PrusaSlicer-NonPlainar/lib/Slic3r/Print/Object.pm
2012-10-22 13:21:11 +02:00

644 lines
30 KiB
Perl

package Slic3r::Print::Object;
use Moo;
use Slic3r::ExtrusionPath ':roles';
use Slic3r::Geometry qw(scale unscale deg2rad scaled_epsilon);
use Slic3r::Geometry::Clipper qw(diff_ex intersection_ex union_ex);
use Slic3r::Surface ':types';
has 'print' => (is => 'ro', weak_ref => 1, required => 1);
has 'input_file' => (is => 'rw', required => 0);
has 'meshes' => (is => 'rw', default => sub { [] }); # by region_id
has 'size' => (is => 'rw', required => 1);
has 'copies' => (is => 'rw', default => sub {[ [0,0] ]});
has 'layers' => (is => 'rw', default => sub { [] });
sub layer_count {
my $self = shift;
return scalar @{ $self->layers };
}
sub layer {
my $self = shift;
my ($layer_id) = @_;
# extend our print by creating all necessary layers
for (my $i = $self->layer_count; $i <= $layer_id; $i++) {
push @{ $self->layers }, Slic3r::Layer->new(id => $i, object => $self);
}
return $self->layers->[$layer_id];
}
sub slice {
my $self = shift;
my %params = @_;
# process facets
for my $region_id (0 .. $#{$self->meshes}) {
my $mesh = $self->meshes->[$region_id]; # ignore undef meshes
my $apply_lines = sub {
my $lines = shift;
foreach my $layer_id (keys %$lines) {
my $layerm = $self->layer($layer_id)->region($region_id);
push @{$layerm->lines}, @{$lines->{$layer_id}};
}
};
Slic3r::parallelize(
disable => ($#{$mesh->facets} < 500), # don't parallelize when too few facets
items => [ 0..$#{$mesh->facets} ],
thread_cb => sub {
my $q = shift;
my $result_lines = {};
while (defined (my $facet_id = $q->dequeue)) {
my $lines = $mesh->slice_facet($self, $facet_id);
foreach my $layer_id (keys %$lines) {
$result_lines->{$layer_id} ||= [];
push @{ $result_lines->{$layer_id} }, @{ $lines->{$layer_id} };
}
}
return $result_lines;
},
collect_cb => sub {
$apply_lines->($_[0]);
},
no_threads_cb => sub {
for (0..$#{$mesh->facets}) {
my $lines = $mesh->slice_facet($self, $_);
$apply_lines->($lines);
}
},
);
}
die "Invalid input file\n" if !@{$self->layers};
# free memory
$self->meshes(undef) unless $params{keep_meshes};
# remove last layer if empty
# (we might have created it because of the $max_layer = ... + 1 code in TriangleMesh)
pop @{$self->layers} if !map @{$_->lines}, @{$self->layers->[-1]->regions};
foreach my $layer (@{ $self->layers }) {
# make sure all layers contain layer region objects for all regions
$layer->region($_) for 0 .. ($self->print->regions_count-1);
Slic3r::debugf "Making surfaces for layer %d (slice z = %f):\n",
$layer->id, unscale $layer->slice_z if $Slic3r::debug;
# layer currently has many lines representing intersections of
# model facets with the layer plane. there may also be lines
# that we need to ignore (for example, when two non-horizontal
# facets share a common edge on our plane, we get a single line;
# however that line has no meaning for our layer as it's enclosed
# inside a closed polyline)
# build surfaces from sparse lines
foreach my $layerm (@{$layer->regions}) {
my ($slicing_errors, $loops) = Slic3r::TriangleMesh::make_loops($layerm->lines);
$layer->slicing_errors(1) if $slicing_errors;
$layerm->make_surfaces($loops);
# free memory
$layerm->lines(undef);
}
# merge all regions' slices to get islands
$layer->make_slices;
}
# detect slicing errors
my $warning_thrown = 0;
for my $i (0 .. $#{$self->layers}) {
my $layer = $self->layers->[$i];
next unless $layer->slicing_errors;
if (!$warning_thrown) {
warn "The model has overlapping or self-intersecting facets. I tried to repair it, "
. "however you might want to check the results or repair the input file and retry.\n";
$warning_thrown = 1;
}
# try to repair the layer surfaces by merging all contours and all holes from
# neighbor layers
Slic3r::debugf "Attempting to repair layer %d\n", $i;
foreach my $region_id (0 .. $#{$layer->regions}) {
my $layerm = $layer->region($region_id);
my (@upper_surfaces, @lower_surfaces);
for (my $j = $i+1; $j <= $#{$self->layers}; $j++) {
if (!$self->layers->[$j]->slicing_errors) {
@upper_surfaces = @{$self->layers->[$j]->region($region_id)->slices};
last;
}
}
for (my $j = $i-1; $j >= 0; $j--) {
if (!$self->layers->[$j]->slicing_errors) {
@lower_surfaces = @{$self->layers->[$j]->region($region_id)->slices};
last;
}
}
my $union = union_ex([
map $_->expolygon->contour, @upper_surfaces, @lower_surfaces,
]);
my $diff = diff_ex(
[ map @$_, @$union ],
[ map $_->expolygon->holes, @upper_surfaces, @lower_surfaces, ],
);
@{$layerm->slices} = map Slic3r::Surface->new
(expolygon => $_, surface_type => S_TYPE_INTERNAL),
@$diff;
}
# update layer slices after repairing the single regions
$layer->make_slices;
}
# remove empty layers from bottom
while (@{$self->layers} && !@{$self->layers->[0]->slices} && !map @{$_->thin_walls}, @{$self->layers->[0]->regions}) {
shift @{$self->layers};
for (my $i = 0; $i <= $#{$self->layers}; $i++) {
$self->layers->[$i]->id($i);
}
}
warn "No layers were detected. You might want to repair your STL file and retry.\n"
if !@{$self->layers};
}
sub make_perimeters {
my $self = shift;
# compare each layer to the one below, and mark those slices needing
# one additional inner perimeter, like the top of domed objects-
# this algorithm makes sure that almost one perimeter is overlapping
if ($Slic3r::Config->extra_perimeters && $Slic3r::Config->perimeters > 0) {
for my $region_id (0 .. ($self->print->regions_count-1)) {
for my $layer_id (0 .. $self->layer_count-2) {
my $layerm = $self->layers->[$layer_id]->regions->[$region_id];
my $upper_layerm = $self->layers->[$layer_id+1]->regions->[$region_id];
my $perimeter_flow = $layerm->perimeter_flow;
my $overlap = $perimeter_flow->spacing; # one perimeter
# compute polygons representing the thickness of the first external perimeter of
# the upper layer slices
my $upper = diff_ex(
[ map @$_, map $_->expolygon->offset_ex(+ 0.5 * $perimeter_flow->scaled_spacing), @{$upper_layerm->slices} ],
[ map @$_, map $_->expolygon->offset_ex(- scale($overlap) + (0.5 * $perimeter_flow->scaled_spacing)), @{$upper_layerm->slices} ],
);
next if !@$upper;
# we need to limit our detection to the areas which would actually benefit from
# more perimeters. so, let's compute the area we want to ignore
my $ignore = [];
{
my $diff = diff_ex(
[ map @$_, map $_->expolygon->offset_ex(- ($Slic3r::Config->perimeters-0.5) * $perimeter_flow->scaled_spacing), @{$layerm->slices} ],
[ map @{$_->expolygon}, @{$upper_layerm->slices} ],
);
$ignore = [ map @$_, map $_->offset_ex($perimeter_flow->scaled_spacing), @$diff ];
}
foreach my $slice (@{$layerm->slices}) {
my $hypothetical_perimeter_num = $Slic3r::Config->perimeters + 1;
CYCLE: while (1) {
# compute polygons representing the thickness of the hypotetical new internal perimeter
# of our slice
my $hypothetical_perimeter;
{
my $outer = [ map @$_, $slice->expolygon->offset_ex(- ($hypothetical_perimeter_num-1.5) * $perimeter_flow->scaled_spacing - scaled_epsilon) ];
last CYCLE if !@$outer;
my $inner = [ map @$_, $slice->expolygon->offset_ex(- ($hypothetical_perimeter_num-0.5) * $perimeter_flow->scaled_spacing) ];
last CYCLE if !@$inner;
$hypothetical_perimeter = diff_ex($outer, $inner);
}
last CYCLE if !@$hypothetical_perimeter;
my $intersection = intersection_ex([ map @$_, @$upper ], [ map @$_, @$hypothetical_perimeter ]);
$intersection = diff_ex([ map @$_, @$intersection ], $ignore) if @$ignore;
last CYCLE if !@{ $intersection };
Slic3r::debugf " adding one more perimeter at layer %d\n", $layer_id;
$slice->additional_inner_perimeters(($slice->additional_inner_perimeters || 0) + 1);
$hypothetical_perimeter_num++;
}
}
}
}
}
$_->make_perimeters for @{$self->layers};
}
sub detect_surfaces_type {
my $self = shift;
Slic3r::debugf "Detecting solid surfaces...\n";
# prepare a reusable subroutine to make surface differences
my $surface_difference = sub {
my ($subject_surfaces, $clip_surfaces, $result_type, $layerm) = @_;
my $expolygons = diff_ex(
[ map { ref $_ eq 'ARRAY' ? $_ : ref $_ eq 'Slic3r::ExPolygon' ? @$_ : $_->p } @$subject_surfaces ],
[ map { ref $_ eq 'ARRAY' ? $_ : ref $_ eq 'Slic3r::ExPolygon' ? @$_ : $_->p } @$clip_surfaces ],
1,
);
return grep $_->contour->is_printable($layerm->flow->width),
map Slic3r::Surface->new(expolygon => $_, surface_type => $result_type),
@$expolygons;
};
for my $region_id (0 .. ($self->print->regions_count-1)) {
for (my $i = 0; $i < $self->layer_count; $i++) {
my $layerm = $self->layers->[$i]->regions->[$region_id];
# comparison happens against the *full* slices (considering all regions)
my $upper_layer = $self->layers->[$i+1];
my $lower_layer = $i > 0 ? $self->layers->[$i-1] : undef;
my (@bottom, @top, @internal) = ();
# find top surfaces (difference between current surfaces
# of current layer and upper one)
if ($upper_layer) {
@top = $surface_difference->($layerm->slices, $upper_layer->slices, S_TYPE_TOP, $layerm);
} else {
# if no upper layer, all surfaces of this one are solid
@top = @{$layerm->slices};
$_->surface_type(S_TYPE_TOP) for @top;
}
# find bottom surfaces (difference between current surfaces
# of current layer and lower one)
if ($lower_layer) {
@bottom = $surface_difference->($layerm->slices, $lower_layer->slices, S_TYPE_BOTTOM, $layerm);
} else {
# if no lower layer, all surfaces of this one are solid
@bottom = @{$layerm->slices};
$_->surface_type(S_TYPE_BOTTOM) for @bottom;
}
# now, if the object contained a thin membrane, we could have overlapping bottom
# and top surfaces; let's do an intersection to discover them and consider them
# as bottom surfaces (to allow for bridge detection)
if (@top && @bottom) {
my $overlapping = intersection_ex([ map $_->p, @top ], [ map $_->p, @bottom ]);
Slic3r::debugf " layer %d contains %d membrane(s)\n", $layerm->id, scalar(@$overlapping);
@top = $surface_difference->([@top], $overlapping, S_TYPE_TOP, $layerm);
}
# find internal surfaces (difference between top/bottom surfaces and others)
@internal = $surface_difference->($layerm->slices, [@top, @bottom], S_TYPE_INTERNAL, $layerm);
# save surfaces to layer
@{$layerm->slices} = (@bottom, @top, @internal);
Slic3r::debugf " layer %d has %d bottom, %d top and %d internal surfaces\n",
$layerm->id, scalar(@bottom), scalar(@top), scalar(@internal);
}
# clip surfaces to the fill boundaries
foreach my $layer (@{$self->layers}) {
my $layerm = $layer->regions->[$region_id];
my $fill_boundaries = [ map @$_, @{$layerm->surfaces} ];
@{$layerm->surfaces} = ();
foreach my $surface (@{$layerm->slices}) {
my $intersection = intersection_ex(
[ $surface->p ],
$fill_boundaries,
);
push @{$layerm->surfaces}, map Slic3r::Surface->new
(expolygon => $_, surface_type => $surface->surface_type),
@$intersection;
}
}
}
}
sub discover_horizontal_shells {
my $self = shift;
Slic3r::debugf "==> DISCOVERING HORIZONTAL SHELLS\n";
my $area_threshold = $Slic3r::flow->scaled_spacing ** 2;
for my $region_id (0 .. ($self->print->regions_count-1)) {
for (my $i = 0; $i < $self->layer_count; $i++) {
my $layerm = $self->layers->[$i]->regions->[$region_id];
if ($Slic3r::Config->solid_infill_every_layers && ($i % $Slic3r::Config->solid_infill_every_layers) == 0) {
$_->surface_type(S_TYPE_INTERNALSOLID)
for grep $_->surface_type == S_TYPE_INTERNAL, @{$layerm->fill_surfaces};
}
foreach my $type (S_TYPE_TOP, S_TYPE_BOTTOM) {
# find surfaces of current type for current layer
# and offset them to take perimeters into account
my @surfaces = map $_->offset($Slic3r::Config->perimeters * $layerm->perimeter_flow->scaled_width),
grep $_->surface_type == $type, @{$layerm->fill_surfaces} or next;
my $surfaces_p = [ map $_->p, @surfaces ];
Slic3r::debugf "Layer %d has %d surfaces of type '%s'\n",
$i, scalar(@surfaces), ($type == S_TYPE_TOP ? 'top' : 'bottom');
for (my $n = $type == S_TYPE_TOP ? $i-1 : $i+1;
abs($n - $i) <= $Slic3r::Config->solid_layers-1;
$type == S_TYPE_TOP ? $n-- : $n++) {
next if $n < 0 || $n >= $self->layer_count;
Slic3r::debugf " looking for neighbors on layer %d...\n", $n;
my @neighbor_surfaces = @{$self->layers->[$n]->regions->[$region_id]->surfaces};
my @neighbor_fill_surfaces = @{$self->layers->[$n]->regions->[$region_id]->fill_surfaces};
# find intersection between neighbor and current layer's surfaces
# intersections have contours and holes
my $new_internal_solid = intersection_ex(
$surfaces_p,
[ map $_->p, grep { $_->surface_type == S_TYPE_INTERNAL || $_->surface_type == S_TYPE_INTERNALSOLID } @neighbor_surfaces ],
undef, 1,
);
next if !@$new_internal_solid;
# internal-solid are the union of the existing internal-solid surfaces
# and new ones
my $internal_solid = union_ex([
( map $_->p, grep $_->surface_type == S_TYPE_INTERNALSOLID, @neighbor_fill_surfaces ),
( map @$_, @$new_internal_solid ),
]);
# subtract intersections from layer surfaces to get resulting inner surfaces
my $internal = diff_ex(
[ map $_->p, grep $_->surface_type == S_TYPE_INTERNAL, @neighbor_fill_surfaces ],
[ map @$_, @$internal_solid ],
1,
);
Slic3r::debugf " %d internal-solid and %d internal surfaces found\n",
scalar(@$internal_solid), scalar(@$internal);
# Note: due to floating point math we're going to get some very small
# polygons as $internal; they will be removed by removed_small_features()
# assign resulting inner surfaces to layer
my $neighbor_fill_surfaces = $self->layers->[$n]->regions->[$region_id]->fill_surfaces;
@$neighbor_fill_surfaces = ();
push @$neighbor_fill_surfaces, Slic3r::Surface->new
(expolygon => $_, surface_type => S_TYPE_INTERNAL)
for @$internal;
# assign new internal-solid surfaces to layer
push @$neighbor_fill_surfaces, Slic3r::Surface->new
(expolygon => $_, surface_type => S_TYPE_INTERNALSOLID)
for @$internal_solid;
# assign top and bottom surfaces to layer
foreach my $s (Slic3r::Surface->group(grep { $_->surface_type == S_TYPE_TOP || $_->surface_type == S_TYPE_BOTTOM } @neighbor_fill_surfaces)) {
my $solid_surfaces = diff_ex(
[ map $_->p, @$s ],
[ map @$_, @$internal_solid, @$internal ],
1,
);
push @$neighbor_fill_surfaces, Slic3r::Surface->new
(expolygon => $_, surface_type => $s->[0]->surface_type, bridge_angle => $s->[0]->bridge_angle)
for @$solid_surfaces;
}
}
}
@{$layerm->fill_surfaces} = grep $_->expolygon->area > $area_threshold, @{$layerm->fill_surfaces};
}
}
}
# combine fill surfaces across layers
sub combine_infill {
my $self = shift;
return unless $Slic3r::Config->infill_every_layers > 1 && $Slic3r::Config->fill_density > 0;
my $area_threshold = $Slic3r::flow->scaled_spacing ** 2;
for my $region_id (0 .. ($self->print->regions_count-1)) {
# start from bottom, skip first layer
for (my $i = 1; $i < $self->layer_count; $i++) {
my $layerm = $self->layers->[$i]->regions->[$region_id];
# skip layer if no internal fill surfaces
next if !grep $_->surface_type == S_TYPE_INTERNAL, @{$layerm->fill_surfaces};
# for each possible depth, look for intersections with the lower layer
# we do this from the greater depth to the smaller
for (my $d = $Slic3r::Config->infill_every_layers - 1; $d >= 1; $d--) {
next if ($i - $d) < 0;
my $lower_layerm = $self->layer($i - 1)->regions->[$region_id];
# select surfaces of the lower layer having the depth we're looking for
my @lower_surfaces = grep $_->depth_layers == $d && $_->surface_type == S_TYPE_INTERNAL,
@{$lower_layerm->fill_surfaces};
next if !@lower_surfaces;
# calculate intersection between our surfaces and theirs
my $intersection = intersection_ex(
[ map $_->p, grep $_->depth_layers <= $d, @lower_surfaces ],
[ map $_->p, grep $_->surface_type == S_TYPE_INTERNAL, @{$layerm->fill_surfaces} ],
undef, 1,
);
# purge intersections, skip tiny regions
@$intersection = grep $_->area > $area_threshold, @$intersection;
next if !@$intersection;
# new fill surfaces of the current layer are:
# - any non-internal surface
# - intersections found (with a $d + 1 depth)
# - any internal surface not belonging to the intersection (with its original depth)
{
my @new_surfaces = ();
push @new_surfaces, grep $_->surface_type != S_TYPE_INTERNAL, @{$layerm->fill_surfaces};
push @new_surfaces, map Slic3r::Surface->new
(expolygon => $_, surface_type => S_TYPE_INTERNAL, depth_layers => $d + 1), @$intersection;
foreach my $depth (reverse $d..$Slic3r::Config->infill_every_layers) {
push @new_surfaces, map Slic3r::Surface->new
(expolygon => $_, surface_type => S_TYPE_INTERNAL, depth_layers => $depth),
# difference between our internal layers with depth == $depth
# and the intersection found
@{diff_ex(
[
map $_->p, grep $_->surface_type == S_TYPE_INTERNAL && $_->depth_layers == $depth,
@{$layerm->fill_surfaces},
],
[ map @$_, @$intersection ],
1,
)};
}
@{$layerm->fill_surfaces} = @new_surfaces;
}
# now we remove the intersections from lower layer
{
my @new_surfaces = ();
push @new_surfaces, grep $_->surface_type != S_TYPE_INTERNAL, @{$lower_layerm->fill_surfaces};
foreach my $depth (1..$Slic3r::Config->infill_every_layers) {
push @new_surfaces, map Slic3r::Surface->new
(expolygon => $_, surface_type => S_TYPE_INTERNAL, depth_layers => $depth),
# difference between internal layers with depth == $depth
# and the intersection found
@{diff_ex(
[
map $_->p, grep $_->surface_type == S_TYPE_INTERNAL && $_->depth_layers == $depth,
@{$lower_layerm->fill_surfaces},
],
[ map @$_, @$intersection ],
1,
)};
}
@{$lower_layerm->fill_surfaces} = @new_surfaces;
}
}
}
}
}
sub generate_support_material {
my $self = shift;
my $flow = $self->print->support_material_flow;
my $threshold_rad = deg2rad($Slic3r::Config->support_material_threshold + 1); # +1 makes the threshold inclusive
my $overhang_width = $threshold_rad == 0 ? undef : scale $Slic3r::Config->layer_height * ((cos $threshold_rad) / (sin $threshold_rad));
my $distance_from_object = 1.5 * $flow->scaled_width;
# determine support regions in each layer (for upper layers)
Slic3r::debugf "Detecting regions\n";
my %layers = ();
{
my @current_support_regions = (); # expolygons we've started to support (i.e. below the empty interface layers)
my @queue = (); # the number of items of this array determines the number of empty interface layers
for my $i (reverse 0 .. $#{$self->layers}) {
my $layer = $self->layers->[$i];
my $lower_layer = $i > 0 ? $self->layers->[$i-1] : undef;
# step 1: generate support material in current layer (for upper layers)
push @current_support_regions, @{ shift @queue } if @queue && $i < $#{$self->layers};
@current_support_regions = @{diff_ex(
[ map @$_, @current_support_regions ],
[ map @$_, @{$layer->slices} ],
)};
$layers{$i} = diff_ex(
[ map @$_, @current_support_regions ],
[ map @$_, map $_->offset_ex($distance_from_object), @{$layer->slices} ],
);
$_->simplify($flow->scaled_spacing * 2) for @{$layers{$i}};
# step 2: get layer overhangs and put them into queue for adding support inside lower layers
# we need an angle threshold for this
my @overhangs = ();
if ($lower_layer) {
@overhangs = map $_->offset_ex(2 * $overhang_width), @{diff_ex(
[ map @$_, map $_->offset_ex(-$overhang_width), @{$layer->slices} ],
[ map @$_, @{$lower_layer->slices} ],
1,
)};
}
push @queue, [@overhangs];
}
}
return if !map @$_, values %layers;
# generate paths for the pattern that we're going to use
Slic3r::debugf "Generating patterns\n";
my $support_patterns = []; # in case we want cross-hatching
{
# 0.5 makes sure the paths don't get clipped externally when applying them to layers
my @support_material_areas = map $_->offset_ex(- 0.5 * $flow->scaled_width),
@{union_ex([ map $_->contour, map @$_, values %layers ])};
my $fill = Slic3r::Fill->new(print => $self->print);
my $filler = $fill->filler($Slic3r::Config->support_material_pattern);
$filler->angle($Slic3r::Config->support_material_angle);
{
my @patterns = ();
foreach my $expolygon (@support_material_areas) {
my @paths = $filler->fill_surface(
Slic3r::Surface->new(expolygon => $expolygon),
density => $flow->spacing / $Slic3r::Config->support_material_spacing,
flow_spacing => $flow->spacing,
);
my $params = shift @paths;
push @patterns,
map Slic3r::ExtrusionPath->new(
polyline => Slic3r::Polyline->new(@$_),
role => EXTR_ROLE_SUPPORTMATERIAL,
depth_layers => 1,
flow_spacing => $params->{flow_spacing},
), @paths;
}
push @$support_patterns, [@patterns];
}
if (0) {
require "Slic3r/SVG.pm";
Slic3r::SVG::output(undef, "support_$_.svg",
polylines => [ map $_->polyline, map @$_, $support_patterns->[$_] ],
polygons => [ map @$_, @support_material_areas ],
) for 0 .. $#$support_patterns;
}
}
# apply the pattern to layers
Slic3r::debugf "Applying patterns\n";
{
my $clip_pattern = sub {
my ($layer_id, $expolygons) = @_;
my @paths = ();
foreach my $expolygon (@$expolygons) {
push @paths,
map $_->pack,
map {
$_->flow_spacing($self->print->first_layer_support_material_flow->spacing)
if $layer_id == 0;
$_;
}
map $_->clip_with_expolygon($expolygon),
map $_->clip_with_polygon($expolygon->bounding_box_polygon),
@{$support_patterns->[ $layer_id % @$support_patterns ]};
};
return @paths;
};
my %layer_paths = ();
Slic3r::parallelize(
items => [ keys %layers ],
thread_cb => sub {
my $q = shift;
my $paths = {};
while (defined (my $layer_id = $q->dequeue)) {
$paths->{$layer_id} = [ $clip_pattern->($layer_id, $layers{$layer_id}) ];
}
return $paths;
},
collect_cb => sub {
my $paths = shift;
$layer_paths{$_} = $paths->{$_} for keys %$paths;
},
no_threads_cb => sub {
$layer_paths{$_} = [ $clip_pattern->($_, $layers{$_}) ] for keys %layers;
},
);
foreach my $layer_id (keys %layer_paths) {
my $layer = $self->layers->[$layer_id];
$layer->support_fills(Slic3r::ExtrusionPath::Collection->new);
push @{$layer->support_fills->paths}, @{$layer_paths{$layer_id}};
}
}
}
1;