Fan Speed Delay + Fan Kickstart Feature (#910)

Initial commit for fan speed delay, required some changes when porting from SuperSlicer.

Co-authored-by: SoftFever <softfeverever@gmail.com>

src/libslic3r/CMakeLists.txt

@@ -119,6 +119,8 @@ set(lisbslic3r_sources
     GCode/ThumbnailData.hpp
     GCode/CoolingBuffer.cpp
     GCode/CoolingBuffer.hpp
+	GCode/FanMover.cpp
+    GCode/FanMover.hpp
     GCode/PostProcessor.cpp
     GCode/PostProcessor.hpp
 #    GCode/PressureEqualizer.cpp

src/libslic3r/GCode.cpp

@@ -1443,6 +1443,8 @@ void GCode::_do_export(Print& print, GCodeOutputStream &file, ThumbnailsGenerato
 #if ENABLE_GCODE_VIEWER_DATA_CHECKING
     m_last_mm3_per_mm = 0.;
 #endif // ENABLE_GCODE_VIEWER_DATA_CHECKING
+
+    m_fan_mover.release();
     
     m_writer.set_is_bbl_machine(is_bbl_printers);
 
@@ -1810,6 +1812,10 @@ void GCode::_do_export(Print& print, GCodeOutputStream &file, ThumbnailsGenerato
     m_writer.set_current_position_clear(false);
     m_start_gcode_filament = GCodeProcessor::get_gcode_last_filament(machine_start_gcode);
 
+    //flush FanMover buffer to avoid modifying the start gcode if it's manual.
+    if (!machine_start_gcode.empty() && this->m_fan_mover.get() != nullptr)
+        file.write(this->m_fan_mover.get()->process_gcode("", true));
+
     // Process filament-specific gcode.
    /* if (has_wipe_tower) {
         // Wipe tower will control the extruder switching, it will call the filament_start_gcode.
@@ -2186,11 +2192,30 @@ void GCode::process_layers(
         [&output_stream](std::string s) { output_stream.write(s); }
     );
 
+    const auto fan_mover = tbb::make_filter<std::string, std::string>(slic3r_tbb_filtermode::serial_in_order,
+            [&fan_mover = this->m_fan_mover, &config = this->config(), &writer = this->m_writer](std::string in)->std::string {
+        CNumericLocalesSetter locales_setter;
+
+        if (config.fan_speedup_time.value != 0 || config.fan_kickstart.value > 0) {
+            if (fan_mover.get() == nullptr)
+                fan_mover.reset(new Slic3r::FanMover(
+                    writer,
+                    std::abs((float)config.fan_speedup_time.value),
+                    config.fan_speedup_time.value > 0,
+                    config.use_relative_e_distances.value,
+                    config.fan_speedup_overhangs.value,
+                    (float)config.fan_kickstart.value));
+            //flush as it's a whole layer
+            return fan_mover->process_gcode(in, true);
+        }
+        return in;
+    });
+
     // The pipeline elements are joined using const references, thus no copying is performed.
     if (m_spiral_vase)
-        tbb::parallel_pipeline(12, generator & spiral_mode & cooling & output);
+        tbb::parallel_pipeline(12, generator & spiral_mode & cooling & fan_mover & output);
     else
-        tbb::parallel_pipeline(12, generator & cooling & output);
+        tbb::parallel_pipeline(12, generator & cooling & fan_mover & output);
 }
 
 // Process all layers of a single object instance (sequential mode) with a parallel pipeline:
@@ -2234,11 +2259,29 @@ void GCode::process_layers(
         [&output_stream](std::string s) { output_stream.write(s); }
     );
 
+    const auto fan_mover = tbb::make_filter<std::string, std::string>(slic3r_tbb_filtermode::serial_in_order,
+        [&fan_mover = this->m_fan_mover, &config = this->config(), &writer = this->m_writer](std::string in)->std::string {
+
+        if (config.fan_speedup_time.value != 0 || config.fan_kickstart.value > 0) {
+            if (fan_mover.get() == nullptr)
+                fan_mover.reset(new Slic3r::FanMover(
+                    writer,
+                    std::abs((float)config.fan_speedup_time.value),
+                    config.fan_speedup_time.value > 0,
+                    config.use_relative_e_distances.value,
+                    config.fan_speedup_overhangs.value,
+                    (float)config.fan_kickstart.value));
+            //flush as it's a whole layer
+            return fan_mover->process_gcode(in, true);
+        }
+        return in;
+    });
+
     // The pipeline elements are joined using const references, thus no copying is performed.
     if (m_spiral_vase)
-        tbb::parallel_pipeline(12, generator & spiral_mode & cooling & output);
+        tbb::parallel_pipeline(12, generator & spiral_mode & cooling & fan_mover & output);
     else
-        tbb::parallel_pipeline(12, generator & cooling & output);
+        tbb::parallel_pipeline(12, generator & cooling & fan_mover & output);
 }
 
 std::string GCode::placeholder_parser_process(const std::string &name, const std::string &templ, unsigned int current_extruder_id, const DynamicConfig *config_override)

src/libslic3r/GCode.hpp

@@ -10,6 +10,7 @@
 #include "PrintConfig.hpp"
 #include "GCode/AvoidCrossingPerimeters.hpp"
 #include "GCode/CoolingBuffer.hpp"
+#include "GCode/FanMover.hpp"
 #include "GCode/RetractWhenCrossingPerimeters.hpp"
 #include "GCode/SpiralVase.hpp"
 #include "GCode/ToolOrdering.hpp"
@@ -491,6 +492,9 @@ private:
     // Processor
     GCodeProcessor m_processor;
 
+    //some post-processing on the file, with their data class
+    std::unique_ptr<FanMover> m_fan_mover;
+
     // BBS
     Print* m_curr_print = nullptr;
     unsigned int m_toolchange_count;

src/libslic3r/GCode/FanMover.cpp

@@ -0,0 +1,500 @@
+#include "FanMover.hpp"
+
+#include "GCodeReader.hpp"
+
+#include <iomanip>
+/*
+#include <memory.h>
+#include <string.h>
+#include <float.h>
+
+#include "../libslic3r.h"
+#include "../PrintConfig.hpp"
+#include "../Utils.hpp"
+#include "Print.hpp"
+
+#include <boost/log/trivial.hpp>
+*/
+
+
+namespace Slic3r {
+
+const std::string& FanMover::process_gcode(const std::string& gcode, bool flush)
+{
+    m_process_output = "";
+
+    // recompute buffer time to recover from rounding
+    m_buffer_time_size = 0;
+    for (auto& data : m_buffer) m_buffer_time_size += data.time;
+
+    if(!gcode.empty())
+        m_parser.parse_buffer(gcode,
+            [this](GCodeReader& reader, const GCodeReader::GCodeLine& line) { /*m_process_output += line.raw() + "\n";*/ this->_process_gcode_line(reader, line); });
+
+    if (flush) {
+        while (!m_buffer.empty()) {
+            m_process_output += m_buffer.front().raw + "\n";
+            remove_from_buffer(m_buffer.begin());
+        }
+    }
+
+    return m_process_output;
+}
+
+bool is_end_of_word(char c) {
+   return c == ' ' || c == '\t' || c == '\r' || c == '\n' || c == 0;
+}
+
+float get_axis_value(const std::string& line, char axis)
+{
+    char match[3] = " X";
+    match[1] = axis;
+
+    size_t pos = line.find(match) + 2;
+    //size_t end = std::min(line.find(' ', pos + 1), line.find(';', pos + 1));
+    // Try to parse the numeric value.
+    const char* c = line.c_str();
+    char* pend = nullptr;
+    errno = 0;
+    double  v = strtod(c + pos, &pend);
+    if (pend != nullptr && errno == 0 && pend != c) {
+        // The axis value has been parsed correctly.
+        return float(v);
+    }
+    return NAN;
+}
+
+void change_axis_value(std::string& line, char axis, const float new_value, const int decimal_digits)
+{
+
+    std::ostringstream ss;
+    ss << std::fixed << std::setprecision(decimal_digits) << new_value;
+
+    char match[3] = " X";
+    match[1] = axis;
+
+    size_t pos = line.find(match) + 2;
+    size_t end = std::min(line.find(' ', pos + 1), line.find(';', pos + 1));
+    line = line.replace(pos, end - pos, ss.str());
+}
+
+int16_t get_fan_speed(const std::string &line, GCodeFlavor flavor) {
+    if (line.compare(0, 4, "M106") == 0) {
+        if (flavor == (gcfMach3) || flavor == (gcfMachinekit)) {
+            return (int16_t)get_axis_value(line, 'P');
+        } else {
+            return (int16_t)get_axis_value(line, 'S');
+        }
+    } else if (line.compare(0, 4, "M127") == 0 || line.compare(0, 4, "M107") == 0) {
+        return 0;
+    } else if ((flavor == (gcfMakerWare) || flavor == (gcfSailfish)) && line.compare(0, 4, "M126") == 0) {
+        return (int16_t)get_axis_value(line, 'T');
+    } else {
+        return -1;
+    }
+
+}
+
+void FanMover::_put_in_middle_G1(std::list<BufferData>::iterator item_to_split, float nb_sec_since_itemtosplit_start, BufferData &&line_to_write) {
+    assert(item_to_split != m_buffer.end());
+    if (nb_sec_since_itemtosplit_start > item_to_split->time * 0.9) {
+        // doesn't really need to be split, print it after
+        m_buffer.insert(next(item_to_split), line_to_write);
+    } else if (nb_sec_since_itemtosplit_start < item_to_split->time * 0.1) {
+        // doesn't really need to be split, print it before
+        //will also print before if line_to_split.time == 0
+        m_buffer.insert(item_to_split, line_to_write);
+    } else if (item_to_split->raw.size() > 2
+        && item_to_split->raw[0] == 'G' && item_to_split->raw[1] == '1' && item_to_split->raw[2] == ' ') {
+        float percent = nb_sec_since_itemtosplit_start / item_to_split->time;
+        BufferData before = *item_to_split;
+        before.time *= percent;
+        item_to_split->time *= (1-percent);
+        if (item_to_split->dx != 0) {
+            before.dx = item_to_split->dx * percent;
+            item_to_split->x += before.dx;
+            item_to_split->dx = item_to_split->dx * (1-percent);
+            change_axis_value(before.raw, 'X', before.x + before.dx, 3);
+        }
+        if (item_to_split->dy != 0) {
+            before.dy = item_to_split->dy * percent;
+            item_to_split->y += before.dy;
+            item_to_split->dy = item_to_split->dy * (1 - percent);
+            change_axis_value(before.raw, 'Y', before.y + before.dy, 3);
+        }
+        if (item_to_split->dz != 0) {
+            before.dz = item_to_split->dz * percent;
+            item_to_split->z += before.dz;
+            item_to_split->dz = item_to_split->dz * (1 - percent);
+            change_axis_value(before.raw, 'Z', before.z + before.dz, 3);
+        }
+        if (item_to_split->de != 0) {
+            if (relative_e) {
+                before.de = item_to_split->de * percent;
+                change_axis_value(before.raw, 'E', before.de, 5);
+                item_to_split->de = item_to_split->de * (1 - percent);
+                change_axis_value(item_to_split->raw, 'E', item_to_split->de, 5);
+            } else {
+                before.de = item_to_split->de * percent;
+                item_to_split->e += before.de;
+                item_to_split->de = item_to_split->de * (1 - percent);
+                change_axis_value(before.raw, 'E', before.e + before.de, 5);
+            }
+        }
+        //add before then line_to_write, then there is the modified data.
+        m_buffer.insert(item_to_split, before);
+        m_buffer.insert(item_to_split, line_to_write);
+
+    } else {
+        //not a G1, print it before
+        m_buffer.insert(item_to_split, line_to_write);
+    }
+}
+
+void FanMover::_print_in_middle_G1(BufferData& line_to_split, float nb_sec, const std::string &line_to_write) {
+    if (nb_sec < line_to_split.time * 0.1) {
+        // doesn't really need to be split, print it after
+        m_process_output += line_to_split.raw + "\n";
+        m_process_output += line_to_write + (line_to_write.back() == '\n'?"":"\n");
+    } else if (nb_sec > line_to_split.time * 0.9) {
+        // doesn't really need to be split, print it before
+        //will also print before if line_to_split.time == 0
+        m_process_output += line_to_write + (line_to_write.back() == '\n' ? "" : "\n");
+        m_process_output += line_to_split.raw + "\n";
+    }else if(line_to_split.raw.size() > 2
+        && line_to_split.raw[0] == 'G' && line_to_split.raw[1] == '1' && line_to_split.raw[2] == ' ') {
+        float percent = nb_sec / line_to_split.time;
+        std::string before = line_to_split.raw;
+        std::string& after = line_to_split.raw;
+        if (line_to_split.dx != 0) {
+            change_axis_value(before, 'X', line_to_split.x + line_to_split.dx * percent, 3);
+        }
+        if (line_to_split.dy != 0) {
+            change_axis_value(before, 'Y', line_to_split.y + line_to_split.dy * percent, 3);
+        }
+        if (line_to_split.dz != 0) {
+            change_axis_value(before, 'Z', line_to_split.z + line_to_split.dz * percent, 3);
+        }
+        if (line_to_split.de != 0) {
+            if (relative_e) {
+                change_axis_value(before, 'E', line_to_split.de * percent, 5);
+                change_axis_value(after, 'E', line_to_split.de * (1 - percent), 5);
+            } else {
+                change_axis_value(before, 'E', line_to_split.e + line_to_split.de * percent, 5);
+            }
+        }
+        m_process_output += before + "\n";
+        m_process_output += line_to_write + (line_to_write.back() == '\n' ? "" : "\n");
+        m_process_output += line_to_split.raw + "\n";
+
+    } else {
+        //not a G1, print it before
+        m_process_output += line_to_write + (line_to_write.back() == '\n' ? "" : "\n");
+        m_process_output += line_to_split.raw + "\n";
+    }
+}
+
+void FanMover::_remove_slow_fan(int16_t min_speed, float past_sec) {
+    //erase fan in the buffer -> don't slowdown if you are in the process of step-up.
+    //we began at the "recent" side , and remove as long as we don't push past_sec to 0
+    auto it = m_buffer.begin();
+    while (it != m_buffer.end() && past_sec > 0) {
+        past_sec -= it->time;
+        if (it->fan_speed >= 0 && it->fan_speed < min_speed){
+            //found something that is lower than us
+            it = remove_from_buffer(it);
+
+        } else {
+            ++it;
+        }
+    }
+
+}
+
+std::string FanMover::_set_fan(int16_t speed) {
+    //const Tool* tool = m_writer.get_tool(m_currrent_extruder < 20 ? m_currrent_extruder : 0);
+    return GCodeWriter::set_fan(m_writer.config.gcode_flavor.value, speed);
+}
+
+
+bool parse_number(const std::string_view sv, int& out)
+{
+    {
+        // Legacy conversion, which is costly due to having to make a copy of the string before conversion.
+        try {
+            assert(sv.size() < 1024);
+            assert(sv.data() != nullptr);
+            std::string str{ sv };
+            size_t read = 0;
+            out = std::stoi(str, &read);
+            return str.size() == read;
+        }
+        catch (...) {
+            return false;
+        }
+    }
+}
+
+//FIXME: add other firmware
+// or just create that damn new gcode writer arch
+void FanMover::_process_T(const std::string_view command)
+{
+    if (command.length() > 1) {
+        int eid = 0;
+        if (!parse_number(command.substr(1), eid) || eid < 0 || eid > 255) {
+            GCodeFlavor flavor = m_writer.config.gcode_flavor;
+            // Specific to the MMU2 V2 (see https://www.help.prusa3d.com/en/article/prusa-specific-g-codes_112173):
+            if ((flavor == gcfMarlinLegacy || flavor == gcfMarlinFirmware) && (command == "Tx" || command == "Tc" || command == "T?"))
+                return;
+
+            // T-1 is a valid gcode line for RepRap Firmwares (used to deselects all tools) see https://github.com/prusa3d/PrusaSlicer/issues/5677
+            if ((flavor != gcfRepRapFirmware && flavor != gcfRepRapSprinter) || eid != -1)
+                m_currrent_extruder = static_cast<uint16_t>(0);
+        } else {
+            m_currrent_extruder = static_cast<uint16_t>(eid);
+        }
+    }
+}
+
+void FanMover::_process_gcode_line(GCodeReader& reader, const GCodeReader::GCodeLine& line)
+{
+    // processes 'normal' gcode lines
+    bool need_flush = false;
+    std::string cmd(line.cmd());
+    double time = 0;
+    int16_t fan_speed = -1;
+    if (cmd.length() > 1) {
+        if (line.has_f())
+            m_current_speed = line.f() / 60.0f;
+        switch (::toupper(cmd[0])) {
+        case 'T':
+        case 't':
+            _process_T(cmd);
+                break;
+        case 'G':
+        {
+            if (::atoi(&cmd[1]) == 1 || ::atoi(&cmd[1]) == 0) {
+                double distx = line.dist_X(reader);
+                double disty = line.dist_Y(reader);
+                double distz = line.dist_Z(reader);
+                double dist = distx * distx + disty * disty + distz * distz;
+                if (dist > 0) {
+                    dist = std::sqrt(dist);
+                    time = dist / m_current_speed;
+                }
+            }
+            break;
+        }
+        case 'M':
+        {
+            fan_speed = get_fan_speed(line.raw(), m_writer.config.gcode_flavor);
+            if (fan_speed >= 0) {
+                const auto fan_baseline = 255.0;
+                fan_speed = 100 * fan_speed / fan_baseline;
+                //speed change: stop kickstart reverting if any
+                m_current_kickstart.time = -1;
+                if (!m_is_custom_gcode) {
+                    // if slow down => put in the queue. if not =>
+                    if (m_back_buffer_fan_speed < fan_speed) {
+                        if (nb_seconds_delay > 0 && (!only_overhangs || current_role == ExtrusionRole::erOverhangPerimeter)) {
+                            //don't put this command in the queue
+                            time = -1;
+                            // this M106 need to go in the past
+                            //check if we have ( kickstart and not in slowdown )
+                            if (kickstart > 0 && fan_speed > m_front_buffer_fan_speed) {
+                                //stop current kickstart , it's not relevant anymore
+                                if (m_current_kickstart.time > 0) {
+                                    m_current_kickstart.time = (-1);
+                                }
+
+                                //if kickstart
+                                // first erase everything lower that that value
+                                _remove_slow_fan(fan_speed, m_buffer_time_size + 1);
+                                // then erase everything lower that kickstart
+                                _remove_slow_fan(fan_baseline, kickstart);
+                                // print me
+                                if (!m_buffer.empty() && (m_buffer_time_size - m_buffer.front().time * 0.1) > nb_seconds_delay) {
+                                    _print_in_middle_G1(m_buffer.front(), m_buffer_time_size - nb_seconds_delay, _set_fan(100));//m_writer.set_fan(100, true)); //FIXME extruder id (or use the gcode writer, but then you have to disable the multi-thread thing
+                                    remove_from_buffer(m_buffer.begin());
+                                } else {
+                                    m_process_output += _set_fan(100);//m_writer.set_fan(100, true)); //FIXME extruder id (or use the gcode writer, but then you have to disable the multi-thread thing
+                                }
+                                //write it in the queue if possible
+                                const float kickstart_duration = kickstart * float(fan_speed - m_front_buffer_fan_speed) / 100.f;
+                                float time_count = kickstart_duration;
+                                auto it = m_buffer.begin();
+                                while (it != m_buffer.end() && time_count > 0) {
+                                    time_count -= it->time;
+                                    if (time_count< 0) {
+                                        //found something that is lower than us
+                                        _put_in_middle_G1(it, it->time + time_count, BufferData(std::string(line.raw()), 0, fan_speed, true));
+                                        //found, stop
+                                        break;
+                                    }
+                                    ++it;
+                                }
+                                if (time_count > 0) {
+                                    //can't place it in the buffer, use m_current_kickstart
+                                    m_current_kickstart.fan_speed = fan_speed;
+                                    m_current_kickstart.time = time_count;
+                                    m_current_kickstart.raw = line.raw();
+                                }
+                                m_front_buffer_fan_speed = fan_speed;
+                            } else {
+                                // first erase everything lower that that value
+                                _remove_slow_fan(fan_speed, m_buffer_time_size + 1);
+                                // then write the fan command
+                                if (!m_buffer.empty() && (m_buffer_time_size - m_buffer.front().time * 0.1) > nb_seconds_delay) {
+                                    _print_in_middle_G1(m_buffer.front(), m_buffer_time_size - nb_seconds_delay, line.raw());
+                                    remove_from_buffer(m_buffer.begin());
+                                } else {
+                                    m_process_output += line.raw() + "\n";
+                                }
+                                m_front_buffer_fan_speed = fan_speed;
+                            }
+                        } else {
+                            if (kickstart <= 0) {
+                                //nothing to do
+                                //we don't put time = -1; so it will printed in the buffer as other line are done
+                            } else if (m_current_kickstart.time > 0) {
+                                //cherry-pick this one
+                                if (m_back_buffer_fan_speed >= fan_speed) {
+                                    //stop kickstart
+                                    m_current_kickstart.time = -1;
+                                    //this will print me just after as time >=0
+                                } else {
+                                    // add some duration to the kickstart and use it for me.
+                                    float kickstart_duration = kickstart * float(fan_speed - m_back_buffer_fan_speed) / 100.f;
+                                    m_current_kickstart.fan_speed = fan_speed;
+                                    m_current_kickstart.time += kickstart_duration;
+                                    m_current_kickstart.raw = line.raw();
+                                    //i'm printed by the m_current_kickstart
+                                    time = -1;
+                                }
+                            } else if(m_back_buffer_fan_speed < fan_speed - 10){ //only kickstart if more than 10% change
+                                //don't write this line, as it will need to be delayed
+                                time = -1;
+                                //get the duration of kickstart
+                                float kickstart_duration = kickstart * float(fan_speed - m_back_buffer_fan_speed) / 100.f;
+                                //if kickstart, write the M106 S[fan_baseline] first
+                                //set the target speed and set the kickstart flag
+                                put_in_buffer(BufferData(_set_fan(100)//m_writer.set_fan(100, true)); //FIXME extruder id (or use the gcode writer, but then you have to disable the multi-thread thing
+                                    , 0, fan_speed, true));
+                                //kickstart!
+                                //m_process_output += m_writer.set_fan(100, true);
+                                //add the normal speed line for the future
+                                m_current_kickstart.fan_speed = fan_speed;
+                                m_current_kickstart.time = kickstart_duration;
+                                m_current_kickstart.raw = line.raw();
+                            }
+                        }
+                    }
+                    //update back buffer fan speed
+                    m_back_buffer_fan_speed = fan_speed;
+                } else {
+                    // have to flush the buffer to avoid erasing a fan command.
+                    need_flush = true;
+                }
+            }
+            break;
+        }
+        }
+    } else {
+        if(!line.raw().empty() && line.raw().front() == ';')
+        {
+            if (line.raw().size() > 10 && line.raw().rfind(";TYPE:", 0) == 0) {
+                // get the type of the next extrusions
+                std::string extrusion_string = line.raw().substr(6, line.raw().size() - 6);
+                current_role = ExtrusionEntity::string_to_role(extrusion_string);
+            }
+            if (line.raw().size() > 16) {
+                if (line.raw().rfind("; custom gcode", 0) != std::string::npos)
+                    if (line.raw().rfind("; custom gcode end", 0) != std::string::npos)
+                        m_is_custom_gcode = false;
+                    else
+                        m_is_custom_gcode = true;
+            }
+        }
+    }
+
+    if (time >= 0) {
+        BufferData& new_data = put_in_buffer(BufferData(line.raw(), time, fan_speed));
+        if (line.has(Axis::X)) {
+            new_data.x = reader.x();
+            new_data.dx = line.dist_X(reader);
+        }
+        if (line.has(Axis::Y)) {
+            new_data.y = reader.y();
+            new_data.dy = line.dist_Y(reader);
+        }
+        if (line.has(Axis::Z)) {
+            new_data.z = reader.z();
+            new_data.dz = line.dist_Z(reader);
+        }
+        if (line.has(Axis::E)) {
+            new_data.e = reader.e();
+            if (relative_e)
+                new_data.de = line.e();
+            else
+                new_data.de = line.dist_E(reader);
+        }
+
+        if (m_current_kickstart.time > 0 && time > 0) {
+            m_current_kickstart.time -= time;
+            if (m_current_kickstart.time < 0) {
+                //prev is possible because we just do a emplace_back.
+                _put_in_middle_G1(prev(m_buffer.end()), time + m_current_kickstart.time, BufferData{ m_current_kickstart.raw, 0, m_current_kickstart.fan_speed, true });
+            }
+        }
+    }/* else {
+        BufferData& new_data = put_in_buffer(BufferData("; del? "+line.raw(), 0, fan_speed));
+        if (line.has(Axis::X)) {
+            new_data.x = reader.x();
+            new_data.dx = line.dist_X(reader);
+        }
+        if (line.has(Axis::Y)) {
+            new_data.y = reader.y();
+            new_data.dy = line.dist_Y(reader);
+        }
+        if (line.has(Axis::Z)) {
+            new_data.z = reader.z();
+            new_data.dz = line.dist_Z(reader);
+        }
+        if (line.has(Axis::E)) {
+            new_data.e = reader.e();
+            if (relative_e)
+                new_data.de = line.e();
+            else
+                new_data.de = line.dist_E(reader);
+        }
+    }*/
+    // puts the line back into the gcode
+    //if buffer too big, flush it.
+    if (time >= 0) {
+        while (!m_buffer.empty() && (need_flush || m_buffer_time_size - m_buffer.front().time > nb_seconds_delay - EPSILON) ){
+            BufferData& frontdata = m_buffer.front();
+            if (frontdata.fan_speed < 0 || frontdata.fan_speed != m_front_buffer_fan_speed || frontdata.is_kickstart) {
+                if (frontdata.is_kickstart && frontdata.fan_speed < m_front_buffer_fan_speed) {
+                    //you have to slow down! not kickstart! rewrite the fan speed.
+                    m_process_output += _set_fan(frontdata.fan_speed);//m_writer.set_fan(frontdata.fan_speed,true); //FIXME extruder id (or use the gcode writer, but then you have to disable the multi-thread thing
+                        
+                    m_front_buffer_fan_speed = frontdata.fan_speed;
+                } else {
+                    m_process_output += frontdata.raw + "\n";
+                    if (frontdata.fan_speed >= 0) {
+                        //note that this is the only place where the fan_speed is set and we print from the buffer, as if the fan_speed >= 0 => time == 0
+                        //and as this flush all time == 0 lines from the back of the queue...
+                        m_front_buffer_fan_speed = frontdata.fan_speed;
+                    }
+                }
+            }
+            remove_from_buffer(m_buffer.begin());
+        }
+    }
+    double sum = 0;
+    for (auto& data : m_buffer) sum += data.time;
+    assert( std::abs(m_buffer_time_size - sum) < 0.01);
+}
+
+} // namespace Slic3r
+

src/libslic3r/GCode/FanMover.hpp

@@ -0,0 +1,95 @@
+#ifndef slic3r_GCode_FanMover_hpp_
+#define slic3r_GCode_FanMover_hpp_
+
+
+#include "../libslic3r.h"
+#include "../PrintConfig.hpp"
+#include "../ExtrusionEntity.hpp"
+
+#include "../Point.hpp"
+#include "../GCodeReader.hpp"
+#include "../GCodeWriter.hpp"
+#include <regex>
+
+namespace Slic3r {
+
+class BufferData {
+public:
+    std::string raw;
+    float time;
+    int16_t fan_speed;
+    bool is_kickstart;
+    float x = 0, y = 0, z = 0, e = 0;
+    float dx = 0, dy = 0, dz = 0, de = 0;
+    BufferData(std::string line, float time = 0, int16_t fan_speed = 0, float is_kickstart = false) : raw(line), time(time), fan_speed(fan_speed), is_kickstart(is_kickstart){
+        //avoid double \n
+        if(!line.empty() && line.back() == '\n') line.pop_back();
+    }
+};
+
+class FanMover
+{
+private:
+    const std::regex regex_fan_speed;
+    const float nb_seconds_delay;
+    const bool with_D_option;
+    const bool relative_e;
+    const bool only_overhangs;
+    const float kickstart;
+
+    GCodeReader m_parser{};
+    const GCodeWriter& m_writer;
+
+    //current value (at the back of the buffer), when parsing a new line
+    ExtrusionRole current_role = ExtrusionRole::erCustom;
+    // in unit/second
+    double m_current_speed = 1000 / 60.0;
+    bool m_is_custom_gcode = false;
+    uint16_t m_currrent_extruder = 0;
+
+    // variable for when you add a line (front of the buffer)
+    int m_front_buffer_fan_speed = 0;
+    int m_back_buffer_fan_speed = 0;
+    BufferData m_current_kickstart{"",-1,0};
+
+    //buffer
+    std::list<BufferData> m_buffer;
+    double m_buffer_time_size = 0;
+
+    // The output of process_layer()
+    std::string m_process_output;
+
+public:
+    FanMover(const GCodeWriter& writer, const float nb_seconds_delay, const bool with_D_option, const bool relative_e,
+        const bool only_overhangs, const float kickstart)
+        : regex_fan_speed("S[0-9]+"), 
+        nb_seconds_delay(nb_seconds_delay>0 ? std::max(0.01f,nb_seconds_delay) : 0),
+        with_D_option(with_D_option)
+        , relative_e(relative_e), only_overhangs(only_overhangs), kickstart(kickstart), m_writer(writer){}
+
+    // Adds the gcode contained in the given string to the analysis and returns it after removing the workcodes
+    const std::string& process_gcode(const std::string& gcode, bool flush);
+
+private:
+    BufferData& put_in_buffer(BufferData&& data) {
+        m_buffer_time_size += data.time;
+        m_buffer.emplace_back(data);
+        return m_buffer.back();
+    }
+    std::list<BufferData>::iterator remove_from_buffer(std::list<BufferData>::iterator data) {
+        m_buffer_time_size -= data->time;
+        return m_buffer.erase(data);
+    }
+    // Processes the given gcode line
+    void _process_gcode_line(GCodeReader& reader, const GCodeReader::GCodeLine& line);
+    void _process_T(const std::string_view command);
+    void _put_in_middle_G1(std::list<BufferData>::iterator item_to_split, float nb_sec, BufferData&& line_to_write);
+    void _print_in_middle_G1(BufferData& line_to_split, float nb_sec, const std::string& line_to_write);
+    void _remove_slow_fan(int16_t min_speed, float past_sec);
+    std::string _set_fan(int16_t speed);
+};
+
+} // namespace Slic3r
+
+
+#endif /* slic3r_GCode_FanMover_hpp_ */

src/libslic3r/Preset.cpp

@@ -795,6 +795,7 @@ static std::vector<std::string> s_Preset_machine_limits_options {
 static std::vector<std::string> s_Preset_printer_options {
     "printer_technology",
     "printable_area", "bed_exclude_area","bed_custom_texture", "bed_custom_model", "gcode_flavor",
+    "fan_kickstart", "fan_speedup_time", "fan_speedup_overhangs",
     "single_extruder_multi_material", "machine_start_gcode", "machine_end_gcode", "before_layer_change_gcode", "layer_change_gcode", "change_filament_gcode",
     "printer_model", "printer_variant", "printable_height", "extruder_clearance_radius", "extruder_clearance_height_to_lid", "extruder_clearance_height_to_rod",
     "default_print_profile", "inherits",

src/libslic3r/Print.cpp

@@ -98,6 +98,9 @@ bool Print::invalidate_state_by_config_options(const ConfigOptionResolver & /* n
         "reduce_fan_stop_start_freq",
         "fan_cooling_layer_time",
         "full_fan_speed_layer",
+        "fan_kickstart",
+        "fan_speedup_overhangs",
+        "fan_speedup_time",
         "filament_colour",
         "default_filament_colour",
         "filament_diameter",

src/libslic3r/PrintConfig.cpp

@@ -1773,6 +1773,35 @@ void PrintConfigDef::init_fff_params()
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionBool(false));
 
+    def = this->add("fan_speedup_time", coFloat);
+    def->label = L("");
+    def->tooltip = L("Start the fan this number of seconds earlier than its target start time (you can use fractional seconds)."
+        " It assumes infinite acceleration for this time estimation, and will only take into account G1 and G0 moves (arc fitting"
+        " is unsupported)."
+        "\nIt won't move fan comands from custom gcodes (they act as a sort of 'barrier')."
+        "\nIt won't move fan comands into the start gcode if the 'only custom start gcode' is activated."
+        "\nUse 0 to deactivate.");
+    def->sidetext = L("s");
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionFloat(0));
+
+    def = this->add("fan_speedup_overhangs", coBool);
+    def->label = L("Only overhangs");
+    def->tooltip = L("Will only take into account the delay for the cooling of overhangs.");
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionBool(true));
+
+    def = this->add("fan_kickstart", coFloat);
+    def->label = L("Fan kick-start time");
+    def->tooltip = L("Emit a max fan speed command for this amount of seconds before reducing to target speed to kick-start the cooling fan."
+                    "\nThis is useful for fans where a low PWM/power may be insufficient to get the fan started spinning from a stop, or to "
+                    "get the fan up to speed faster."
+                    "\nSet to 0 to deactivate.");
+    def->sidetext = L("s");
+    def->min = 0;
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionFloat(0));
+
     def = this->add("gcode_flavor", coEnum);
     def->label = L("G-code flavor");
     def->tooltip = L("What kind of gcode the printer is compatible with");

src/libslic3r/PrintConfig.hpp

@@ -829,6 +829,9 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionFloats,              filament_flow_ratio))
     ((ConfigOptionBools,               enable_pressure_advance))
     ((ConfigOptionFloats,              pressure_advance))
+    ((ConfigOptionFloat,               fan_kickstart))
+    ((ConfigOptionBool,                fan_speedup_overhangs))
+    ((ConfigOptionFloat,               fan_speedup_time))
     ((ConfigOptionFloats,              filament_diameter))
     ((ConfigOptionFloats,              filament_density))
     ((ConfigOptionStrings,             filament_type))

src/slic3r/GUI/Tab.cpp

@@ -3093,6 +3093,13 @@ void TabPrinter::build_fff()
         optgroup->append_single_option_line("machine_load_filament_time");
         optgroup->append_single_option_line("machine_unload_filament_time");
 
+        optgroup = page->new_optgroup(L("Cooling Fan"));
+        Line line = Line{ L("Fan speedup time"), optgroup->get_option("fan_speedup_time").opt.tooltip };
+        line.append_option(optgroup->get_option("fan_speedup_time"));
+        line.append_option(optgroup->get_option("fan_speedup_overhangs"));
+        optgroup->append_line(line);
+        optgroup->append_single_option_line("fan_kickstart");
+
         optgroup = page->new_optgroup(L("Extruder Clearance"));
         optgroup->append_single_option_line("extruder_clearance_radius");
         optgroup->append_single_option_line("extruder_clearance_height_to_rod");