration value
+        if (acc_values.size() == 1) {
+            return std::round(pa_values[0] * 1000.0) / 1000.0; // Rounded to 3 decimal places
+        }
+        return -1; // Error: Not enough data points for interpolation
+    }
+
+    // Create a new PchipInterpolatorHelper for PA-acceleration interpolation
+    // Use the estimated PA values from the for loop above and their corresponding accelerations to
+    // generate the new PCHIP model. Then run this model to interpolate the PA value for the given acceleration value.
+    PchipInterpolatorHelper pa_accel_interpolator(acc_values, pa_values);
+    return std::round(pa_accel_interpolator.interpolate(acceleration) * 1000.0) / 1000.0; // Rounded to 3 decimal places
+}

src/libslic3r/GCode/AdaptivePAInterpolator.hpp

@@ -0,0 +1,54 @@
+// AdaptivePAInterpolator.hpp
+// OrcaSlicer
+//
+// Header file for the AdaptivePAInterpolator class, responsible for interpolating pressure advance (PA) values based on flow rate and acceleration using PCHIP interpolation.
+
+#ifndef ADAPTIVEPAINTERPOLATOR_HPP
+#define ADAPTIVEPAINTERPOLATOR_HPP
+
+#include <vector>
+#include <string>
+#include <map>
+#include "PchipInterpolatorHelper.hpp"
+
+/**
+ * @class AdaptivePAInterpolator
+ * @brief A class to interpolate pressure advance (PA) values based on flow rate and acceleration using Piecewise Cubic Hermite Interpolating Polynomial (PCHIP) interpolation.
+ */
+class AdaptivePAInterpolator {
+public:
+    /**
+     * @brief Default constructor.
+     */
+    AdaptivePAInterpolator() : m_isInitialised(false) {}
+
+    /**
+     * @brief Parses the input data and sets up the interpolators.
+     * @param data A string containing the data in CSV format (PA, flow rate, acceleration).
+     * @return 0 on success, -1 on error.
+     */
+    int parseAndSetData(const std::string& data);
+
+    /**
+     * @brief Interpolates the PA value for the given flow rate and acceleration.
+     * @param flow_rate The flow rate at which to interpolate.
+     * @param acceleration The acceleration at which to interpolate.
+     * @return The interpolated PA value, or -1 if interpolation fails.
+     */
+    double operator()(double flow_rate, double acceleration);
+    
+    /**
+     * @brief Returns the initialization status.
+     * @return The value of m_isInitialised.
+     */
+    bool isInitialised() const {
+        return m_isInitialised;
+    }
+
+private:
+    std::map<double, PchipInterpolatorHelper> flow_interpolators_; ///< Map each acceleration to a flow-rate-to-PA interpolator.
+    std::vector<double> accelerations_; ///< Store unique accelerations.
+    bool m_isInitialised;
+};
+
+#endif // ADAPTIVEPAINTERPOLATOR_HPP

src/libslic3r/GCode/AdaptivePAProcessor.cpp

@@ -0,0 +1,285 @@
+// AdaptivePAProcessor.cpp
+// OrcaSlicer
+//
+// Implementation of the AdaptivePAProcessor class, responsible for processing G-code layers with adaptive pressure advance.
+
+#include "../GCode.hpp"
+#include "AdaptivePAProcessor.hpp"
+#include <sstream>
+#include <iostream>
+#include <cmath>
+
+namespace Slic3r {
+
+/**
+ * @brief Constructor for AdaptivePAProcessor.
+ *
+ * This constructor initializes the AdaptivePAProcessor with a reference to a GCode object.
+ * It also initializes the configuration reference, pressure advance interpolation object,
+ * and regular expression patterns used for processing the G-code.
+ *
+ * @param gcodegen A reference to the GCode object that generates the G-code.
+ */
+AdaptivePAProcessor::AdaptivePAProcessor(GCode &gcodegen, const std::vector<unsigned int> &tools_used)
+    : m_gcodegen(gcodegen),
+      m_config(gcodegen.config()),
+      m_last_predicted_pa(0.0),
+      m_max_next_feedrate(0.0),
+      m_next_feedrate(0.0),
+      m_current_feedrate(0.0),
+      m_last_extruder_id(-1),
+      m_pa_change_pattern(R"(; PA_CHANGE:T(\d+) MM3MM:([0-9]*\.[0-9]+) ACCEL:(\d+) BR:(\d+) RC:(\d+) OV:(\d+))"),
+      m_g1_f_pattern(R"(G1 F([0-9]+))")
+{
+    // Constructor body can be used for further initialization if necessary
+    for (unsigned int tool : tools_used) {
+        // Only enable model for the tool if both PA and adaptive PA options are enabled
+        if(m_config.adaptive_pressure_advance.get_at(tool) && m_config.enable_pressure_advance.get_at(tool)){
+            auto interpolator = std::make_unique<AdaptivePAInterpolator>();
+            // Get calibration values from extruder
+            std::string pa_calibration_values = m_config.adaptive_pressure_advance_model.get_at(tool);
+            // Setup the model and store it in the tool-interpolation model map
+            interpolator->parseAndSetData(pa_calibration_values);
+            m_AdaptivePAInterpolators[tool] = std::move(interpolator);
+        }
+    }
+}
+
+// Method to get the interpolator for a specific tool ID
+AdaptivePAInterpolator* AdaptivePAProcessor::getInterpolator(unsigned int tool_id) {
+    auto it = m_AdaptivePAInterpolators.find(tool_id);
+    if (it != m_AdaptivePAInterpolators.end()) {
+        return it->second.get();
+    }
+    return nullptr;  // Handle the case where the tool_id is not found
+}
+
+/**
+ * @brief Processes a layer of G-code and applies adaptive pressure advance.
+ *
+ * This method processes the G-code for a single layer, identifying the appropriate
+ * pressure advance settings and applying them based on the current state and configurations.
+ *
+ * @param gcode A string containing the G-code for the layer.
+ * @return A string containing the processed G-code with adaptive pressure advance applied.
+ */
+std::string AdaptivePAProcessor::process_layer(std::string &&gcode) {
+    std::istringstream stream(gcode);
+    std::string line;
+    std::ostringstream output;
+    double mm3mm_value = 0.0;
+    unsigned int accel_value = 0;
+    std::string pa_change_line;
+    bool wipe_command = false;
+
+    // Iterate through each line of the layer G-code
+    while (std::getline(stream, line)) {
+        
+        // If a wipe start command is found, ignore all speed changes till the wipe end part is found
+        if (line.find("WIPE_START") != std::string::npos) {
+            wipe_command = true;
+        }
+                
+        // Update current feed rate (this is preceding an extrude or wipe command only). Ignore any speed changes that are emitted during a wipe move.
+        // Travel feedrate is output as part of a G1 X Y (Z) F command
+        if ( (line.find("G1 F") == 0) && (!wipe_command) ) { // prune lines quickly before running pattern matching
+            std::size_t pos = line.find('F');
+            if (pos != std::string::npos){
+                m_current_feedrate = std::stod(line.substr(pos + 1)) / 60.0; // Convert from mm/min to mm/s
+            }
+        }
+        
+        // Wipe end found, continue searching for current feed rate.
+        if (line.find("WIPE_END") != std::string::npos) {
+            wipe_command = false;
+        }
+        
+        // Reset next feedrate to zero enable searching for the first encountered
+        // feedrate change command after the PA change tag.
+        m_next_feedrate = 0;
+        
+        // Check for PA_CHANGE pattern in the line
+        // We will only find this pattern for extruders where adaptive PA is enabled.
+        // If there is mixed extruders in the layer (i.e. with adaptive PA on and off
+        // this will only update the extruders where the adaptive PA is enabled
+        // as these are the only ones where the PA pattern is output
+        // For a mixed extruder layer with both adaptive PA enabled and disabled when the new tool is selected
+        // the PA for that material is set. As no tag below will be found for this extruder, the original PA is retained.
+        if (line.find("; PA_CHANGE") == 0) { // prune lines quickly before running regex check as regex is more expensive to run
+            if (std::regex_search(line, m_match, m_pa_change_pattern)) {
+                int extruder_id = std::stoi(m_match[1].str());
+                mm3mm_value = std::stod(m_match[2].str());
+                accel_value = std::stod(m_match[3].str());
+                int isBridge = std::stoi(m_match[4].str());
+                int roleChange = std::stoi(m_match[5].str());
+                int isOverhang = std::stoi(m_match[6].str());
+                
+                // Check if the extruder ID has changed
+                bool extruder_changed = (extruder_id != m_last_extruder_id);
+                m_last_extruder_id = extruder_id;
+                
+                // Save the PA_CHANGE line to output later after finding feedrate
+                pa_change_line = line;
+                
+                // Look ahead for feedrate before any line containing both G and E commands
+                std::streampos current_pos = stream.tellg();
+                std::string next_line;
+                double temp_feed_rate = 0;
+                bool extrude_move_found = false;
+                int line_counter = 0;
+                
+                // Carry on searching on the layer gcode lines to find the print speed
+                // If a G1 Fxxxx pattern is found, the new speed is identified
+                // Carry on searching for feedrates to find the maximum print speed
+                // until a feature change pattern or a wipe command is detected
+                while (std::getline(stream, next_line)) {
+                    line_counter++;
+                    // Found an extrude move, set extrude move found flag and move to the next line
+                    if ((!extrude_move_found) && next_line.find("G1 ") == 0 &&
+                        next_line.find('X') != std::string::npos &&
+                        next_line.find('Y') != std::string::npos &&
+                        next_line.find('E') != std::string::npos) {
+                        // Pattern matched, break the loop
+                        extrude_move_found = true;
+                        continue;
+                    }
+                    
+                    // Found a travel move after we've found at least one extrude move
+                    // We now need to stop searching for speeds as we're done printing this island
+                    if (next_line.find("G1 ") == 0 &&
+                        next_line.find('X') != std::string::npos && // X is present
+                        next_line.find('Y') != std::string::npos && // Y is present
+                        next_line.find('E') == std::string::npos && // no "E" present
+                        extrude_move_found) {                       // An extrude move has happened already
+                        // First travel move after extrude move found. Stop searching
+                        break;
+                    }
+                    
+                    // Found a WIPE command
+                    // If we have a wipe command, usually the wipe speed is different (larger) than the max print speed
+                    // for that feature. So stop searching if a wipe command is found because we do not want to overwrite the
+                    // speed used for PA calculation by the Wipe speed.
+                    if (next_line.find("WIPE") != std::string::npos) {
+                        break; // Stop searching if wipe command is found
+                    }
+                    
+                    // Found another PA_CHANGE pattern
+                    // If RC = 1, it means we have a role change, so stop trying to find the max speed for the feature.
+                    // This is possibly redundant as a new feature would always have a travel move preceding it
+                    // but check anyway. However check last so to not invoke it without reason...
+                    if (next_line.find("; PA_CHANGE") == 0) { // prune lines quickly before running pattern matching
+                        std::size_t rc_pos = next_line.rfind("RC:");
+                        if (rc_pos != std::string::npos) {
+                            int rc_value = std::stoi(next_line.substr(rc_pos + 3));
+                            if (rc_value == 1) {
+                                break; // Role change found, stop searching
+                            }
+                        }
+                    }
+                    
+                    // Found a Feedrate change command
+                    // If the new feedrate is greater than any feedrate encountered so far after the PA change command, use that to calculate the PA value
+                    // Also if this is the first feedrate we encounter, store it as the next feedrate.
+                    if (next_line.find("G1 F") == 0) { // prune lines quickly before running pattern matching
+                        std::size_t pos = next_line.find('F');
+                        if (pos != std::string::npos) {
+                            double feedrate = std::stod(next_line.substr(pos + 1)) / 60.0; // Convert from mm/min to mm/s
+                            if(line_counter==1){ // this is the first command after the PA change pattern, and hence before any extrusion has happened. Reset
+                                                // the current speed to this one
+                                m_current_feedrate = feedrate;
+                            }
+                            if (temp_feed_rate < feedrate) {
+                                temp_feed_rate = feedrate;
+                            }
+                            if(m_next_feedrate < EPSILON){ // This the first feedrate found after the PA Change command
+                                m_next_feedrate = feedrate;
+                            }
+                        }
+                        continue;
+                    }
+                }
+                
+                // If we found a new maximum feedrate after the PA change command, use it
+                if (temp_feed_rate > 0) {
+                    m_max_next_feedrate = temp_feed_rate;
+                } else // If we didnt find a new feedrate at all after the PA change command, use the current feedrate.
+                    m_max_next_feedrate = m_current_feedrate;
+                
+                // Restore stream position
+                stream.clear();
+                stream.seekg(current_pos);
+                
+                // Calculate the predicted PA using the upcomming feature maximum feedrate
+                // Get the interpolator for the active tool
+                AdaptivePAInterpolator* interpolator = getInterpolator(m_last_extruder_id);
+                
+                double predicted_pa = 0;
+                double adaptive_PA_speed = 0;
+            
+                if(!interpolator){ // Tool not found in the interpolator map
+                    // Tool not found in the PA interpolator to tool map
+                    predicted_pa = m_config.enable_pressure_advance.get_at(m_last_extruder_id) ? m_config.pressure_advance.get_at(m_last_extruder_id) : 0;
+                    if(m_config.gcode_comments) output << "; APA: Tool doesnt have APA enabled\n";
+                } else if (!interpolator->isInitialised() || (!m_config.adaptive_pressure_advance.get_at(m_last_extruder_id)) )
+                    // Check if the model is not initialised by the constructor for the active extruder
+                    // Also check that adaptive PA is enabled for that extruder. This should not be needed
+                    // as the PA change flag should not be set upstream (in the GCode.cpp file) if adaptive PA is disabled
+                    // however check for robustness sake.
+                {
+                    // Model failed or adaptive pressure advance not enabled - use default value from m_config
+                    predicted_pa = m_config.enable_pressure_advance.get_at(m_last_extruder_id) ? m_config.pressure_advance.get_at(m_last_extruder_id) : 0;
+                    if(m_config.gcode_comments) output << "; APA: Interpolator setup failed, using default pressure advance\n";
+                } else { // Model setup succeeded
+                    // Proceed to identify the print speed to use to calculate the adaptive PA value
+                    if(isOverhang > 0){  // If we are in an overhang area, use the minimum between current print speed
+                                        // and any speed immediately after
+                                        // In most cases the current speed is the minimum one;
+                                        // however if slowdown for layer cooling is enabled, the overhang
+                                        // may be slowed down more than the current speed.
+                        adaptive_PA_speed = (m_current_feedrate == 0 || m_next_feedrate == 0) ?
+                                                std::max(m_current_feedrate, m_next_feedrate) :
+                                                std::min(m_current_feedrate, m_next_feedrate);
+                    }else{                // If this is not an overhang area, use the maximum speed from the current and
+                                          // upcomming speeds for the island.
+                        adaptive_PA_speed = std::max(m_max_next_feedrate,m_current_feedrate);
+                    }
+                    
+                    // Calculate the adaptive PA value
+                    predicted_pa = (*interpolator)(mm3mm_value * adaptive_PA_speed, accel_value);
+                    
+                    // This is a bridge, use the dedicated PA setting.
+                    if(isBridge && m_config.adaptive_pressure_advance_bridges.get_at(m_last_extruder_id) > EPSILON)
+                        predicted_pa = m_config.adaptive_pressure_advance_bridges.get_at(m_last_extruder_id);
+                    
+                    if (predicted_pa < 0) { // If extrapolation fails, fall back to the default PA for the extruder.
+                        predicted_pa = m_config.enable_pressure_advance.get_at(m_last_extruder_id) ? m_config.pressure_advance.get_at(m_last_extruder_id) : 0;
+                        if(m_config.gcode_comments) output << "; APA: Interpolation failed, using fallback pressure advance value\n";
+                    }
+                }
+                if(m_config.gcode_comments) {
+                    // Output debug GCode comments
+                    output << pa_change_line << '\n'; // Output PA change command tag
+                    if(isBridge && m_config.adaptive_pressure_advance_bridges.get_at(m_last_extruder_id) > EPSILON)
+                        output << "; APA Model Override (bridge)\n";
+                    output << "; APA Current Speed: " << std::to_string(m_current_feedrate) << "\n";
+                    output << "; APA Next Speed: " << std::to_string(m_next_feedrate) << "\n";
+                    output << "; APA Max Next Speed: " << std::to_string(m_max_next_feedrate) << "\n";
+                    output << "; APA Speed Used: " << std::to_string(adaptive_PA_speed) << "\n";
+                    output << "; APA Flow rate: " << std::to_string(mm3mm_value * m_max_next_feedrate) << "\n";
+                    output << "; APA Prev PA: " << std::to_string(m_last_predicted_pa) << " New PA: " << std::to_string(predicted_pa) << "\n"; 
+                }
+                if (extruder_changed || std::fabs(predicted_pa - m_last_predicted_pa) > EPSILON) {
+                    output << m_gcodegen.writer().set_pressure_advance(predicted_pa); // Use m_writer to set pressure advance
+                    m_last_predicted_pa = predicted_pa; // Update the last predicted PA value
+                }
+            }
+        }else {
+            // Output the current line as this isn't a PA change tag
+            output << line << '\n';
+        }
+    }
+
+    return output.str();
+}
+
+} // namespace Slic3r

src/libslic3r/GCode/AdaptivePAProcessor.hpp

@@ -0,0 +1,85 @@
+// AdaptivePAProcessor.hpp
+// OrcaSlicer
+//
+// Header file for the AdaptivePAProcessor class, responsible for processing G-code layers for the purposes of applying adaptive pressure advance.
+
+#ifndef ADAPTIVEPAPROCESSOR_H
+#define ADAPTIVEPAPROCESSOR_H
+
+#include <string>
+#include <sstream>
+#include <regex>
+#include <memory>
+#include <map>
+#include <vector>
+#include "AdaptivePAInterpolator.hpp"
+
+namespace Slic3r {
+
+// Forward declaration of GCode class
+class GCode;
+
+/**
+ * @brief Class for processing G-code layers with adaptive pressure advance.
+ */
+class AdaptivePAProcessor {
+public:
+    /**
+     * @brief Constructor for AdaptivePAProcessor.
+     *
+     * This constructor initializes the AdaptivePAProcessor with a reference to a GCode object.
+     * It also initializes the configuration reference, pressure advance interpolation object,
+     * and regular expression patterns used for processing the G-code.
+     *
+     * @param gcodegen A reference to the GCode object that generates the G-code.
+     */
+    AdaptivePAProcessor(GCode &gcodegen, const std::vector<unsigned int> &tools_used);
+    
+    /**
+     * @brief Processes a layer of G-code and applies adaptive pressure advance.
+     *
+     * This method processes the G-code for a single layer, identifying the appropriate
+     * pressure advance settings and applying them based on the current state and configurations.
+     *
+     * @param gcode A string containing the G-code for the layer.
+     * @return A string containing the processed G-code with adaptive pressure advance applied.
+     */
+    std::string process_layer(std::string &&gcode);
+    
+    /**
+     * @brief Manually sets adaptive PA internal value.
+     *
+     * This method manually sets the adaptive PA internally held value.
+     * Call this when changing tools or in any other case where the internally assumed last PA value may be incorrect
+     */
+    void resetPreviousPA(double PA){ m_last_predicted_pa = PA; };
+    
+private:
+    GCode &m_gcodegen; ///< Reference to the GCode object.
+    std::unordered_map<unsigned int, std::unique_ptr<AdaptivePAInterpolator>> m_AdaptivePAInterpolators; ///< Map between Interpolator objects and tool ID's
+    const PrintConfig &m_config; ///< Reference to the print configuration.
+    double m_last_predicted_pa; ///< Last predicted pressure advance value.
+    double m_max_next_feedrate; ///< Maximum feed rate (speed) for the upcomming island. If no speed is found, the previous island speed is used.
+    double m_next_feedrate; ///< First feed rate (speed) for the upcomming island.
+    double m_current_feedrate; ///< Current, latest feedrate.
+    int m_last_extruder_id; ///< Last used extruder ID.
+
+    std::regex m_pa_change_pattern; ///< Regular expression to detect PA_CHANGE pattern.
+    std::regex m_g1_f_pattern; ///< Regular expression to detect G1 F pattern.
+    std::smatch m_match; ///< Match results for regular expressions.
+
+    /**
+     * @brief Get the PA interpolator attached to the specified tool ID.
+     *
+     * This method manually sets the adaptive PA internally held value.
+     * Call this when changing tools or in any other case where the internally assumed last PA value may be incorrect
+     *
+     * @param An integer with the tool ID for which the PA interpolation model is to be returned.
+     * @return The Adaptive PA Interpolator object corresponding to that tool.
+     */
+    AdaptivePAInterpolator* getInterpolator(unsigned int tool_id);
+};
+
+} // namespace Slic3r
+
+#endif // ADAPTIVEPAPROCESSOR_H

src/libslic3r/GCode/GCodeProcessor.cpp

@@ -68,7 +68,8 @@ const std::vector<std::string> GCodeProcessor::Reserved_Tags = {
     " MANUAL_TOOL_CHANGE ",
     "_DURING_PRINT_EXHAUST_FAN",
     " WIPE_TOWER_START",
-    " WIPE_TOWER_END"
+    " WIPE_TOWER_END",
+    " PA_CHANGE:"
 };
 
 const std::vector<std::string> GCodeProcessor::Reserved_Tags_compatible = {
@@ -88,7 +89,8 @@ const std::vector<std::string> GCodeProcessor::Reserved_Tags_compatible = {
     " MANUAL_TOOL_CHANGE ",
     "_DURING_PRINT_EXHAUST_FAN",
     " WIPE_TOWER_START",
-    " WIPE_TOWER_END"
+    " WIPE_TOWER_END",
+    " PA_CHANGE:"
 };
 
 

src/libslic3r/GCode/GCodeProcessor.hpp

@@ -291,6 +291,7 @@ namespace Slic3r {
             During_Print_Exhaust_Fan,
             Wipe_Tower_Start,
             Wipe_Tower_End,
+            PA_Change,
         };
 
         static const std::string& reserved_tag(ETags tag) { return s_IsBBLPrinter ? Reserved_Tags[static_cast<unsigned char>(tag)] : Reserved_Tags_compatible[static_cast<unsigned char>(tag)]; }

src/libslic3r/GCode/PchipInterpolatorHelper.cpp

@@ -0,0 +1,100 @@
+// PchipInterpolatorHelper.cpp
+// OrcaSlicer
+//
+// Implementation file for the PchipInterpolatorHelper class
+
+#include "PchipInterpolatorHelper.hpp"
+#include <stdexcept>
+#include <cmath>
+#include <algorithm>
+
+/**
+ * @brief Constructs the PCHIP interpolator with given data points.
+ * @param x The x-coordinates of the data points.
+ * @param y The y-coordinates of the data points.
+ */
+PchipInterpolatorHelper::PchipInterpolatorHelper(const std::vector<double>& x, const std::vector<double>& y) {
+    setData(x, y);
+}
+
+/**
+ * @brief Sets the data points for the interpolator.
+ * @param x The x-coordinates of the data points.
+ * @param y The y-coordinates of the data points.
+ * @throw std::invalid_argument if x and y have different sizes or if they contain fewer than two points.
+ */
+void PchipInterpolatorHelper::setData(const std::vector<double>& x, const std::vector<double>& y) {
+    if (x.size() != y.size() || x.size() < 2) {
+        throw std::invalid_argument("Input vectors must have the same size and contain at least two points.");
+    }
+    x_ = x;
+    y_ = y;
+    sortData();
+    computePCHIP();
+}
+
+/**
+ * @brief Sorts the data points by x-coordinate.
+ */
+void PchipInterpolatorHelper::sortData() {
+    std::vector<std::pair<double, double>> data;
+    for (size_t i = 0; i < x_.size(); ++i) {
+        data.emplace_back(x_[i], y_[i]);
+    }
+    std::sort(data.begin(), data.end());
+
+    for (size_t i = 0; i < data.size(); ++i) {
+        x_[i] = data[i].first;
+        y_[i] = data[i].second;
+    }
+}
+
+/**
+ * @brief Computes the PCHIP coefficients.
+ */
+void PchipInterpolatorHelper::computePCHIP() {
+    size_t n = x_.size() - 1;
+    h_.resize(n);
+    delta_.resize(n);
+    d_.resize(n+1);
+
+    for (size_t i = 0; i < n; ++i) {
+        h_[i] = h(i);
+        delta_[i] = delta(i);
+    }
+
+    d_[0] = delta_[0];
+    d_[n] = delta_[n-1];
+    for (size_t i = 1; i < n; ++i) {
+        if (delta_[i-1] * delta_[i] > 0) {
+            double w1 = 2 * h_[i] + h_[i-1];
+            double w2 = h_[i] + 2 * h_[i-1];
+            d_[i] = (w1 + w2) / (w1 / delta_[i-1] + w2 / delta_[i]);
+        } else {
+            d_[i] = 0;
+        }
+    }
+}
+
+/**
+ * @brief Interpolates the value at a given point.
+ */
+double PchipInterpolatorHelper::interpolate(double xi) const {
+    if (xi <= x_.front()) return y_.front();
+    if (xi >= x_.back()) return y_.back();
+
+    auto it = std::lower_bound(x_.begin(), x_.end(), xi);
+    size_t i = std::distance(x_.begin(), it) - 1;
+
+    double h_i = h_[i];
+    double t = (xi - x_[i]) / h_i;
+    double t2 = t * t;
+    double t3 = t2 * t;
+
+    double h00 = 2 * t3 - 3 * t2 + 1;
+    double h10 = t3 - 2 * t2 + t;
+    double h01 = -2 * t3 + 3 * t2;
+    double h11 = t3 - t2;
+
+    return h00 * y_[i] + h10 * h_i * d_[i] + h01 * y_[i+1] + h11 * h_i * d_[i+1];
+}

src/libslic3r/GCode/PchipInterpolatorHelper.hpp

@@ -0,0 +1,76 @@
+// PchipInterpolatorHelper.hpp
+// OrcaSlicer
+//
+// Header file for the PchipInterpolatorHelper class, responsible for performing Piecewise Cubic Hermite Interpolating Polynomial (PCHIP) interpolation on given data points.
+
+#ifndef PCHIPINTERPOLATORHELPER_HPP
+#define PCHIPINTERPOLATORHELPER_HPP
+
+#include <vector>
+
+/**
+ * @class PchipInterpolatorHelper
+ * @brief A helper class to perform Piecewise Cubic Hermite Interpolating Polynomial (PCHIP) interpolation.
+ */
+class PchipInterpolatorHelper {
+public:
+    /**
+     * @brief Default constructor.
+     */
+    PchipInterpolatorHelper() = default;
+
+    /**
+     * @brief Constructs the PCHIP interpolator with given data points.
+     * @param x The x-coordinates of the data points.
+     * @param y The y-coordinates of the data points.
+     */
+    PchipInterpolatorHelper(const std::vector<double>& x, const std::vector<double>& y);
+
+    /**
+     * @brief Sets the data points for the interpolator.
+     * @param x The x-coordinates of the data points.
+     * @param y The y-coordinates of the data points.
+     * @throw std::invalid_argument if x and y have different sizes or if they contain fewer than two points.
+     */
+    void setData(const std::vector<double>& x, const std::vector<double>& y);
+
+    /**
+     * @brief Interpolates the value at a given point.
+     * @param xi The x-coordinate at which to interpolate.
+     * @return The interpolated y-coordinate.
+     */
+    double interpolate(double xi) const;
+
+private:
+    std::vector<double> x_; ///< The x-coordinates of the data points.
+    std::vector<double> y_; ///< The y-coordinates of the data points.
+    std::vector<double> h_; ///< The differences between successive x-coordinates.
+    std::vector<double> delta_; ///< The slopes of the segments between successive data points.
+    std::vector<double> d_; ///< The derivatives at the data points.
+
+    /**
+     * @brief Computes the PCHIP coefficients.
+     */
+    void computePCHIP();
+
+    /**
+     * @brief Sorts the data points by x-coordinate.
+     */
+    void sortData();
+
+    /**
+     * @brief Computes the difference between successive x-coordinates.
+     * @param i The index of the x-coordinate.
+     * @return The difference between x_[i+1] and x_[i].
+     */
+    double h(int i) const { return x_[i+1] - x_[i]; }
+
+    /**
+     * @brief Computes the slope of the segment between successive data points.
+     * @param i The index of the segment.
+     * @return The slope of the segment between y_[i] and y_[i+1].
+     */
+    double delta(int i) const { return (y_[i+1] - y_[i]) / h(i); }
+};
+
+#endif // PCHIPINTERPOLATORHELPER_HPP

src/libslic3r/Preset.cpp

@@ -840,7 +840,7 @@ static std::vector<std::string> s_Preset_filament_options {
     "filament_wipe_distance", "additional_cooling_fan_speed",
     "nozzle_temperature_range_low", "nozzle_temperature_range_high",
     //SoftFever
-    "enable_pressure_advance", "pressure_advance","chamber_temperature", "filament_shrink", "support_material_interface_fan_speed", "filament_notes" /*,"filament_seam_gap"*/,
+    "enable_pressure_advance", "pressure_advance","adaptive_pressure_advance","adaptive_pressure_advance_model","adaptive_pressure_advance_overhangs", "adaptive_pressure_advance_bridges","chamber_temperature", "filament_shrink", "support_material_interface_fan_speed", "filament_notes" /*,"filament_seam_gap"*/,
     "filament_loading_speed", "filament_loading_speed_start", "filament_load_time",
     "filament_unloading_speed", "filament_unloading_speed_start", "filament_unload_time", "filament_toolchange_delay", "filament_cooling_moves",
     "filament_cooling_initial_speed", "filament_cooling_final_speed", "filament_ramming_parameters",

src/libslic3r/PrintConfig.cpp

@@ -1682,6 +1682,60 @@ void PrintConfigDef::init_fff_params()
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionFloats { 0.02 });
     
+    // Orca: Adaptive pressure advance option and calibration values
+    def = this->add("adaptive_pressure_advance", coBools);
+    def->label = L("Enable adaptive pressure advance (beta)");
+    def->tooltip = L("With increasing print speeds (and hence increasing volumetric flow through the nozzle) and increasing accelerations, "
+                     "it has been observed that the effective PA value typically decreases. "
+                     "This means that a single PA value is not always 100% optimal for all features and a compromise value is usually used "
+                     "that does not cause too much bulging on features with lower flow speed and accelerations while also not causing gaps on faster features.\n\n"
+                     "This feature aims to address this limitation by modeling the response of your printer's extrusion system depending "
+                     "on the volumetric flow speed and acceleration it is printing at. Internally, it generates a fitted model that can extrapolate the needed pressure "
+                     "advance for any given volumetric flow speed and acceleration, which is then emmited to the printer depending on the current print conditions.\n\n"
+                     "When enabled, the pressure advance value above is overriden. However, a reasonable default value above is "
+                     "strongly recomended to act as a fallback and for when tool changing.\n\n");
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionBools{ false });
+    
+    // Orca: Adaptive pressure advance option and calibration values
+    def = this->add("adaptive_pressure_advance_model", coStrings);
+    def->label = L("Adaptive pressure advance measurements (beta)");
+    def->tooltip = L("Add sets of pressure advance (PA) values, the volumetric flow speeds and accelerations they were measured at, separated by a comma. "
+                     "One set of values per line. For example\n"
+                     "0.04,3.96,3000\n0.033,3.96,10000\n0.029,7.91,3000\n0.026,7.91,10000\n\n"
+                     "How to calibrate:\n"
+                     "1. Run the pressure advance test for at least 3 speeds per acceleration value. It is recommended that the test is run "
+                     "for at least the speed of the external perimeters, the speed of the internal perimeters and the fastest feature "
+                     "print speed in your profile (usually its the sparse or solid infill). Then run them for the same speeds for the slowest and fastest print accelerations,"
+                     "and no faster than the recommended maximum acceleration as given by the klipper input shaper.\n"
+                     "2. Take note of the optimal PA value for each volumetric flow speed and acceleration. You can find the flow number by selecting "
+                     "flow from the color scheme drop down and move the horizontal slider over the PA pattern lines. The number should be visible "
+                     "at the bottom of the page. The ideal PA value should be decreasing the higher the volumetric flow is. If it is not, confirm that your extruder is functioning correctly."
+                     "The slower and with less acceleration you print, the larger the range of acceptable PA values. If no difference is visible, use the PA value from the faster test."
+                     "3. Enter the triplets of PA values, Flow and Accelerations in the text box here and save your filament profile\n\n"
+                     "");
+    def->mode = comAdvanced;
+    //def->gui_flags = "serialized";
+    def->multiline = true;
+    def->full_width = true;
+    def->height = 15;
+    def->set_default_value(new ConfigOptionStrings{"0,0,0\n0,0,0"});
+    
+    def = this->add("adaptive_pressure_advance_overhangs", coBools);
+    def->label = L("Enable adaptive pressure advance for overhangs (beta)");
+    def->tooltip = L("Enable adaptive PA for overhangs as well as when flow changes within the same feature. This is an experimental option, "
+                     "as if the PA profile is not set accurately, it will cause uniformity issues on the external surfaces before and after overhangs.\n");
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionBools{ false });
+    
+    def = this->add("adaptive_pressure_advance_bridges", coFloats);
+    def->label = L("Pressure advance for bridges");
+    def->tooltip = L("Pressure advance value for bridges. Set to 0 to disable. \n\n A lower PA value when printing bridges helps reduce the appearance of slight under extrusion "
+                     "immediately after bridges. This is caused by the pressure drop in the nozzle when printing in the air and a lower PA helps counteract this.");
+    def->max = 2;
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionFloats { 0.0 });
+
     def = this->add("line_width", coFloatOrPercent);
     def->label = L("Default");
     def->category = L("Quality");

src/libslic3r/PrintConfig.hpp

@@ -1031,6 +1031,12 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionFloats,              filament_flow_ratio))
     ((ConfigOptionBools,               enable_pressure_advance))
     ((ConfigOptionFloats,              pressure_advance))
+    // Orca: adaptive pressure advance and calibration model
+    ((ConfigOptionBools,                adaptive_pressure_advance))
+    ((ConfigOptionBools,                adaptive_pressure_advance_overhangs))
+    ((ConfigOptionStrings,             adaptive_pressure_advance_model))
+    ((ConfigOptionFloats,              adaptive_pressure_advance_bridges))
+    //
     ((ConfigOptionFloat,               fan_kickstart))
     ((ConfigOptionBool,                fan_speedup_overhangs))
     ((ConfigOptionFloat,               fan_speedup_time))

src/slic3r/GUI/Tab.cpp

@@ -3223,11 +3223,6 @@ void TabFilament::build()
         optgroup->append_single_option_line("required_nozzle_HRC");
         optgroup->append_single_option_line("default_filament_colour");
         optgroup->append_single_option_line("filament_diameter");
-        optgroup->append_single_option_line("pellet_flow_coefficient", "pellet-flow-coefficient");
-        optgroup->append_single_option_line("filament_flow_ratio");
-
-        optgroup->append_single_option_line("enable_pressure_advance");
-        optgroup->append_single_option_line("pressure_advance");
 
         optgroup->append_single_option_line("filament_density");
         optgroup->append_single_option_line("filament_shrink");
@@ -3249,6 +3244,25 @@ void TabFilament::build()
             on_value_change(opt_key, value);
         };
 
+        // Orca: New section to focus on flow rate and PA to declutter general section
+        optgroup = page->new_optgroup(L("Flow ratio and Pressure Advance"), L"param_information");
+        optgroup->append_single_option_line("pellet_flow_coefficient", "pellet-flow-coefficient");
+        optgroup->append_single_option_line("filament_flow_ratio");
+
+        optgroup->append_single_option_line("enable_pressure_advance");
+        optgroup->append_single_option_line("pressure_advance");
+
+        // Orca: adaptive pressure advance and calibration model
+        optgroup->append_single_option_line("adaptive_pressure_advance");
+        optgroup->append_single_option_line("adaptive_pressure_advance_overhangs");
+        optgroup->append_single_option_line("adaptive_pressure_advance_bridges");
+    
+        option = optgroup->get_option("adaptive_pressure_advance_model");
+        option.opt.full_width = true;
+        option.opt.is_code = true;
+        option.opt.height = 15;
+        optgroup->append_single_option_line(option);
+        //
 
         optgroup = page->new_optgroup(L("Print chamber temperature"), L"param_chamber_temp");
         optgroup->append_single_option_line("chamber_temperature", "chamber-temperature");
@@ -3539,8 +3553,17 @@ void TabFilament::toggle_options()
         toggle_line("eng_plate_temp_initial_layer", support_multi_bed_types);
         toggle_line("textured_plate_temp_initial_layer", support_multi_bed_types);
         
-        bool is_pellet_printer = cfg.opt_bool("pellet_modded_printer");
+        // Orca: adaptive pressure advance and calibration model
+        // If PA is not enabled, disable adaptive pressure advance and hide the model section
+        // If adaptive PA is not enabled, hide the adaptive PA model section
+        toggle_option("adaptive_pressure_advance", pa);
+        toggle_option("adaptive_pressure_advance_overhangs", pa);
+        bool has_adaptive_pa = m_config->opt_bool("adaptive_pressure_advance", 0);
+        toggle_line("adaptive_pressure_advance_overhangs", has_adaptive_pa && pa);
+        toggle_line("adaptive_pressure_advance_model", has_adaptive_pa && pa);
+        toggle_line("adaptive_pressure_advance_bridges", has_adaptive_pa && pa);
 
+        bool is_pellet_printer = cfg.opt_bool("pellet_modded_printer");
         toggle_line("pellet_flow_coefficient", is_pellet_printer);
         toggle_line("filament_diameter", !is_pellet_printer);
     }