diff --git a/xs/src/libslic3r/ExPolygon.cpp b/xs/src/libslic3r/ExPolygon.cpp
index 06ba28ed2..e97c82532 100644
--- a/xs/src/libslic3r/ExPolygon.cpp
+++ b/xs/src/libslic3r/ExPolygon.cpp
@@ -198,7 +198,7 @@ ExPolygon::simplify_p(double tolerance) const
         p.points.pop_back();
         pp.push_back(p);
     }
-    simplify_polygons(pp, &pp);
+    pp = simplify_polygons(pp);
     return pp;
 }
 
diff --git a/xs/src/libslic3r/Fill/Fill.cpp b/xs/src/libslic3r/Fill/Fill.cpp
index b4c14bb6c..3a456c55d 100644
--- a/xs/src/libslic3r/Fill/Fill.cpp
+++ b/xs/src/libslic3r/Fill/Fill.cpp
@@ -168,11 +168,7 @@ void make_fill(LayerRegion &layerm, ExtrusionEntityCollection &out)
             continue;
         
         // get filler object
-#if SLIC3R_CPPVER >= 11
         std::unique_ptr<Fill> f = std::unique_ptr<Fill>(Fill::new_from_type(fill_pattern));
-#else
-        std::auto_ptr<Fill> f = std::auto_ptr<Fill>(Fill::new_from_type(fill_pattern));
-#endif
         f->set_bounding_box(layerm.layer()->object()->bounding_box());
         
         // calculate the actual flow we'll be using for this infill
diff --git a/xs/src/libslic3r/Geometry.cpp b/xs/src/libslic3r/Geometry.cpp
index e6354a869..314990734 100644
--- a/xs/src/libslic3r/Geometry.cpp
+++ b/xs/src/libslic3r/Geometry.cpp
@@ -317,12 +317,6 @@ rad2deg_dir(double angle)
     return rad2deg(angle);
 }
 
-double
-deg2rad(double angle)
-{
-    return PI * angle / 180.0;
-}
-
 void
 simplify_polygons(const Polygons &polygons, double tolerance, Polygons* retval)
 {
@@ -334,7 +328,7 @@ simplify_polygons(const Polygons &polygons, double tolerance, Polygons* retval)
         p.points.pop_back();
         pp.push_back(p);
     }
-    Slic3r::simplify_polygons(pp, retval);
+    *retval = Slic3r::simplify_polygons(pp);
 }
 
 double
diff --git a/xs/src/libslic3r/Geometry.hpp b/xs/src/libslic3r/Geometry.hpp
index a6d1bbb66..08ebe93ee 100644
--- a/xs/src/libslic3r/Geometry.hpp
+++ b/xs/src/libslic3r/Geometry.hpp
@@ -64,7 +64,7 @@ bool directions_parallel(double angle1, double angle2, double max_diff = 0);
 template<class T> bool contains(const std::vector<T> &vector, const Point &point);
 double rad2deg(double angle);
 double rad2deg_dir(double angle);
-double deg2rad(double angle);
+template<typename T> T deg2rad(T angle) { return T(PI) * angle / T(180.0); }
 void simplify_polygons(const Polygons &polygons, double tolerance, Polygons* retval);
 
 double linint(double value, double oldmin, double oldmax, double newmin, double newmax);
diff --git a/xs/src/libslic3r/Layer.cpp b/xs/src/libslic3r/Layer.cpp
index f685906e9..d11f68fb0 100644
--- a/xs/src/libslic3r/Layer.cpp
+++ b/xs/src/libslic3r/Layer.cpp
@@ -13,12 +13,10 @@ Layer::Layer(size_t id, PrintObject *object, coordf_t height, coordf_t print_z,
         coordf_t slice_z)
 :   upper_layer(NULL),
     lower_layer(NULL),
-    regions(),
     slicing_errors(false),
     slice_z(slice_z),
     print_z(print_z),
     height(height),
-    slices(),
     _id(id),
     _object(object)
 {
@@ -38,37 +36,6 @@ Layer::~Layer()
     this->clear_regions();
 }
 
-size_t
-Layer::id() const
-{
-    return this->_id;
-}
-
-void
-Layer::set_id(size_t id)
-{
-    this->_id = id;
-}
-
-PrintObject*
-Layer::object()
-{
-    return this->_object;
-}
-
-const PrintObject*
-Layer::object() const
-{
-    return this->_object;
-}
-
-
-size_t
-Layer::region_count() const
-{
-    return this->regions.size();
-}
-
 void
 Layer::clear_regions()
 {
diff --git a/xs/src/libslic3r/Layer.hpp b/xs/src/libslic3r/Layer.hpp
index 6339434c7..dd0f0143a 100644
--- a/xs/src/libslic3r/Layer.hpp
+++ b/xs/src/libslic3r/Layer.hpp
@@ -15,13 +15,12 @@ class Layer;
 class PrintRegion;
 class PrintObject;
 
-
 // TODO: make stuff private
 class LayerRegion
 {
     friend class Layer;
 
-    public:
+public:
     Layer* layer() { return this->_layer; }
     const Layer* layer() const { return this->_layer; }
     PrintRegion* region() { return this->_region; }
@@ -88,10 +87,10 @@ class Layer {
     friend class PrintObject;
 
 public:
-    size_t id() const;
-    void set_id(size_t id);
-    PrintObject* object();
-    const PrintObject* object() const;
+    size_t id() const { return this->_id; }
+    void set_id(size_t id) { this->_id = id; }
+    PrintObject* object() { return this->_object; }
+    const PrintObject* object() const { return this->_object; }
 
     Layer *upper_layer;
     Layer *lower_layer;
@@ -107,7 +106,7 @@ public:
     // order will be recovered by the G-code generator.
     ExPolygonCollection slices;
 
-    size_t region_count() const;
+    size_t region_count() const { return this->regions.size(); }
     const LayerRegion* get_region(int idx) const { return this->regions.at(idx); }
     LayerRegion* get_region(int idx) { return this->regions.at(idx); }
     LayerRegion* add_region(PrintRegion* print_region);
@@ -129,7 +128,6 @@ protected:
     size_t _id;     // sequential number of layer, 0-based
     PrintObject *_object;
 
-
     Layer(size_t id, PrintObject *object, coordf_t height, coordf_t print_z,
         coordf_t slice_z);
     virtual ~Layer();
diff --git a/xs/src/libslic3r/libslic3r.h b/xs/src/libslic3r/libslic3r.h
index e2c99b00f..4699cc9dc 100644
--- a/xs/src/libslic3r/libslic3r.h
+++ b/xs/src/libslic3r/libslic3r.h
@@ -119,6 +119,14 @@ void append(std::vector<T>& dest, std::vector<T>&& src)
     src.shrink_to_fit();
 }
 
+template <typename T>
+void remove_nulls(std::vector<T*> &vec)
+{
+	vec.erase(
+    	std::remove_if(vec.begin(), vec.end(), [](const T *ptr) { return ptr == nullptr; }),
+    	vec.end());
+}
+
 } // namespace Slic3r
 
 #endif