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Fix overhang slowdown and fan applied to whole walls ahead of an overhang (#15945)

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This commit is contained in:
Ioannis Giannakas
2026-09-28 10:59:39 +01:00
committed by GitHub
parent 3df9c215f8
commit 7707487252
3 changed files with 231 additions and 97 deletions
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src/libslic3r/GCode.cpp
+28 -23
View File
@@ -7969,6 +7969,20 @@ double GCode::calc_max_volumetric_speed(const double layer_height, const double
return res;
}
// ORCA: Overlap at or below which the overhang fan switches on; negative when it does not depend on overlap
// (Overhang_threshold_none cools every external perimeter).
static float overhang_fan_overlap_threshold(int overhang_fan_threshold)
{
switch (overhang_fan_threshold) {
case (int) Overhang_threshold_1_4: return 0.9f;
case (int) Overhang_threshold_2_4: return 0.75f;
case (int) Overhang_threshold_3_4: return 0.5f;
case (int) Overhang_threshold_4_4: return 0.25f;
case (int) Overhang_threshold_bridge: return 0.05f;
default: return -1.f;
}
}
std::string GCode::_extrude(const ExtrusionPath &path, std::string description, double speed)
{
std::string gcode;
@@ -8311,6 +8325,13 @@ std::string GCode::_extrude(const ExtrusionPath &path, std::string description,
ConfigOptionPercents overhang_overlap_levels({90, 75, 50, 25, 13, 0});
// ORCA: Lets the path be split where the overhang fan switches, not only where the speed changes.
// Bridges and overhang perimeters are cooled regardless of overlap.
float fan_overlap_threshold = -1.f;
if (FILAMENT_CONFIG(enable_overhang_bridge_fan) && m_enable_cooling_markers && path.role() != erBridgeInfill &&
path.role() != erOverhangPerimeter)
fan_overlap_threshold = overhang_fan_overlap_threshold(FILAMENT_CONFIG(overhang_fan_threshold));
if (NOZZLE_CONFIG(slowdown_for_curled_perimeters)){
ConfigOptionFloatsOrPercents dynamic_overhang_speeds(
{FloatOrPercent{100, true},
@@ -8331,7 +8352,8 @@ std::string GCode::_extrude(const ExtrusionPath &path, std::string description,
FloatOrPercent{NOZZLE_CONFIG(overhang_4_4_speed).get_abs_value(ref_speed) * 100 / ref_speed, true}});
new_points = m_extrusion_quality_estimator.estimate_extrusion_quality(path, overhang_overlap_levels, dynamic_overhang_speeds,
ref_speed, speed, NOZZLE_CONFIG(slowdown_for_curled_perimeters));
ref_speed, speed, NOZZLE_CONFIG(slowdown_for_curled_perimeters),
fan_overlap_threshold);
}else{
ConfigOptionFloatsOrPercents dynamic_overhang_speeds(
{FloatOrPercent{100, true},
@@ -8350,7 +8372,8 @@ std::string GCode::_extrude(const ExtrusionPath &path, std::string description,
FloatOrPercent{NOZZLE_CONFIG(bridge_speed) * 100 / ref_speed, true}});
new_points = m_extrusion_quality_estimator.estimate_extrusion_quality(path, overhang_overlap_levels, dynamic_overhang_speeds,
ref_speed, speed, NOZZLE_CONFIG(slowdown_for_curled_perimeters));
ref_speed, speed, NOZZLE_CONFIG(slowdown_for_curled_perimeters),
fan_overlap_threshold);
}
variable_speed = std::any_of(new_points.begin(), new_points.end(),
[speed](const ProcessedPoint &p) { return fabs(double(p.speed) - speed) > 1; }); // Ignore small speed variations (under 1mm/sec)
@@ -8502,28 +8525,10 @@ std::string GCode::_extrude(const ExtrusionPath &path, std::string description,
if (role == erBridgeInfill || role == erOverhangPerimeter) { // ORCA: Split out bridge infill to internal and external to apply separate fan settings
return true;
}
switch (overhang_fan_threshold) {
case (int)Overhang_threshold_1_4:
return overlap <= 0.9f;
break;
case (int)Overhang_threshold_2_4:
return overlap <= 0.75f;
break;
case (int)Overhang_threshold_3_4:
return overlap <= 0.5f;
break;
case (int)Overhang_threshold_4_4:
return overlap <= 0.25f;
break;
case (int)Overhang_threshold_bridge:
return overlap <= 0.05f;
break;
case (int)Overhang_threshold_none:
if (overhang_fan_threshold == Overhang_threshold_none)
return is_external_perimeter(role);
break;
default:
return false;
}
const float overlap_threshold = overhang_fan_overlap_threshold(overhang_fan_threshold);
return overlap_threshold >= 0.f && overlap <= overlap_threshold;
};
std::string comment;
src/libslic3r/GCode/ExtrusionProcessor.hpp
+110 -74
View File
@@ -41,10 +41,12 @@ std::vector<ExtendedPoint<L::Dim>> estimate_points_properties(const POINTS&
float flow_width,
float max_line_length = -1.0f,
float min_distance = -1.0f,
// Maps an overhang distance onto the speed it will be printed at. Interior sampling
// needs it to tell which of the points it could add would change the G-code, and is
// skipped without it.
const std::function<float(float)>& distance_to_speed = {})
// Speed an overhang distance prints at. Without it, interior sampling
// is skipped and every line over 4mm is split.
const std::function<float(float)>& distance_to_speed = {},
// Overlap (1 - distance / flow_width) at or below which the overhang
// fan switches on; negative when the fan does not depend on overlap.
float fan_overlap_threshold = -1.0f)
{
bool looped = input_points.front() == input_points.back();
std::function<size_t(size_t,size_t)> get_prev_index = [](size_t idx, size_t count) {
@@ -125,29 +127,43 @@ std::vector<ExtendedPoint<L::Dim>> estimate_points_properties(const POINTS&
points.push_back(next_point);
}
// ORCA: How an overhang distance prints, which is what the passes below compare. A segment is printed at the lower
// of the speeds at its two ends, and with the overhang fan on if the overlap at either end turns it on. A point
// added to a path can therefore only change the G-code where it prints at a different speed or fan state from the
// points either side of it, and the passes below add points there and nowhere else.
const float width_inv = 1.f / flow_width;
// Whether an overhang distance turns the overhang fan on. The overlap test check_overhang_fan applies in GCode.cpp.
auto fan_on = [fan_overlap_threshold, width_inv](float distance) {
return fan_overlap_threshold >= 0.f && 1.f - distance * width_inv <= fan_overlap_threshold;
};
// Whether two overhang distances are interchangeable ie have the same speed (beyond a 1mm/sec threshold that gcode.cpp filters out on)
// and the same fan state.
auto same_speed_and_fan = [&distance_to_speed, &fan_on](float a, float b) {
return std::abs(distance_to_speed(a) - distance_to_speed(b)) <= 1.f && fan_on(a) == fan_on(b);
};
// Whether the first overhang distance prints slower than the second, beyond the 1mm/sec gcode.cpp tolerance, or turns the overhang
// fan on where the second does not. Against a supported point (overhang distance 0) it tells whether an end is
// affected by the overhang.
auto slower_or_cooled = [&distance_to_speed, &fan_on](float a, float b) {
return distance_to_speed(a) < distance_to_speed(b) - 1.f || (fan_on(a) && !fan_on(b));
};
// ORCA: Interior sampling
// The passes below infer the support under a span from its endpoints alone, so an interior that is supported
// differently from both ends is invisible to them: the outer perimeter of an overhang whose ends are caged by
// full height walls reads as supported along its whole length. Probe the interior, keep the samples the
// endpoint interpolation fails to predict, and bisect either side of each one, so a span that is only partly
// unsupported gets points where its support actually changes instead of one reading spread across all of it.
if (PREV_LAYER_BOUNDARY_OFFSET && ADD_INTERSECTIONS && min_distance > 0 && distance_to_speed) {
// The passes below infer the support under a span from its endpoints alone, so a part that is supported
// differently from both ends is invisible to them. The outer perimeter of an overhang whose ends are supported by
// reads as supported along its whole length. Probe the interior, keep the samples the endpoint interpolation fails to predict,
// and bisect either side of each one, so a span that is only partly unsupported gets points where its support actually changes
// instead of one reading being spread across all of it.
// Skipped where there is nothing to find: min_distance <= 0 when no overhang can slow this path down, and
// fan_overlap_threshold < 0 when no overhang switches the fan on. It also needs distance_to_speed to tell which of
// the points it could add would change the G-code.
if (PREV_LAYER_BOUNDARY_OFFSET && ADD_INTERSECTIONS && distance_to_speed && (min_distance > 0 || fan_overlap_threshold >= 0.f)) {
// Probe at least this densely before treating matching samples as evidence that a span is uniform. The
// segmentation pass below only splits lines of 2mm or more, and every pass here drops points closer
// together than min_spacing, so finer discovery would not produce a more precise speed transition.
// together than min_spacing, so finer discovery would not produce a more precise transition.
const double max_probe_spacing = std::max(2., 4. * min_spacing);
// A backstop for that length test, which on a non-finite length would never be met.
constexpr int max_bisection_depth = 10;
// Whether two readings are interchangeable. A segment is printed at the lower of the speeds its ends
// read, so a sample that agrees on speed with what is already known cannot change the G-code, whatever
// its distance says. The distances themselves are far too coarse a stand-in for this: the speed sections
// interpolate, so readings a small fraction of min_distance apart can still be tens of mm/s apart.
// The tolerance matches the one GCode.cpp applies when it decides a path has a variable speed at all.
auto same_speed = [&distance_to_speed](float a, float b) {
return std::abs(distance_to_speed(a) - distance_to_speed(b)) <= 1.f;
};
// Whether the first reading is printed slower than the second, once they are known to differ.
auto prints_slower = [&distance_to_speed](float a, float b) { return distance_to_speed(a) < distance_to_speed(b); };
// Part of a segment still to bisect: its positions along the segment and bisections left.
struct Subspan { double t0, t1; int depth; };
@@ -185,8 +201,8 @@ std::vector<ExtendedPoint<L::Dim>> estimate_points_properties(const POINTS&
if (!interior.empty()) {
std::sort(interior.begin(), interior.end(),
[](const std::pair<double, float>& l, const std::pair<double, float>& r) { return l.first < r.first; });
// Coarse probing keeps every sample it took until this pass can see which ones bracket a speed
// transition. Matching samples cannot be discarded during discovery: one may be the last
// Coarse probing keeps every sample it took until this pass can see which ones bracket a speed or
// fan transition. Matching samples cannot be discarded during discovery: one may be the last
// supported point before a narrow unsupported pocket found by a later probe.
size_t kept = 0;
for (size_t i = 0; i < interior.size(); ++i) {
@@ -195,15 +211,15 @@ std::vector<ExtendedPoint<L::Dim>> estimate_points_properties(const POINTS&
const bool at_end = i + 1 == interior.size(); // And nothing follows the last sample but the segment's end
const float before = at_start ? curr.distance : interior[kept - 1].second;
const float after = at_end ? next.distance : interior[i + 1].second;
// A sample is worth a point in the path only where it prints at a different speed from the
// readings either side of it. Differing from one of the segment's own ends is not enough on
// its own where the sample is the faster of the two: the segmentation pass below already
// ends the slowdown an end reads, at a distance taken from how far out that end is rather
// than from wherever bisection happened to stop, and a point here would leave the span
// beside the end too short for that pass to run at all. Support an end cannot account for,
// where the interior is the slower reading, is exactly what this pass is here to find.
const bool worth_before = !same_speed(sample, before) && (!at_start || prints_slower(sample, before));
const bool worth_after = !same_speed(sample, after) && (!at_end || prints_slower(sample, after));
// A sample is worth a point in the path only where it prints differently, in speed or fan state,
// from the points either side of it. Differing from one of the segment's own ends is not enough on
// its own where the sample is not the slower or cooled of the two: the segmentation pass below
// already confines the slowdown and cooling at an end, at a distance taken from how far out that
// end is rather than from wherever bisection happened to stop, and a point here would leave the
// span beside the end too short for that pass to run at all. Support an end cannot account for,
// where the interior is the slower or cooled of the two, is exactly what this pass is here to find.
const bool worth_before = !same_speed_and_fan(sample, before) && (!at_start || slower_or_cooled(sample, before));
const bool worth_after = !same_speed_and_fan(sample, after) && (!at_end || slower_or_cooled(sample, after));
if (worth_before || worth_after)
interior[kept++] = interior[i];
}
@@ -238,52 +254,60 @@ std::vector<ExtendedPoint<L::Dim>> estimate_points_properties(const POINTS&
if ((curr.distance > -boundary_offset && curr.distance < boundary_offset + 2.0f) ||
(next.distance > -boundary_offset && next.distance < boundary_offset + 2.0f)) {
double line_len = (next.position - curr.position).norm();
// ORCA: Segment path to smaller lines by adding additional points only if the path has an overhang that
// will trigger a slowdown and the path is also reasonably large, i.e. 2mm in length or more
// If there is no overhang in the start/end point, dont segment it.
// Ignore this check if the control of segmentation for overhangs is disabled (min_distance=-1)
if ((min_distance > 0 && ((std::abs(curr.distance) > min_distance) || (std::abs(next.distance) > min_distance)) && line_len >= 2.f) ||
(min_distance <= 0 && line_len > 4.0f)) {
// ORCA: A line prints as slow as its slower end and is cooled if either end is, so an overhang at one
// end would otherwise slow down or cool the whole line. Split the line so that only the part beside
// that end prints that way, if the line is reasonably long (2mm or more) and at least one end prints
// slower or cooled compared with a supported point (overhang distance 0). Deciding on how the end
// prints, rather than on its overhang distance against min_distance, also catches an end whose overhang
// distance is exactly where the slowdown begins, such as an outline crossing at half a line width.
// Without distance_to_speed, split every line over 4mm.
const bool split_line = distance_to_speed ?
line_len >= 2.f && (slower_or_cooled(curr.distance, 0.f) || slower_or_cooled(next.distance, 0.f)) :
line_len > 4.0f;
if (split_line) {
// Each end's piece is that end's overhang distance plus 1.5 line widths (3 * boundary_offset) long:
// a0 ends the piece beside curr, a1 starts the piece beside next.
double a0 = std::clamp((curr.distance + 3 * boundary_offset) / line_len, 0.0, 1.0);
double a1 = std::clamp(1.0f - (next.distance + 3 * boundary_offset) / line_len, 0.0, 1.0);
double t0 = std::min(a0, a1);
double t1 = std::max(a0, a1);
if (t0 < 1.0) {
Vec p0 = curr.position + t0 * (next.position - curr.position);
auto [p0_dist, p0_near_l, p0_x] = unscaled_prev_layer.template distance_from_lines_extra<SIGNED_DISTANCE>(
p0.template cast<AABBScalar>());
ExtendedPoint<L::Dim> new_p{};
new_p.position = p0;
new_p.distance = float(p0_dist + boundary_offset);
// ORCA: only create a new point in the path if the new point overhang distance will be used to generate a speed change
// or if this option is disabled (min_distance<=0)
if( (std::abs(p0_dist) > min_distance) || (min_distance<=0)){
// ORCA: also filter out points that are introduced to the start of the path when their distance from the start point is
// not meaningful
if ((p0 - curr.position).norm() > min_spacing && (next.position - p0).norm() > min_spacing) {
new_points.push_back(new_p);
}
}
// Up to two cut points, in order along the line. Each takes its own overhang distance, so every
// piece prints by the overhang distances at its own two ends. t0 >= 1 or t1 <= 0 falls on the
// line's own end, so there is no cut. A cut closer than min_spacing to either end of the line is
// not meaningful and is filtered out (#6714).
ExtendedPoint<L::Dim> cut[2]{};
bool keep[2] = {false, false};
for (int k = 0; k < 2; ++k) {
const double t = k == 0 ? t0 : t1;
if (k == 0 ? t >= 1.0 : t <= 0.0)
continue;
const Vec p = curr.position + t * (next.position - curr.position);
auto [p_dist, p_near_l, p_x] = unscaled_prev_layer.template distance_from_lines_extra<SIGNED_DISTANCE>(
p.template cast<AABBScalar>());
cut[k].position = p;
cut[k].distance = float(p_dist + boundary_offset);
keep[k] = (p - curr.position).norm() > min_spacing && (next.position - p).norm() > min_spacing;
}
if (t1 > 0.0) {
Vec p1 = curr.position + t1 * (next.position - curr.position);
auto [p1_dist, p1_near_l, p1_x] = unscaled_prev_layer.template distance_from_lines_extra<SIGNED_DISTANCE>(
p1.template cast<AABBScalar>());
ExtendedPoint<L::Dim> new_p{};
new_p.position = p1;
new_p.distance = float(p1_dist + boundary_offset);
// ORCA: only create a new point in the path if the new point overhang distance will be used to generate a speed change
// or if this option is disabled (min_distance<=0)
if( (std::abs(p1_dist) > min_distance) || (min_distance<=0)){
// ORCA: filter out points that are introduced to the end of the path when their distance from the end point is
// not meaningful
if ((p1 - curr.position).norm() > min_spacing && (next.position - p1).norm() > min_spacing) {
new_points.push_back(new_p);
}
}
if (distance_to_speed) {
// Only keep a cut that changes the G-code: one that prints differently from at least one of the
// points either side of it, which are the line's ends or the other cut where that is kept. A cut
// that prints like both would only split a move into two identical ones.
if (keep[0])
keep[0] = !same_speed_and_fan(cut[0].distance, curr.distance) ||
!same_speed_and_fan(cut[0].distance, keep[1] ? cut[1].distance : next.distance);
if (keep[1])
keep[1] = !same_speed_and_fan(cut[1].distance, keep[0] ? cut[0].distance : curr.distance) ||
!same_speed_and_fan(cut[1].distance, next.distance);
// Two cuts closer together than min_spacing would leave a micro segment between them, so only the
// first is kept.
if (keep[0] && keep[1] && (cut[1].position - cut[0].position).norm() <= min_spacing)
keep[1] = false;
}
for (int k = 0; k < 2; ++k)
if (keep[k])
new_points.push_back(cut[k]);
}
}
new_points.push_back(next);
@@ -423,7 +447,10 @@ public:
const ConfigOptionFloatsOrPercents &speeds,
float ext_perimeter_speed,
float original_speed,
bool slowdown_for_curled_edges)
bool slowdown_for_curled_edges,
// Overlap at or below which the overhang fan switches on; negative when the fan
// does not depend on overlap.
float fan_overlap_threshold = -1.0f)
{
size_t speed_sections_count = std::min(overlaps.values.size(), speeds.values.size());
std::vector<std::pair<float, float>> speed_sections;
@@ -463,7 +490,8 @@ public:
}
}
// If a meaningful (i.e. needing slowdown) overhang distance was not found, then we shouldn't split the lines
// If no overhang distance slows this path down, -1 turns interior sampling off unless the overhang fan can switch.
// Lines are only split where an end prints slower or cooled, so here only a fan switch splits them.
if (!found)
smallest_distance_with_lower_speed=-1.f;
@@ -487,9 +515,17 @@ public:
return round(final_speed);
};
// ORCA: The speed sections are built from ext_perimeter_speed, which can be above the speed this path prints at
// (original_speed, e.g. held down by resonance avoidance). Every segment is capped at original_speed below, so
// overhang distances whose speeds differ only above it print the same and must not count as a speed change when
// the path is split.
auto effective_speed = [&calculate_speed, original_speed](float distance) {
return std::min(calculate_speed(distance), original_speed);
};
std::vector<ExtendedPoint<3>> extended_points =
estimate_points_properties<true, true, true, true>(path.polyline.points, prev_layer_boundaries[current_object], path.width, -1,
smallest_distance_with_lower_speed, calculate_speed);
smallest_distance_with_lower_speed, effective_speed, fan_overlap_threshold);
const auto width_inv = 1.0f / path.width;
std::vector<ProcessedPoint> processed_points;
processed_points.reserve(extended_points.size());