#!/usr/bin/perl # # slicer.pl - Standalone STL to Gnuplot slicer # # Written 2015 by Werner Almesberger # Copyright 2015 by Werner Almesberger # # This program//library is free software; you can redistribute it and/or # modify it under the terms of the GNU Lesser General Public # License as published by the Free Software Foundation; either # version 2.1 of the License, or (at your option) any later version. # $epsilon = 0.0001; # cutting offset $height = 10; # height of workpiece $margin = 5; # margin of workpiece box $end = 0; # offset to add at the last layer $flip = 1; # flip piece $z0 = -35; # reference tool position $z_step = 1; #----- Read the STL mesh ------------------------------------------------------ $xmin = $xmax = $ymin = $ymax = $zmin = $zmax = undef; $v_n = 0; $e_n = 0; while (<>) { if (/\bfacet/) { undef @f; next; } if (/endfacet/) { if ($f[2] == $f[5] && $f[2] == $f[8]) { $z_level{$f[2]} = 1; } else { push(@m, [ @f ]); } next; } if (/vertex\s+/) { my @tmp = split(/\s+/, $'); ($tmp[0], $tmp[2]) = (-$tmp[0], -$tmp[2]) if $flip; $xmin = $tmp[0] unless defined $xmin && $xmin < $tmp[0]; $xmax = $tmp[0] unless defined $xmax && $xmax > $tmp[0]; $ymin = $tmp[1] unless defined $ymin && $ymin < $tmp[1]; $ymax = $tmp[1] unless defined $ymax && $ymax > $tmp[1]; $zmin = $tmp[2] unless defined $zmin && $zmin < $tmp[2]; $zmax = $tmp[2] unless defined $zmax && $zmax > $tmp[2]; push(@f, @tmp); next; } } print STDERR "bbox\t($xmin, $ymin, $zmin)\n\t($xmax, $ymax, $zmax)\n"; #----- Calculate Z offset ----------------------------------------------------- # align with bottom (zmin == 0), z_pos = height - zoff $z_off = $z0 - $zmin - $height; $z_pos = $height + $zmin; #----- Perform the slicing ---------------------------------------------------- sub cut { local ($z, $a, $b, @f) = @_; if ($f[$a + 2] < $z && $f[$b + 2] > $z) { my $dx = $f[$b] - $f[$a]; my $dy = $f[$b + 1] - $f[$a + 1]; my $dz = $f[$b + 2] - $f[$a + 2]; my $f = ($z - $f[$a + 2]) / $dz; return [ $dx * $f + $f[$a], $dy * $f + $f[$a + 1] ]; } if ($f[$a + 2] > $z && $f[$b + 2] < $z) { return &cut($z, $b, $a, @f); } return (); } sub remove { local ($a, $b) = @_; #print STDERR "\tremove $b from $a (", join(",", @{ $next{$a} }), "\n"; my @tmp = grep($_ ne $b, @{ $next{$a} }); if ($#tmp == -1) { delete $next{$a}; } else { $next{$a} = [ @tmp ]; } } @z_levels = sort { $b <=> $a } keys %z_level; for $level (@z_levels) { my $z_cut = $level + $epsilon; print STDERR "level $level (cut at $z_cut)\n"; undef %path; for (@m) { my @f = @{ $_ }; my @p = &cut($z_cut, 0, 3, @f); push(@p, &cut($z_cut, 0, 6, @f)); push(@p, &cut($z_cut, 3, 6, @f)); next if $#p < 1; die "BAD $#p" if $#p > 1; my $a = "$p[0][0] $p[0][1]"; my $b = "$p[1][0] $p[1][1]"; push(@{ $path{$a} }, $b); push(@{ $path{$b} }, $a); # print STDERR "$z: ($a) to ($b)\n"; } while (1) { if (defined $z_step) { $z_pos = $z_pos - $z_step > $level ? $z_pos - $z_step : $level; } else { $z_pos = $level; } my $z = $z_pos + $z_off; $z += $end if $z_pos == $z_levels[$#z_levels]; print STDERR "\t$z_pos @ $z\n"; if (defined $margin) { print $xmin - $margin, " ", $ymin - $margin, " $z\n"; print $xmax + $margin, " ", $ymin - $margin, " $z\n"; print $xmax + $margin, " ", $ymax + $margin, " $z\n"; print $xmin - $margin, " ", $ymax + $margin, " $z\n"; print $xmin - $margin, " ", $ymin - $margin, " $z\n\n"; } %next = %path; while (1) { my @k = keys %next; last if $#k == -1; my $p0 = $k[0]; $p = $p0; while (1) { my $next = $next{$p}[0]; print "$p $z\n"; # print STDERR "at $p\n"; # print STDERR "\tnext $next\n"; die "open path" unless defined $next; &remove($p, $next); &remove($next, $p); last if $p0 eq $next; $p = $next; } print "$p0 $z\n"; print "\n"; } last if $z_pos == $level; } }