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Merge branch 'pm_seam_curling_fix_250' into master_250

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This commit is contained in:
Lukas Matena 2022-07-14 18:07:39 +02:00
commit 04555862b0
3 changed files with 121 additions and 109 deletions
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206
src/libslic3r/GCode/SeamPlacer.cpp
View File

@ -64,6 +64,16 @@ float gauss(float value, float mean_x_coord, float mean_value, float falloff_spe
return mean_value * (std::exp(exponent) - 1.0f) / (std::exp(1.0f) - 1.0f);
}
float compute_angle_penalty(float ccw_angle) {
// This function is used:
// ((ℯ^(((1)/(x^(2)*3+1)))-1)/(ℯ-1))*1+((1)/(2+ℯ^(-x)))
// looks scary, but it is gaussian combined with sigmoid,
// so that concave points have much smaller penalty over convex ones
// https://github.com/prusa3d/PrusaSlicer/tree/master/doc/seam_placement/corner_penalty_function.png
return gauss(ccw_angle, 0.0f, 1.0f, 3.0f) +
1.0f / (2 + std::exp(-ccw_angle));
}
/// Coordinate frame
class Frame {
public:
@ -457,22 +467,41 @@ Polygons extract_perimeter_polygons(const Layer *layer, const SeamPosition confi
//each SeamCandidate also contains pointer to shared Perimeter structure representing the polygon
// if Custom Seam modifiers are present, oversamples the polygon if necessary to better fit user intentions
void process_perimeter_polygon(const Polygon &orig_polygon, float z_coord, const LayerRegion *region,
const GlobalModelInfo &global_model_info, PrintObjectSeamData::LayerSeams &result) {
bool arachne_generated, const GlobalModelInfo &global_model_info, PrintObjectSeamData::LayerSeams &result) {
if (orig_polygon.size() == 0) {
return;
}
Polygon polygon = orig_polygon;
bool was_clockwise = polygon.make_counter_clockwise();
std::vector<float> lengths { };
for (size_t point_idx = 0; point_idx < polygon.size() - 1; ++point_idx) {
lengths.push_back((unscale(polygon[point_idx]) - unscale(polygon[point_idx + 1])).norm());
}
lengths.push_back(std::max((unscale(polygon[0]) - unscale(polygon[polygon.size() - 1])).norm(), 0.1));
bool was_clockwise = polygon.make_counter_clockwise();
std::vector<float> local_angles = calculate_polygon_angles_at_vertices(polygon, lengths,
std::vector<float> polygon_angles = calculate_polygon_angles_at_vertices(polygon, lengths,
SeamPlacer::polygon_local_angles_arm_distance);
// resample smooth surfaces from arachne, so that alignment finds short path down, and does not create unnecesary curves
if (arachne_generated && std::all_of(polygon_angles.begin(), polygon_angles.end(), [](float angle) {
return compute_angle_penalty(angle) > SeamPlacer::sharp_angle_penalty_snapping_threshold;
})) {
float total_dist = std::accumulate(lengths.begin(), lengths.end(), 0.0f);
float avg_dist = total_dist / float(lengths.size());
if (avg_dist < SeamPlacer::seam_align_tolerable_dist * 2.0f){
coord_t sampling_dist = scaled(avg_dist*0.2f);
polygon.points = polygon.equally_spaced_points(sampling_dist);
lengths.clear();
for (size_t point_idx = 0; point_idx < polygon.size() - 1; ++point_idx) {
lengths.push_back((unscale(polygon[point_idx]) - unscale(polygon[point_idx + 1])).norm());
}
lengths.push_back(std::max((unscale(polygon[0]) - unscale(polygon[polygon.size() - 1])).norm(), 0.1));
polygon_angles = calculate_polygon_angles_at_vertices(polygon, lengths, avg_dist);
}
}
result.perimeters.push_back( { });
Perimeter &perimeter = result.perimeters.back();
@ -498,16 +527,16 @@ void process_perimeter_polygon(const Polygon &orig_polygon, float z_coord, const
} else {
position = orig_polygon_points.front();
orig_polygon_points.pop();
local_ccw_angle = was_clockwise ? -local_angles[orig_angle_index] : local_angles[orig_angle_index];
local_ccw_angle = was_clockwise ? -polygon_angles[orig_angle_index] : polygon_angles[orig_angle_index];
orig_angle_index++;
orig_point = true;
}
if (global_model_info.is_enforced(position, SeamPlacer::enforcer_blocker_distance_tolerance)) {
if (global_model_info.is_enforced(position, perimeter.flow_width)) {
type = EnforcedBlockedSeamPoint::Enforced;
}
if (global_model_info.is_blocked(position, SeamPlacer::enforcer_blocker_distance_tolerance)) {
if (global_model_info.is_blocked(position, perimeter.flow_width)) {
type = EnforcedBlockedSeamPoint::Blocked;
}
some_point_enforced = some_point_enforced || type == EnforcedBlockedSeamPoint::Enforced;
@ -560,7 +589,8 @@ void process_perimeter_polygon(const Polygon &orig_polygon, float z_coord, const
break;
}
viable_points_indices.push_back(last_enforced_idx);
if (abs(result.points[last_enforced_idx].local_ccw_angle) > SeamPlacer::sharp_angle_snapping_threshold) {
if (compute_angle_penalty(result.points[last_enforced_idx].local_ccw_angle)
< SeamPlacer::sharp_angle_penalty_snapping_threshold) {
orig_large_angle_points_indices.push_back(last_enforced_idx);
}
last_enforced_idx = next_index(last_enforced_idx);
@ -827,17 +857,10 @@ struct SeamComparator {
return is_first_not_much_worse(a, b) && is_first_not_much_worse(b, a);
}
float compute_angle_penalty(float ccw_angle) const {
// This function is used:
// ((ℯ^(((1)/(x^(2)*3+1)))-1)/(ℯ-1))*1+((1)/(2+ℯ^(-x)))
// looks scary, but it is gaussian combined with sigmoid,
// so that concave points have much smaller penalty over convex ones
// https://github.com/prusa3d/PrusaSlicer/tree/master/doc/seam_placement/corner_penalty_function.png
return gauss(ccw_angle, 0.0f, 1.0f, 3.0f) +
1.0f / (2 + std::exp(-ccw_angle));
}
float weight(const SeamCandidate &a) const {
if (setup == SeamPosition::spAligned && a.central_enforcer) {
return 2.0f;
}
return a.visibility + angle_importance * compute_angle_penalty(a.local_ccw_angle) / (1.0f + angle_importance);
}
};
@ -1046,12 +1069,14 @@ public:
void SeamPlacer::gather_seam_candidates(const PrintObject *po,
const SeamPlacerImpl::GlobalModelInfo &global_model_info, const SeamPosition configured_seam_preference) {
using namespace SeamPlacerImpl;
bool arachne_generated = po->config().perimeter_generator == PerimeterGeneratorType::Arachne;
PrintObjectSeamData &seam_data = m_seam_per_object.emplace(po, PrintObjectSeamData { }).first->second;
seam_data.layers.resize(po->layer_count());
tbb::parallel_for(tbb::blocked_range<size_t>(0, po->layers().size()),
[po, configured_seam_preference, &global_model_info, &seam_data](tbb::blocked_range<size_t> r) {
[po, configured_seam_preference, arachne_generated, &global_model_info, &seam_data]
(tbb::blocked_range<size_t> r) {
for (size_t layer_idx = r.begin(); layer_idx < r.end(); ++layer_idx) {
PrintObjectSeamData::LayerSeams &layer_seams = seam_data.layers[layer_idx];
const Layer *layer = po->get_layer(layer_idx);
@ -1061,7 +1086,7 @@ void SeamPlacer::gather_seam_candidates(const PrintObject *po,
Polygons polygons = extract_perimeter_polygons(layer, configured_seam_preference, regions);
for (size_t poly_index = 0; poly_index < polygons.size(); ++poly_index) {
process_perimeter_polygon(polygons[poly_index], unscaled_z,
regions[poly_index], global_model_info, layer_seams);
regions[poly_index], arachne_generated, global_model_info, layer_seams);
}
auto functor = SeamCandidateCoordinateFunctor { layer_seams.points };
seam_data.layers[layer_idx].points_tree =
@ -1135,16 +1160,12 @@ void SeamPlacer::calculate_overhangs_and_layer_embedding(const PrintObject *po)
// Used by align_seam_points().
std::optional<std::pair<size_t, size_t>> SeamPlacer::find_next_seam_in_layer(
const std::vector<PrintObjectSeamData::LayerSeams> &layers,
const std::pair<size_t, size_t> &prev_point_index,
const size_t layer_idx, const float slice_z,
const Vec3f& projected_position,
const size_t layer_idx, const float max_distance,
const SeamPlacerImpl::SeamComparator &comparator) const {
using namespace SeamPlacerImpl;
const SeamCandidate &last_point = layers[prev_point_index.first].points[prev_point_index.second];
Vec3f projected_position { last_point.position.x(), last_point.position.y(), slice_z };
std::vector<size_t> nearby_points_indices = find_nearby_points(*layers[layer_idx].points_tree, projected_position,
SeamPlacer::seam_align_tolerable_dist);
max_distance);
if (nearby_points_indices.empty()) {
return {};
@ -1185,7 +1206,7 @@ std::optional<std::pair<size_t, size_t>> SeamPlacer::find_next_seam_in_layer(
// First try to pick central enforcer if any present
if (next_layer_seam.central_enforcer
&& (next_layer_seam.position - projected_position).squaredNorm()
< sqr(3 * SeamPlacer::seam_align_tolerable_dist)) {
< sqr(3 * max_distance)) {
return {std::pair<size_t, size_t> {layer_idx, nearest_point.perimeter.seam_index}};
}
@ -1203,69 +1224,60 @@ std::optional<std::pair<size_t, size_t>> SeamPlacer::find_next_seam_in_layer(
std::vector<std::pair<size_t, size_t>> SeamPlacer::find_seam_string(const PrintObject *po,
std::pair<size_t, size_t> start_seam, const SeamPlacerImpl::SeamComparator &comparator,
std::optional<std::pair<size_t, size_t>> &out_best_moved_seam, size_t &out_moved_seams_count) const {
out_best_moved_seam.reset();
out_moved_seams_count = 0;
float& string_weight) const {
string_weight = 0.0f;
const std::vector<PrintObjectSeamData::LayerSeams> &layers = m_seam_per_object.find(po)->second.layers;
int layer_idx = start_seam.first;
int seam_index = start_seam.second;
//initialize searching for seam string - cluster of nearby seams on previous and next layers
int next_layer = layer_idx + 1;
int step = 1;
std::pair<size_t, size_t> prev_point_index = start_seam;
std::vector<std::pair<size_t, size_t>> seam_string { start_seam };
//find seams or potential seams in forward direction; there is a budget of skips allowed
while (next_layer < int(layers.size())) {
auto maybe_next_seam = find_next_seam_in_layer(layers, prev_point_index, next_layer,
float(po->get_layer(next_layer)->slice_z), comparator);
if (maybe_next_seam.has_value()) {
auto reverse_lookup_direction = [&]() {
step = -1;
prev_point_index = start_seam;
next_layer = layer_idx - 1;
};
while (next_layer >= 0) {
if (next_layer >= int(layers.size())) {
reverse_lookup_direction();
if (next_layer < 0) {
break;
}
}
float max_distance = SeamPlacer::seam_align_tolerable_dist;
Vec3f prev_position = layers[prev_point_index.first].points[prev_point_index.second].position;
Vec3f projected_position = prev_position;
projected_position.z() = float(po->get_layer(next_layer)->slice_z);
std::optional<std::pair<size_t, size_t>> maybe_next_seam = find_next_seam_in_layer(layers, projected_position,
next_layer,
max_distance, comparator);
if (maybe_next_seam.has_value()) {
// For old macOS (pre 10.14), std::optional does not have .value() method, so the code is using operator*() instead.
std::pair<size_t, size_t> next_seam_coords = maybe_next_seam.operator*();
const auto &next_seam = layers[next_seam_coords.first].points[next_seam_coords.second];
bool is_moved = next_seam.perimeter.seam_index != next_seam_coords.second;
out_moved_seams_count += is_moved;
if (is_moved && (!out_best_moved_seam.has_value() ||
comparator.is_first_better(next_seam,
layers[out_best_moved_seam.operator*().first].points[out_best_moved_seam.operator*().second]))) {
out_best_moved_seam = { next_seam_coords };
}
string_weight += comparator.weight(next_seam) -
is_moved ? comparator.weight(layers[next_seam_coords.first].points[next_seam.perimeter.seam_index]) : 0.0f;
seam_string.push_back(maybe_next_seam.operator*());
prev_point_index = seam_string.back();
//String added, prev_point_index updated
} else {
break;
}
next_layer++;
}
//do additional check in back direction
next_layer = layer_idx - 1;
prev_point_index = std::pair<size_t, size_t>(layer_idx, seam_index);
while (next_layer >= 0) {
auto maybe_next_seam = find_next_seam_in_layer(layers, prev_point_index, next_layer,
float(po->get_layer(next_layer)->slice_z), comparator);
if (maybe_next_seam.has_value()) {
std::pair<size_t, size_t> next_seam_coords = maybe_next_seam.operator*();
const auto &next_seam = layers[next_seam_coords.first].points[next_seam_coords.second];
bool is_moved = next_seam.perimeter.seam_index != next_seam_coords.second;
out_moved_seams_count += is_moved;
if (is_moved && (!out_best_moved_seam.has_value() ||
comparator.is_first_better(next_seam,
layers[out_best_moved_seam.operator*().first].points[out_best_moved_seam.operator*().second]))) {
out_best_moved_seam = { next_seam_coords };
if (step == 1) {
reverse_lookup_direction();
if (next_layer < 0) {
break;
}
} else {
break;
}
seam_string.push_back(maybe_next_seam.operator*());
prev_point_index = seam_string.back();
//String added, prev_point_index updated
} else {
break;
}
next_layer--;
next_layer += step;
}
return seam_string;
@ -1311,7 +1323,7 @@ void SeamPlacer::align_seam_points(const PrintObject *po, const SeamPlacerImpl::
}
//sort them before alignment. Alignment is sensitive to initializaion, this gives it better chance to choose something nice
std::sort(seams.begin(), seams.end(),
std::stable_sort(seams.begin(), seams.end(),
[&comparator, &layers](const std::pair<size_t, size_t> &left,
const std::pair<size_t, size_t> &right) {
return comparator.is_first_better(layers[left.first].points[left.second],
@ -1337,22 +1349,21 @@ void SeamPlacer::align_seam_points(const PrintObject *po, const SeamPlacerImpl::
// This perimeter is already aligned, skip seam
continue;
} else {
std::optional<std::pair<size_t, size_t>> best_moved_seam;
size_t moved_seams_count;
seam_string = this->find_seam_string(po, { layer_idx, seam_index }, comparator, best_moved_seam,
moved_seams_count);
if (best_moved_seam.has_value()) {
size_t alternative_moved_seams_count;
alternative_seam_string = this->find_seam_string(po, best_moved_seam.operator*(), comparator,
best_moved_seam, alternative_moved_seams_count);
float seam_string_weight;
seam_string = this->find_seam_string(po, { layer_idx, seam_index }, comparator, seam_string_weight);
size_t step_size = 1 + seam_string.size() / 20;
for (size_t alternative_start = 0; alternative_start < seam_string.size(); alternative_start+=step_size) {
float alternative_seam_string_weight = 0;
size_t start_layer_idx = seam_string[alternative_start].first;
size_t seam_idx = layers[start_layer_idx].points[seam_string[alternative_start].second].perimeter.seam_index;
alternative_seam_string = this->find_seam_string(po, std::pair<size_t,size_t>(start_layer_idx, seam_idx), comparator,
alternative_seam_string_weight);
if (alternative_seam_string.size() >= SeamPlacer::seam_align_minimum_string_seams &&
alternative_moved_seams_count < moved_seams_count) {
alternative_seam_string_weight > seam_string_weight) {
seam_string_weight = alternative_seam_string_weight;
seam_string = std::move(alternative_seam_string);
// finish loop. but repeat the alignment for the current seam, since it could be skipped due to alternative path being aligned.
global_index--;
}
}
if (seam_string.size() < seam_align_minimum_string_seams) {
//string NOT long enough to be worth aligning, skip
continue;
@ -1365,26 +1376,29 @@ void SeamPlacer::align_seam_points(const PrintObject *po, const SeamPlacerImpl::
return left.first < right.first;
});
//repeat the alignment for the current seam, since it could be skipped due to alternative path being aligned.
global_index--;
// gather all positions of seams and their weights (weights are derived as negative penalty, they are made positive in next step)
observations.resize(seam_string.size());
observation_points.resize(seam_string.size());
weights.resize(seam_string.size());
//gather points positions and weights
// The algorithm uses only angle to compute penalty, to enforce snapping to sharp corners, if they are present
// after several experiments approach that gives best results is to snap the weight to one for sharp corners, and
// leave it small for others. However, this can result in non-smooth line over area with a lot of unaligned sharp corners.
float total_length = 0.0f;
Vec3f last_point_pos = layers[seam_string[0].first].points[seam_string[0].second].position;
for (size_t index = 0; index < seam_string.size(); ++index) {
Vec3f pos = layers[seam_string[index].first].points[seam_string[index].second].position;
total_length += (last_point_pos - pos).norm();
last_point_pos = pos;
observations[index] = pos.head<2>();
observation_points[index] = pos.z();
weights[index] = std::min(1.0f,
comparator.weight(layers[seam_string[index].first].points[seam_string[index].second]));
weights[index] = comparator.weight(layers[seam_string[index].first].points[seam_string[index].second]);
}
// Curve Fitting
size_t number_of_segments = std::max(size_t(1),
size_t(observations.size() / SeamPlacer::seam_align_seams_per_segment));
size_t(total_length / SeamPlacer::seam_align_mm_per_segment));
auto curve = Geometry::fit_cubic_bspline(observations, observation_points, weights, number_of_segments);
// Do alignment - compute fitted point for each point in the string from its Z coord, and store the position into
@ -1392,14 +1406,14 @@ void SeamPlacer::align_seam_points(const PrintObject *po, const SeamPlacerImpl::
for (size_t index = 0; index < seam_string.size(); ++index) {
const auto &pair = seam_string[index];
const float t =
abs(layers[pair.first].points[pair.second].local_ccw_angle)
> SeamPlacer::sharp_angle_snapping_threshold
? 1.0 : 0.0f;
compute_angle_penalty(layers[pair.first].points[pair.second].local_ccw_angle)
< SeamPlacer::sharp_angle_penalty_snapping_threshold
? 0.8f : 0.0f;
Vec3f current_pos = layers[pair.first].points[pair.second].position;
Vec2f fitted_pos = curve.get_fitted_value(current_pos.z());
//interpolate between current and fitted position, prefer current pos for large weights.
Vec3f final_position = t * current_pos + (1 - t) * to_3d(fitted_pos, current_pos.z());
Vec3f final_position = t * current_pos + (1.0f - t) * to_3d(fitted_pos, current_pos.z());
Perimeter &perimeter = layers[pair.first].points[pair.second].perimeter;
perimeter.seam_index = pair.second;

20
src/libslic3r/GCode/SeamPlacer.hpp
View File

@ -128,17 +128,16 @@ public:
// arm length used during angles computation
static constexpr float polygon_local_angles_arm_distance = 0.3f;
static constexpr float sharp_angle_snapping_threshold = 0.3f * float(PI);
// value for angles with penalty lower than this threshold - such angles will be snapped to their original position instead of spline interpolated position
static constexpr float sharp_angle_penalty_snapping_threshold = 0.6f;
// max tolerable distance from the previous layer is overhang_distance_tolerance_factor * flow_width
static constexpr float overhang_distance_tolerance_factor = 0.5f;
// determines angle importance compared to visibility ( neutral value is 1.0f. )
static constexpr float angle_importance_aligned = 0.6f;
static constexpr float angle_importance_nearest = 1.0f; // use much higher angle importance for nearest mode, to combat the visiblity info noise
static constexpr float angle_importance_nearest = 1.0f; // use much higher angle importance for nearest mode, to combat the visibility info noise
// If enforcer or blocker is closer to the seam candidate than this limit, the seam candidate is set to Blocker or Enforcer
static constexpr float enforcer_blocker_distance_tolerance = 0.35f;
// For long polygon sides, if they are close to the custom seam drawings, they are oversampled with this step size
static constexpr float enforcer_oversampling_distance = 0.2f;
@ -148,9 +147,9 @@ public:
// seam_align_tolerable_dist - if next layer closest point is too far away, break aligned string
static constexpr float seam_align_tolerable_dist = 1.0f;
// minimum number of seams needed in cluster to make alignment happen
static constexpr size_t seam_align_minimum_string_seams = 10;
// points covered by spline; determines number of splines for the given string
static constexpr size_t seam_align_seams_per_segment = 16;
static constexpr size_t seam_align_minimum_string_seams = 6;
// millimeters covered by spline; determines number of splines for the given string
static constexpr size_t seam_align_mm_per_segment = 4.0f;
//The following data structures hold all perimeter points for all PrintObject.
std::unordered_map<const PrintObject*, PrintObjectSeamData> m_seam_per_object;
@ -169,12 +168,11 @@ private:
std::vector<std::pair<size_t, size_t>> find_seam_string(const PrintObject *po,
std::pair<size_t, size_t> start_seam,
const SeamPlacerImpl::SeamComparator &comparator,
std::optional<std::pair<size_t, size_t>> &out_best_moved_seam,
size_t& out_moved_seams_count) const;
float& string_weight) const;
std::optional<std::pair<size_t, size_t>> find_next_seam_in_layer(
const std::vector<PrintObjectSeamData::LayerSeams> &layers,
const std::pair<size_t, size_t> &prev_point_index,
const size_t layer_idx, const float slice_z,
const Vec3f& projected_position,
const size_t layer_idx, const float max_distance,
const SeamPlacerImpl::SeamComparator &comparator) const;
};

4
src/libslic3r/Geometry/Curves.hpp
View File

@ -15,8 +15,8 @@ template<int Dimension, typename NumberType>
struct PolynomialCurve {
Eigen::MatrixXf coefficients;
Vec3f get_fitted_value(const NumberType value) const {
auto result = Vec<Dimension, NumberType>::Zero();
Vec<Dimension, NumberType> get_fitted_value(const NumberType& value) const {
Vec<Dimension, NumberType> result = Vec<Dimension, NumberType>::Zero();
size_t order = this->coefficients.rows() - 1;
auto x = NumberType(1.);
for (size_t index = 0; index < order + 1; ++index, x *= value)