diff --git a/lib/Slic3r/ExtrusionPath.pm b/lib/Slic3r/ExtrusionPath.pm
index 56e2c349e..7aaf88b5c 100644
--- a/lib/Slic3r/ExtrusionPath.pm
+++ b/lib/Slic3r/ExtrusionPath.pm
@@ -148,6 +148,7 @@ sub detect_arcs {
     my $self = shift;
     my ($max_angle, $len_epsilon) = @_;
     
+    $self->deserialize;
     $max_angle = deg2rad($max_angle || 15);
     $len_epsilon ||= 10 / $Slic3r::scaling_factor;
     
diff --git a/t/arcs.t b/t/arcs.t
index b63c2660e..44535e946 100644
--- a/t/arcs.t
+++ b/t/arcs.t
@@ -11,7 +11,7 @@ BEGIN {
 
 use Slic3r;
 use Slic3r::ExtrusionPath ':roles';
-use Slic3r::Geometry qw(epsilon);
+use Slic3r::Geometry qw(epsilon scale X Y);
 
 {
     my $path = Slic3r::ExtrusionPath->new(polyline => Slic3r::Polyline->new(
@@ -32,23 +32,27 @@ use Slic3r::Geometry qw(epsilon);
 #==========================================================
 
 {
-    my $path1 = Slic3r::ExtrusionPath->new(polyline => Slic3r::Polyline->new(
+    my @points = map [ scale $_->[0], scale $_->[1] ], (
         [10,20], [10.7845909572784,19.9691733373313], [11.5643446504023,19.8768834059514], 
         [12.3344536385591,19.7236992039768], [13.0901699437495,19.5105651629515], 
         [13.8268343236509,19.2387953251129], [14.5399049973955,18.9100652418837], 
         [15.2249856471595,18.5264016435409], [15.8778525229247,18.0901699437495], 
-        [16.4944804833018,17.6040596560003],
-    ), role => EXTR_ROLE_FILL);
+        [16.4944804833018,17.6040596560003]
+    );
+    my $path1 = Slic3r::ExtrusionPath->new(
+        polyline    => Slic3r::Polyline->new(@points),
+        role        => EXTR_ROLE_FILL,
+    );
     my $path2 = Slic3r::ExtrusionPath->new(
-        polyline    => Slic3r::Polyline->new(reverse @{$path1->points}),
+        polyline    => Slic3r::Polyline->new(reverse @points),
         role        => EXTR_ROLE_FILL,
     );
     
     my $collection1 = Slic3r::ExtrusionPath::Collection->new(paths => [$path1]);
     my $collection2 = Slic3r::ExtrusionPath::Collection->new(paths => [$path2]);
     
-    $collection1->detect_arcs(10, 1);
-    $collection2->detect_arcs(10, 1);
+    $collection1->detect_arcs(10, scale 1);
+    $collection2->detect_arcs(10, scale 1);
     
     is scalar(@{$collection1->paths}), 1, 'path collection now contains one path';
     is scalar(@{$collection2->paths}), 1, 'path collection now contains one path';
@@ -56,18 +60,19 @@ use Slic3r::Geometry qw(epsilon);
     isa_ok $collection1->paths->[0], 'Slic3r::ExtrusionPath::Arc', 'path';
     isa_ok $collection2->paths->[0], 'Slic3r::ExtrusionPath::Arc', 'path';
 
-    my $expected_length = 7.06858347057701;
-    ok abs($collection1->paths->[0]->length - $expected_length) < epsilon, 'cw oriented arc has correct length';
-    ok abs($collection2->paths->[0]->length - $expected_length) < epsilon, 'ccw oriented arc has correct length';
+    $_->deserialize for $collection1->paths->[0], $collection2->paths->[0];
+    my $expected_length = scale 7.06858347057701;
+    ok abs($collection1->paths->[0]->length - $expected_length) < scale epsilon, 'cw oriented arc has correct length';
+    ok abs($collection2->paths->[0]->length - $expected_length) < scale epsilon, 'ccw oriented arc has correct length';
 
     is $collection1->paths->[0]->orientation, 'cw', 'cw orientation was correctly detected';
     is $collection2->paths->[0]->orientation, 'ccw', 'ccw orientation was correctly detected';
     
     my $center1 = [ map sprintf('%.0f', $_), @{ $collection1->paths->[0]->center } ];
-    is_deeply $center1, [10,10], 'center was correctly detected';
+    ok abs($center1->[X] - scale 10) < scale epsilon && abs($center1->[Y] - scale 10) < scale epsilon, 'center was correctly detected';
     
     my $center2 = [ map sprintf('%.0f', $_), @{ $collection2->paths->[0]->center } ];
-    is_deeply $center2, [10,10], 'center was correctly detected';
+    ok abs($center2->[X] - scale 10) < scale epsilon && abs($center1->[Y] - scale 10) < scale epsilon, 'center was correctly detected';
 }
 
 #==========================================================