diff --git a/lib/Slic3r/Surface.pm b/lib/Slic3r/Surface.pm
index e0b6394f1..e1b84ad5a 100644
--- a/lib/Slic3r/Surface.pm
+++ b/lib/Slic3r/Surface.pm
@@ -7,12 +7,6 @@ our @ISA = qw(Exporter);
 our @EXPORT_OK   = qw(S_TYPE_TOP S_TYPE_BOTTOM S_TYPE_INTERNAL S_TYPE_INTERNALSOLID S_TYPE_INTERNALBRIDGE S_TYPE_INTERNALVOID);
 our %EXPORT_TAGS = (types => \@EXPORT_OK);
 
-# delegate handles
-sub contains_point  { $_[0]->expolygon->contains_point }
-sub lines           { $_[0]->expolygon->lines }
-sub contour         { $_[0]->expolygon->contour }
-sub holes           { $_[0]->expolygon->holes }
-
 # static method to group surfaces having same surface_type, bridge_angle and thickness*
 sub group {
     my $class = shift;
@@ -43,20 +37,4 @@ sub p {
     return @{$self->polygons};
 }
 
-sub is_solid {
-    my $self = shift;
-    my $type = $self->surface_type;
-    # S_TYPE_INTERNALBRIDGE is not solid because we can't merge it with other solid types
-    return $type == S_TYPE_TOP
-        || $type == S_TYPE_BOTTOM
-        || $type == S_TYPE_INTERNALSOLID;
-}
-
-sub is_bridge {
-    my $self = shift;
-    my $type = $self->surface_type;
-    return $type == S_TYPE_BOTTOM
-        || $type == S_TYPE_INTERNALBRIDGE;
-}
-
 1;
diff --git a/xs/src/Surface.cpp b/xs/src/Surface.cpp
index 636467210..fadb47213 100644
--- a/xs/src/Surface.cpp
+++ b/xs/src/Surface.cpp
@@ -8,6 +8,21 @@ Surface::area() const
     return this->expolygon.area();
 }
 
+bool
+Surface::is_solid() const
+{
+    return this->surface_type == stTop
+        || this->surface_type == stBottom
+        || this->surface_type == stInternalSolid;
+}
+
+bool
+Surface::is_bridge() const
+{
+    return this->surface_type == stBottom
+        || this->surface_type == stInternalBridge;
+}
+
 #ifdef SLIC3RXS
 SV*
 Surface::to_SV_ref() {
diff --git a/xs/src/Surface.hpp b/xs/src/Surface.hpp
index f7c72f7fc..5c4d65ef2 100644
--- a/xs/src/Surface.hpp
+++ b/xs/src/Surface.hpp
@@ -17,6 +17,8 @@ class Surface
     double          bridge_angle;
     unsigned short  extra_perimeters;
     double area() const;
+    bool is_solid() const;
+    bool is_bridge() const;
     
     #ifdef SLIC3RXS
     SV* to_SV_ref();
diff --git a/xs/src/SurfaceCollection.cpp b/xs/src/SurfaceCollection.cpp
index b65c80622..898db92e1 100644
--- a/xs/src/SurfaceCollection.cpp
+++ b/xs/src/SurfaceCollection.cpp
@@ -1,4 +1,5 @@
 #include "SurfaceCollection.hpp"
+#include <map>
 
 namespace Slic3r {
 
@@ -18,4 +19,36 @@ SurfaceCollection::simplify(double tolerance)
     this->surfaces = ss;
 }
 
+/* group surfaces by common properties */
+void
+SurfaceCollection::group(std::vector<Surfaces> &retval, bool merge_solid) const
+{
+    typedef std::map<t_surface_group_key,Surfaces> t_unique_map;
+    t_unique_map unique_map;
+    
+    for (Surfaces::const_iterator it = this->surfaces.begin(); it != this->surfaces.end(); ++it) {
+        // build the t_surface_group_key struct with this surface's properties
+        t_surface_group_key key;
+        if (merge_solid && it->is_solid()) {
+            key.surface_type = stTop;
+        } else {
+            key.surface_type = it->surface_type;
+        }
+        key.thickness           = it->thickness;
+        key.thickness_layers    = it->thickness_layers;
+        key.bridge_angle        = it->bridge_angle;
+        
+        // check whether we already have a group for these properties
+        if (unique_map.find(key) == unique_map.end()) {
+            // no group exists, add it
+            unique_map[key] = Surfaces();
+        }
+        unique_map[key].push_back(*it);
+    }
+    
+    retval.reserve(unique_map.size());
+    for (t_unique_map::const_iterator it = unique_map.begin(); it != unique_map.end(); ++it)
+        retval.push_back(it->second);
+}
+
 }
diff --git a/xs/src/SurfaceCollection.hpp b/xs/src/SurfaceCollection.hpp
index c28894560..e941cee21 100644
--- a/xs/src/SurfaceCollection.hpp
+++ b/xs/src/SurfaceCollection.hpp
@@ -2,14 +2,30 @@
 #define slic3r_SurfaceCollection_hpp_
 
 #include "Surface.hpp"
+#include <vector>
 
 namespace Slic3r {
 
+struct t_surface_group_key {
+    SurfaceType     surface_type;
+    double          thickness;
+    unsigned short  thickness_layers;
+    double          bridge_angle;
+    
+    bool operator< (const t_surface_group_key &key) const {
+        return (this->surface_type      < key.surface_type)
+            || (this->thickness         < key.thickness)
+            || (this->thickness_layers  < key.thickness_layers)
+            || (this->bridge_angle      < key.bridge_angle);
+    }
+};
+
 class SurfaceCollection
 {
     public:
     Surfaces surfaces;
     void simplify(double tolerance);
+    void group(std::vector<Surfaces> &retval, bool merge_solid = false) const;
 };
 
 }
diff --git a/xs/xsp/Surface.xsp b/xs/xsp/Surface.xsp
index 787db562f..868cc9833 100644
--- a/xs/xsp/Surface.xsp
+++ b/xs/xsp/Surface.xsp
@@ -14,6 +14,8 @@
     unsigned short thickness_layers()
         %code{% RETVAL = THIS->thickness_layers; %};
     double area();
+    bool is_solid() const;
+    bool is_bridge() const;
 %{
 
 Surface*