diff --git a/lib/Slic3r/Print.pm b/lib/Slic3r/Print.pm
index 91a4dca6a..894676867 100644
--- a/lib/Slic3r/Print.pm
+++ b/lib/Slic3r/Print.pm
@@ -538,7 +538,7 @@ sub write_gcode {
         
         # print objects from the smallest to the tallest to avoid collisions
         # when moving onto next object starting point
-        my @obj_idx = sort { $a->layer_count <=> $b->layer_count } 0..$#{$self->objects};
+        my @obj_idx = sort { $self->objects->[$a]->layer_count <=> $self->objects->[$b]->layer_count } 0..$#{$self->objects};
         
         my $finished_objects = 0;
         for my $obj_idx (@obj_idx) {