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Improve Pressure Equalizer and fix related bugs #9622

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21 changes: 11 additions & 10 deletions src/libslic3r/GCode.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2860,8 +2860,7 @@ std::string GCode::_extrude(const ExtrusionPath &path, const std::string_view de
std::vector<ProcessedPoint> new_points{};
if (this->m_config.enable_dynamic_overhang_speeds && !this->on_first_layer() && path.role().is_perimeter()) {
new_points = m_extrusion_quality_estimator.estimate_extrusion_quality(path, m_config.overhang_overlap_levels,
m_config.dynamic_overhang_speeds,
m_config.get_abs_value("external_perimeter_speed"), speed);
m_config.dynamic_overhang_speeds, speed);
variable_speed = std::any_of(new_points.begin(), new_points.end(), [speed](const ProcessedPoint &p) { return p.speed != speed; });
}

Expand Down Expand Up @@ -2916,19 +2915,21 @@ std::string GCode::_extrude(const ExtrusionPath &path, const std::string_view de
+ float_to_string_decimal_point(m_last_height) + "\n";
}

std::string comment;
std::string cooling_marker_setspeed_comments;
if (m_enable_cooling_markers) {
if (path.role().is_bridge())
gcode += ";_BRIDGE_FAN_START\n";
else
comment = ";_EXTRUDE_SET_SPEED";
// NOTE: THIS TAG IS ALSO USED BY PRESSURE EQUALIZER
// so it knows which extrusions are eligible for flow modification
cooling_marker_setspeed_comments = ";_EXTRUDE_SET_SPEED";
if (path.role() == ExtrusionRole::ExternalPerimeter)
comment += ";_EXTERNAL_PERIMETER";
cooling_marker_setspeed_comments += ";_EXTERNAL_PERIMETER";
}

if (!variable_speed) {
// F is mm per minute.
gcode += m_writer.set_speed(F, "", comment);
gcode += m_writer.set_speed(F, "", cooling_marker_setspeed_comments);
double path_length = 0.;
std::string comment;
if (m_config.gcode_comments) {
Expand All @@ -2946,13 +2947,13 @@ std::string GCode::_extrude(const ExtrusionPath &path, const std::string_view de
prev = p;
}
} else {
std::string comment;
std::string comment = "";
if (m_config.gcode_comments) {
comment = description;
comment += description;
comment += description_bridge;
}
double last_set_speed = new_points[0].speed * 60.0;
gcode += m_writer.set_speed(last_set_speed, "", comment);
gcode += m_writer.set_speed(last_set_speed, "", cooling_marker_setspeed_comments);
Vec2d prev = this->point_to_gcode_quantized(new_points[0].p);
for (size_t i = 1; i < new_points.size(); i++) {
const ProcessedPoint& processed_point = new_points[i];
Expand All @@ -2962,7 +2963,7 @@ std::string GCode::_extrude(const ExtrusionPath &path, const std::string_view de
prev = p;
double new_speed = processed_point.speed * 60.0;
if (last_set_speed != new_speed) {
gcode += m_writer.set_speed(new_speed, "", comment);
gcode += m_writer.set_speed(new_speed, "", cooling_marker_setspeed_comments);
last_set_speed = new_speed;
}
}
Expand Down
3 changes: 1 addition & 2 deletions src/libslic3r/GCode/ExtrusionProcessor.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -260,14 +260,13 @@ class ExtrusionQualityEstimator
std::vector<ProcessedPoint> estimate_extrusion_quality(const ExtrusionPath &path,
const ConfigOptionPercents &overlaps,
const ConfigOptionFloatsOrPercents &speeds,
float ext_perimeter_speed,
float original_speed)
{
size_t speed_sections_count = std::min(overlaps.values.size(), speeds.values.size());
std::vector<std::pair<float, float>> speed_sections;
for (size_t i = 0; i < speed_sections_count; i++) {
float distance = path.width * (1.0 - (overlaps.get_at(i) / 100.0));
float speed = speeds.get_at(i).percent ? (ext_perimeter_speed * speeds.get_at(i).value / 100.0) : speeds.get_at(i).value;
float speed = speeds.get_at(i).percent ? (original_speed * speeds.get_at(i).value / 100.0) : speeds.get_at(i).value;
speed_sections.push_back({distance, speed});
}
std::sort(speed_sections.begin(), speed_sections.end(),
Expand Down
108 changes: 88 additions & 20 deletions src/libslic3r/GCode/PressureEqualizer.cpp
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
#include <memory.h>
#include <cstring>
#include <cfloat>
#include <algorithm>

#include "../libslic3r.h"
#include "../PrintConfig.hpp"
Expand All @@ -20,13 +21,19 @@ static const std::string EXTERNAL_PERIMETER_TAG = ";_EXTERNAL_PERIMETER";

// Maximum segment length to split a long segment if the initial and the final flow rate differ.
// Smaller value means a smoother transition between two different flow rates.
static constexpr float max_segment_length = 5.f;
static constexpr float max_segment_length = 1.f;

// For how many GCode lines back will adjust a flow rate from the latest line.
// Bigger values affect the GCode export speed a lot, and smaller values could
// affect how distant will be propagated a flow rate adjustment.
static constexpr int max_look_back_limit = 128;

// Max non-extruding XY distance (travel move) in mm between two continous extrusions where we pretend
// its all one continous extruded line. Above this distance we assume extruder pressure hits 0
// This exists because often there's tiny travel moves between stuff like infill
// lines where some extruder pressure will remain (so we should equalize between these small travels)
static constexpr long max_ignored_gap_between_extruding_segments = 3;

PressureEqualizer::PressureEqualizer(const Slic3r::GCodeConfig &config) : m_use_relative_e_distances(config.use_relative_e_distances.value)
{
// Preallocate some data, so that output_buffer.data() will return an empty string.
Expand Down Expand Up @@ -59,8 +66,8 @@ PressureEqualizer::PressureEqualizer(const Slic3r::GCodeConfig &config) : m_use_
extrusion_rate_slope.positive = m_max_volumetric_extrusion_rate_slope_positive;
}

// Don't regulate the pressure before and after gap-fill and ironing.
for (const GCodeExtrusionRole er : {GCodeExtrusionRole::GapFill, GCodeExtrusionRole::Ironing}) {
// Don't regulate the pressure before and after ironing.
for (const GCodeExtrusionRole er : {GCodeExtrusionRole::Ironing}) {
m_max_volumetric_extrusion_rate_slopes[size_t(er)].negative = 0;
m_max_volumetric_extrusion_rate_slopes[size_t(er)].positive = 0;
}
Expand Down Expand Up @@ -97,8 +104,71 @@ void PressureEqualizer::process_layer(const std::string &gcode)
}
assert(!this->opened_extrude_set_speed_block);
}

// at this point, we have an entire layer of gcode lines loaded into m_gcode_lines
// now we will split the mix of travels and extrudes into segments of continous extrusion and process those
// We skip over large travels, and pretend small ones are part of a continous extrusion segment
long idx_end_current_extrusion = 0;
while (idx_end_current_extrusion < m_gcode_lines.size()) {
// find beginning of next extrusion segment from current pos
const long idx_begin_current_extrusion = find_if(m_gcode_lines.begin() + idx_end_current_extrusion, m_gcode_lines.end(),
[](GCodeLine line) { return line.extruding(); }) - m_gcode_lines.begin();
// (extrusion begin idx = extrusion end idx) here because we start with extrusion length of zero
idx_end_current_extrusion = idx_begin_current_extrusion;

// inner loop extends the extrusion segment over small travel moves
while (idx_end_current_extrusion < m_gcode_lines.size()) {
// find end of the current extrusion segment
const auto just_after_end_extrusion = find_if(m_gcode_lines.begin() + idx_end_current_extrusion, m_gcode_lines.end(),
[](GCodeLine line) { return !line.extruding(); });
idx_end_current_extrusion = std::max<long>(0,(just_after_end_extrusion - m_gcode_lines.begin()) - 1);
const long idx_begin_segment_continuation = advance_segment_beyond_small_gap(idx_end_current_extrusion);
if (idx_begin_segment_continuation > idx_end_current_extrusion) {
// extend the continous line over the small gap
idx_end_current_extrusion = idx_begin_segment_continuation;
continue; // keep going, loop again to find new end of extrusion segment
} else {
// gap to next extrude is too big, stop looking forward. We've found end of this segment
break;
}
}

// now run the pressure equalizer across the segment like a streamroller
// it operates on a sliding window that moves forward across gcode line by line
for (int i = idx_begin_current_extrusion; i < idx_end_current_extrusion; ++i) {
// feed pressure equalizer past lines, going back to max_look_back_limit (or start of segment)
const auto start_idx = std::max<long>(idx_begin_current_extrusion, i - max_look_back_limit);
adjust_volumetric_rate(start_idx, i);
}
// current extrusion is all done processing so advance beyond it for next loop
idx_end_current_extrusion++;
}
}


long PressureEqualizer::advance_segment_beyond_small_gap(const long idx_orig)
{
// this should only be run on the last extruding line before a gap
assert(m_gcode_lines[idx_cur_pos].extruding());
double distance_traveled = 0.0;
// start at beginning of gap, advance till extrusion found or gap too big
for (auto idx_cur_pos = idx_orig + 1; idx_cur_pos < m_gcode_lines.size(); idx_cur_pos++) {
// started extruding again! return segment extension
if (m_gcode_lines[idx_cur_pos].extruding()) {
return idx_cur_pos;
}

distance_traveled += m_gcode_lines[idx_cur_pos].dist_xy();
// gap too big, dont extend segment
if (distance_traveled > max_ignored_gap_between_extruding_segments) {
return idx_orig;
}
}
// looped until end of layer and couldn't extend extrusion
return idx_orig;
}


LayerResult PressureEqualizer::process_layer(LayerResult &&input)
{
const bool is_first_layer = m_layer_results.empty();
Expand Down Expand Up @@ -390,8 +460,6 @@ bool PressureEqualizer::process_line(const char *line, const char *line_end, GCo

buf.extruder_id = m_current_extruder;
memcpy(buf.pos_end, m_current_pos, sizeof(float)*5);

adjust_volumetric_rate();
#ifdef PRESSURE_EQUALIZER_DEBUG
++line_idx;
#endif
Expand Down Expand Up @@ -506,14 +574,12 @@ void PressureEqualizer::output_gcode_line(const size_t line_idx)
}
}

void PressureEqualizer::adjust_volumetric_rate()
void PressureEqualizer::adjust_volumetric_rate(const size_t fist_line_idx, const size_t last_line_idx)
{
if (m_gcode_lines.size() < 2)
// don't bother adjusting volumetric rate if there's no gcode to adjust
if (last_line_idx-fist_line_idx < 2)
return;

// Go back from the current circular_buffer_pos and lower the feedtrate to decrease the slope of the extrusion rate changes.
size_t fist_line_idx = size_t(std::max<int>(0, int(m_gcode_lines.size()) - max_look_back_limit));
const size_t last_line_idx = m_gcode_lines.size() - 1;
size_t line_idx = last_line_idx;
if (line_idx == fist_line_idx || !m_gcode_lines[line_idx].extruding())
// Nothing to do, the last move is not extruding.
Expand All @@ -528,8 +594,8 @@ void PressureEqualizer::adjust_volumetric_rate()
for (; !m_gcode_lines[idx_prev].extruding() && idx_prev != fist_line_idx; --idx_prev);
if (!m_gcode_lines[idx_prev].extruding())
break;
// Don't decelerate before ironing and gap-fill.
if (m_gcode_lines[line_idx].extrusion_role == GCodeExtrusionRole::Ironing || m_gcode_lines[line_idx].extrusion_role == GCodeExtrusionRole::GapFill) {
// Don't decelerate before ironing.
if (m_gcode_lines[line_idx].extrusion_role == GCodeExtrusionRole::Ironing) {
line_idx = idx_prev;
continue;
}
Expand All @@ -549,7 +615,8 @@ void PressureEqualizer::adjust_volumetric_rate()
// Limit by the succeeding volumetric flow rate.
rate_end = rate_succ;

if (!line.adjustable_flow || line.extrusion_role == GCodeExtrusionRole::ExternalPerimeter || line.extrusion_role == GCodeExtrusionRole::GapFill || line.extrusion_role == GCodeExtrusionRole::BridgeInfill || line.extrusion_role == GCodeExtrusionRole::Ironing) {
// don't alter the flow rate for these extrusion types
if (!line.adjustable_flow || line.extrusion_role == GCodeExtrusionRole::BridgeInfill || line.extrusion_role == GCodeExtrusionRole::Ironing) {
rate_end = line.volumetric_extrusion_rate_end;
} else if (line.volumetric_extrusion_rate_end > rate_end) {
line.volumetric_extrusion_rate_end = rate_end;
Expand All @@ -572,8 +639,8 @@ void PressureEqualizer::adjust_volumetric_rate()
}
}
// feedrate_per_extrusion_role[iRole] = (iRole == line.extrusion_role) ? line.volumetric_extrusion_rate_start : rate_start;
// Don't store feed rate for ironing and gap-fill.
if (line.extrusion_role != GCodeExtrusionRole::Ironing && line.extrusion_role != GCodeExtrusionRole::GapFill)
// Don't store feed rate for ironing
if (line.extrusion_role != GCodeExtrusionRole::Ironing)
feedrate_per_extrusion_role[iRole] = line.volumetric_extrusion_rate_start;
}
}
Expand All @@ -587,8 +654,8 @@ void PressureEqualizer::adjust_volumetric_rate()
for (; !m_gcode_lines[idx_next].extruding() && idx_next != last_line_idx; ++idx_next);
if (!m_gcode_lines[idx_next].extruding())
break;
// Don't accelerate after ironing and gap-fill.
if (m_gcode_lines[line_idx].extrusion_role == GCodeExtrusionRole::Ironing || m_gcode_lines[line_idx].extrusion_role == GCodeExtrusionRole::GapFill) {
// Don't accelerate after ironing.
if (m_gcode_lines[line_idx].extrusion_role == GCodeExtrusionRole::Ironing) {
line_idx = idx_next;
continue;
}
Expand All @@ -603,7 +670,8 @@ void PressureEqualizer::adjust_volumetric_rate()
continue; // The positive rate is unlimited or the rate for GCodeExtrusionRole iRole is unlimited.

float rate_start = feedrate_per_extrusion_role[iRole];
if (!line.adjustable_flow || line.extrusion_role == GCodeExtrusionRole::ExternalPerimeter || line.extrusion_role == GCodeExtrusionRole::GapFill || line.extrusion_role == GCodeExtrusionRole::BridgeInfill || line.extrusion_role == GCodeExtrusionRole::Ironing) {
// don't alter the flow rate for these extrusion types
if (!line.adjustable_flow || line.extrusion_role == GCodeExtrusionRole::BridgeInfill || line.extrusion_role == GCodeExtrusionRole::Ironing) {
rate_start = line.volumetric_extrusion_rate_start;
} else if (iRole == size_t(line.extrusion_role) && rate_prec < rate_start)
rate_start = rate_prec;
Expand All @@ -628,8 +696,8 @@ void PressureEqualizer::adjust_volumetric_rate()
}
}
// feedrate_per_extrusion_role[iRole] = (iRole == line.extrusion_role) ? line.volumetric_extrusion_rate_end : rate_end;
// Don't store feed rate for ironing and gap-fill.
if (line.extrusion_role != GCodeExtrusionRole::Ironing && line.extrusion_role != GCodeExtrusionRole::GapFill)
// Don't store feed rate for ironing
if (line.extrusion_role != GCodeExtrusionRole::Ironing)
feedrate_per_extrusion_role[iRole] = line.volumetric_extrusion_rate_end;
}
}
Expand Down
3 changes: 2 additions & 1 deletion src/libslic3r/GCode/PressureEqualizer.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -180,11 +180,12 @@ class PressureEqualizer
#endif

bool process_line(const char *line, const char *line_end, GCodeLine &buf);
long advance_segment_beyond_small_gap(long idx_cur_pos);
void output_gcode_line(size_t line_idx);

// Go back from the current circular_buffer_pos and lower the feedtrate to decrease the slope of the extrusion rate changes.
// Then go forward and adjust the feedrate to decrease the slope of the extrusion rate changes.
void adjust_volumetric_rate();
void adjust_volumetric_rate(size_t first_line_idx, size_t last_line_idx);

// Push the text to the end of the output_buffer.
inline void push_to_output(GCodeG1Formatter &formatter);
Expand Down