From 887634e1e2174b1bee55f4a3d37056ab57c2f4b7 Mon Sep 17 00:00:00 2001
From: Alessandro Ranellucci <aar@cpan.org>
Date: Mon, 29 Oct 2012 19:54:04 +0100
Subject: [PATCH] Use G92 to apply Z offset. #486

---
 lib/Slic3r/GCode.pm | 2 +-
 lib/Slic3r/Print.pm | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/lib/Slic3r/GCode.pm b/lib/Slic3r/GCode.pm
index 658fca26a..a127c9bfb 100644
--- a/lib/Slic3r/GCode.pm
+++ b/lib/Slic3r/GCode.pm
@@ -71,7 +71,7 @@ sub move_z {
     my $self = shift;
     my ($z, $comment) = @_;
     
-    $z = $Slic3r::Config->z_offset + $z * &Slic3r::SCALING_FACTOR;
+    $z = $z * &Slic3r::SCALING_FACTOR;
     
     my $gcode = "";
     $gcode .= $self->retract(move_z => $z);
diff --git a/lib/Slic3r/Print.pm b/lib/Slic3r/Print.pm
index 05eef7479..e6a1990e7 100644
--- a/lib/Slic3r/Print.pm
+++ b/lib/Slic3r/Print.pm
@@ -705,6 +705,14 @@ sub write_gcode {
         }
     }
     
+    # apply Z offset
+    if ($Slic3r::Config->z_offset > 0) {
+        printf $fh "G1 Z%s ; set Z offset\n", $Slic3r::Config->z_offset;
+        print  $fh "G92 Z0 ; set Z offset\n";
+    } elsif ($Slic3r::Config->z_offset < 0) {
+        printf $fh "G92 Z%s ; set Z offset\n", 1*(-$Slic3r::Config->z_offset);
+    }
+    
     # calculate X,Y shift to center print around specified origin
     my @print_bb = $self->bounding_box;
     my @shift = (