diff --git a/CI/ci-cppcheck.sh b/CI/ci-cppcheck.sh
index 520ed1be..914376c2 100755
--- a/CI/ci-cppcheck.sh
+++ b/CI/ci-cppcheck.sh
@@ -30,7 +30,7 @@ echo "CPPCHECK Summary"
 echo "=============================================================================="
 echo -e "${NC}"
 
-MAX_COUNT=27
+MAX_COUNT=26
 
 if [ $COUNT -gt $MAX_COUNT ]; then
   echo -e ${WARNING}
diff --git a/cmake/ACGCompiler.cmake b/cmake/ACGCompiler.cmake
index f5260c9b..464d4f49 100644
--- a/cmake/ACGCompiler.cmake
+++ b/cmake/ACGCompiler.cmake
@@ -62,7 +62,7 @@ if (UNIX)
   # add our standard flags for Template inclusion
   list(APPEND ADDITIONAL_CXX_FLAGS          "-DINCLUDE_TEMPLATES" )
   list(APPEND ADDITIONAL_C_FLAGS            "-DINCLUDE_TEMPLATES" )
-
+  
   ################################################################################
   # OS Defines
   ################################################################################  
@@ -108,9 +108,10 @@ if (UNIX)
   list(APPEND ADDITIONAL_C_FLAGS            ${COMPILER_WARNINGS} )
 
 
-  if ("${CMAKE_CXX_COMPILER}" MATCHES ".*clang.*")
+  if ("${CMAKE_CXX_COMPILER}" MATCHES "Clang")
       list(APPEND ADDITIONAL_CXX_FLAGS "-Weverything")
       list(APPEND ADDITIONAL_CXX_FLAGS "-Wno-c++98-compat")
+      list(APPEND ADDITIONAL_CXX_FLAGS "-Wno-c++98-compat-pedantic")
       list(APPEND ADDITIONAL_CXX_FLAGS "-Wno-padded")
       list(APPEND ADDITIONAL_CXX_FLAGS "-Wno-old-style-cast")
       list(APPEND ADDITIONAL_CXX_FLAGS "-Wno-documentation-unknown-command")
@@ -120,7 +121,7 @@ if (UNIX)
       list(APPEND ADDITIONAL_CXX_FLAGS "-Wno-deprecated")
       list(APPEND ADDITIONAL_CXX_FLAGS "-Wno-weak-vtables")
   endif()
-
+  
   ################################################################################
   # STL Vector checks
   ################################################################################
diff --git a/src/OpenMesh/Apps/Decimating/CmdOption.hh b/src/OpenMesh/Apps/Decimating/CmdOption.hh
index 978d32df..0861087d 100644
--- a/src/OpenMesh/Apps/Decimating/CmdOption.hh
+++ b/src/OpenMesh/Apps/Decimating/CmdOption.hh
@@ -74,7 +74,7 @@ public:
   operator T  () const { return val_; }
   //  operator const T& () const { return val_; }
 
-  operator T* () const  { return is_valid() ? &val_ : NULL; }
+  operator T* () const  { return is_valid() ? &val_ : nullptr; }
 
 private:
 
diff --git a/src/OpenMesh/Apps/Decimating/decimaterviewer.cc b/src/OpenMesh/Apps/Decimating/decimaterviewer.cc
index 042f97c6..5edaf767 100644
--- a/src/OpenMesh/Apps/Decimating/decimaterviewer.cc
+++ b/src/OpenMesh/Apps/Decimating/decimaterviewer.cc
@@ -68,7 +68,7 @@ int main(int argc, char **argv)
   
   if ( !QGLFormat::hasOpenGL() ) {
     QString msg = "System has no OpenGL support!";
-    QMessageBox::critical( NULL, "OpenGL", msg + argv[1] );
+    QMessageBox::critical( nullptr, "OpenGL", msg + argv[1] );
     return -1;
   }
 
@@ -103,7 +103,7 @@ int main(int argc, char **argv)
         QString msg = "Cannot read mesh from file:\n '";
         msg += argv[optind];
         msg += "'";
-        QMessageBox::critical( NULL, w.windowTitle(), msg );
+        QMessageBox::critical( nullptr, w.windowTitle(), msg );
         return 1;
      }
   }
@@ -118,7 +118,7 @@ int main(int argc, char **argv)
         msg += "- Mesh file didn't provide texture coordinates\n";
         msg += "- Texture file does not exist\n";
         msg += "- Texture file is not accessible.\n";
-        QMessageBox::warning( NULL, w.windowTitle(), msg );
+        QMessageBox::warning( nullptr, w.windowTitle(), msg );
      }
   }
 
diff --git a/src/OpenMesh/Apps/QtViewer/MeshViewerWidget.cc b/src/OpenMesh/Apps/QtViewer/MeshViewerWidget.cc
index d85b9426..7385e596 100644
--- a/src/OpenMesh/Apps/QtViewer/MeshViewerWidget.cc
+++ b/src/OpenMesh/Apps/QtViewer/MeshViewerWidget.cc
@@ -63,7 +63,7 @@ MeshViewerWidget::MeshViewerWidget(QWidget* parent)  : MeshViewerWidgetT<MyMesh>
         QString msg = "Cannot read mesh from file:\n '";
         msg += fname;
         msg += "'";
-        QMessageBox::critical( NULL, windowTitle(), msg);
+        QMessageBox::critical( nullptr, windowTitle(), msg);
     }
     t.stop();
     std::cout << "Loaded mesh in ~" << t.as_string() << std::endl;
@@ -80,7 +80,7 @@ void MeshViewerWidget::open_texture_gui(QString fname)
         msg += "- Mesh file didn't provide texture coordinates\n";
         msg += "- Texture file does not exist\n";
         msg += "- Texture file is not accessible.\n";
-        QMessageBox::warning( NULL, windowTitle(), msg );
+        QMessageBox::warning( nullptr, windowTitle(), msg );
     }
 }
 
diff --git a/src/OpenMesh/Apps/QtViewer/MeshViewerWidgetT_impl.hh b/src/OpenMesh/Apps/QtViewer/MeshViewerWidgetT_impl.hh
index dc10a9a7..9dda329b 100644
--- a/src/OpenMesh/Apps/QtViewer/MeshViewerWidgetT_impl.hh
+++ b/src/OpenMesh/Apps/QtViewer/MeshViewerWidgetT_impl.hh
@@ -131,7 +131,6 @@ MeshViewerWidgetT<M>::open_mesh(const char* _filename, IO::Options _opt)
     typename Mesh::ConstVertexIter vIt(mesh_.vertices_begin());
     typename Mesh::ConstVertexIter vEnd(mesh_.vertices_end());      
     
-    typedef typename Mesh::Point Point;
     using OpenMesh::Vec3f;
     
     Vec3f bbMin, bbMax;
diff --git a/src/OpenMesh/Apps/Subdivider/SubdivideWidget.cc b/src/OpenMesh/Apps/Subdivider/SubdivideWidget.cc
index 40220942..7434a8b9 100644
--- a/src/OpenMesh/Apps/Subdivider/SubdivideWidget.cc
+++ b/src/OpenMesh/Apps/Subdivider/SubdivideWidget.cc
@@ -87,7 +87,7 @@ using namespace OpenMesh::Subdivider;
 SubdivideWidget::
 SubdivideWidget(QWidget* _parent, const char* _name)
   : QWidget(_parent),
-    timer_(NULL), animate_step_(0), max_animate_steps_(4), msecs_(0)
+    timer_(nullptr), animate_step_(0), max_animate_steps_(4), msecs_(0)
 {
 
   setWindowTitle( QString(_name) );
diff --git a/src/OpenMesh/Apps/Subdivider/qtsubdivider.cc b/src/OpenMesh/Apps/Subdivider/qtsubdivider.cc
index fae98b26..665274dc 100644
--- a/src/OpenMesh/Apps/Subdivider/qtsubdivider.cc
+++ b/src/OpenMesh/Apps/Subdivider/qtsubdivider.cc
@@ -60,7 +60,7 @@ int main(int argc, char **argv)
 
   if ( !QGLFormat::hasOpenGL() ) {
     QString msg = "System has no OpenGL support!";
-    QMessageBox::critical( NULL, "OpenGL", msg + argv[1], QMessageBox::Ok );
+    QMessageBox::critical( nullptr, "OpenGL", msg + argv[1], QMessageBox::Ok );
     return -1;
   }
 
@@ -77,7 +77,7 @@ int main(int argc, char **argv)
      if ( ! w->open_mesh(argv[1]) )
      {
         QString msg = "Cannot read mesh from file ";
-        QMessageBox::critical( NULL, argv[1], msg + argv[1], QMessageBox::Ok );
+        QMessageBox::critical( nullptr, argv[1], msg + argv[1], QMessageBox::Ok );
         return -1;
      }
   }
diff --git a/src/OpenMesh/Apps/Unsupported/IvViewer/SoOpenMeshSupport.hh b/src/OpenMesh/Apps/Unsupported/IvViewer/SoOpenMeshSupport.hh
index c323e0af..7c38018f 100644
--- a/src/OpenMesh/Apps/Unsupported/IvViewer/SoOpenMeshSupport.hh
+++ b/src/OpenMesh/Apps/Unsupported/IvViewer/SoOpenMeshSupport.hh
@@ -78,9 +78,9 @@ PRIVATE_NODE_TYPESYSTEM_SOURCE(_class_); \
 SO_NODE_SOURCE_TEMPLATE \
 unsigned int _class_::classinstances = 0; \
 SO_NODE_SOURCE_TEMPLATE \
-const SoFieldData ** _class_::parentFieldData = NULL; \
+const SoFieldData ** _class_::parentFieldData = nullptr; \
 SO_NODE_SOURCE_TEMPLATE \
-SoFieldData * _class_::fieldData = NULL; \
+SoFieldData * _class_::fieldData = nullptr; \
  \
 SO_NODE_SOURCE_TEMPLATE \
 const SoFieldData ** \
diff --git a/src/OpenMesh/Apps/Unsupported/OsgViewer/meshviewer.cc b/src/OpenMesh/Apps/Unsupported/OsgViewer/meshviewer.cc
index c35867b9..bd127bb1 100644
--- a/src/OpenMesh/Apps/Unsupported/OsgViewer/meshviewer.cc
+++ b/src/OpenMesh/Apps/Unsupported/OsgViewer/meshviewer.cc
@@ -78,7 +78,7 @@ int main(int argc, char **argv)
 
   if ( !QGLFormat::hasOpenGL() ) {
     QString msg = "System has no OpenGL support!";
-    QMessageBox::critical( NULL, "OpenGL", msg + argv[1], 0 );
+    QMessageBox::critical( nullptr, "OpenGL", msg + argv[1], 0 );
     return -1;
   }
 
@@ -115,7 +115,7 @@ int main(int argc, char **argv)
         QString msg = "Cannot read mesh from file:\n '";
         msg += argv[optind];
         msg += "'";
-        QMessageBox::critical( NULL, w->caption(), msg, 0 );
+        QMessageBox::critical( nullptr, w->caption(), msg, 0 );
         return 1;
      }
   }
@@ -130,7 +130,7 @@ int main(int argc, char **argv)
         msg += "- Mesh file didn't provide texture coordinates\n";
         msg += "- Texture file does not exist\n";
         msg += "- Texture file is not accessible.\n";
-        QMessageBox::warning( NULL, w->caption(), msg, 0 );
+        QMessageBox::warning( nullptr, w->caption(), msg, 0 );
      }
   }
 
diff --git a/src/OpenMesh/Apps/Unsupported/OsgViewer/osgviewer.cc b/src/OpenMesh/Apps/Unsupported/OsgViewer/osgviewer.cc
index e7520abb..c23e7174 100644
--- a/src/OpenMesh/Apps/Unsupported/OsgViewer/osgviewer.cc
+++ b/src/OpenMesh/Apps/Unsupported/OsgViewer/osgviewer.cc
@@ -325,7 +325,7 @@ void mouse(int button, int state, int x, int y)
   {
     g.mgr->mouseButtonRelease(button, x, y);
 //     if ( g.mode & FLYMODE )
-//       glutIdleFunc(NULL); 
+//       glutIdleFunc(nullptr); 
   }
   else
   {
diff --git a/src/OpenMesh/Apps/Unsupported/Streaming-qt4/Server/VDPMServerSession.cc b/src/OpenMesh/Apps/Unsupported/Streaming-qt4/Server/VDPMServerSession.cc
index e4af2fdc..b7ad1171 100644
--- a/src/OpenMesh/Apps/Unsupported/Streaming-qt4/Server/VDPMServerSession.cc
+++ b/src/OpenMesh/Apps/Unsupported/Streaming-qt4/Server/VDPMServerSession.cc
@@ -64,7 +64,7 @@ set_vdpm(const char _vdpm_name[256])
   }
 #endif
   vdpm_ = ((VDPMServerViewerWidget *) ((VDPMServerSocket *) parent())->parent())->get_vdpm(_vdpm_name);
-  if (vdpm_ == NULL)
+  if (vdpm_ == nullptr)
     return  false;
 
   vhierarchy_ = &vdpm_->vhierarchy();
diff --git a/src/OpenMesh/Apps/Unsupported/Streaming-qt4/Server/VDPMServerViewerWidget.cc b/src/OpenMesh/Apps/Unsupported/Streaming-qt4/Server/VDPMServerViewerWidget.cc
index cad28022..3fdc6011 100644
--- a/src/OpenMesh/Apps/Unsupported/Streaming-qt4/Server/VDPMServerViewerWidget.cc
+++ b/src/OpenMesh/Apps/Unsupported/Streaming-qt4/Server/VDPMServerViewerWidget.cc
@@ -72,7 +72,7 @@ get_vdpm(const char _vdpm_name[256])
     }
   }
 
-  return  NULL;
+  return  nullptr;
 }
 
 void
diff --git a/src/OpenMesh/Apps/Unsupported/Streaming/Server/VDPMServerSession.cc b/src/OpenMesh/Apps/Unsupported/Streaming/Server/VDPMServerSession.cc
index fa47a34a..dac0b24a 100644
--- a/src/OpenMesh/Apps/Unsupported/Streaming/Server/VDPMServerSession.cc
+++ b/src/OpenMesh/Apps/Unsupported/Streaming/Server/VDPMServerSession.cc
@@ -64,7 +64,7 @@ set_vdpm(const char _vdpm_name[256])
   }
 #endif
   vdpm_ = ((VDPMServerViewerWidget *) ((VDPMServerSocket *) parent())->parent())->get_vdpm(_vdpm_name);
-  if (vdpm_ == NULL)
+  if (vdpm_ == nullptr)
     return  false;
 
   vhierarchy_ = &vdpm_->vhierarchy();
diff --git a/src/OpenMesh/Apps/Unsupported/Streaming/Server/VDPMServerViewerWidget.cc b/src/OpenMesh/Apps/Unsupported/Streaming/Server/VDPMServerViewerWidget.cc
index 84eb92eb..2d4e0532 100644
--- a/src/OpenMesh/Apps/Unsupported/Streaming/Server/VDPMServerViewerWidget.cc
+++ b/src/OpenMesh/Apps/Unsupported/Streaming/Server/VDPMServerViewerWidget.cc
@@ -71,7 +71,7 @@ get_vdpm(const char _vdpm_name[256])
     }
   }
 
-  return  NULL;
+  return  nullptr;
 }
 
 void
diff --git a/src/OpenMesh/Apps/VDProgMesh/mkbalancedpm/mkbalancedpm.cc b/src/OpenMesh/Apps/VDProgMesh/mkbalancedpm/mkbalancedpm.cc
index ae3e7077..77b7dae6 100644
--- a/src/OpenMesh/Apps/VDProgMesh/mkbalancedpm/mkbalancedpm.cc
+++ b/src/OpenMesh/Apps/VDProgMesh/mkbalancedpm/mkbalancedpm.cc
@@ -114,7 +114,7 @@ public: // inherited
     n_roots_    = calc_bits_for_roots(n_vertices_);
   }
 
-  virtual float collapse_priority(const CollapseInfo& _ci)
+  virtual float collapse_priority(const CollapseInfo& _ci) override
   {
     level_t newlevel = std::max( BaseModQ::mesh().property( level_, _ci.v0 ),
                                  BaseModQ::mesh().property( level_, _ci.v1 ) )+1;
@@ -135,7 +135,7 @@ public: // inherited
   }
 
   /// post-process halfedge collapse (accumulate quadrics)
-  void postprocess_collapse(const CollapseInfo& _ci)
+  void postprocess_collapse(const CollapseInfo& _ci) override
   {
     BaseModQ::postprocess_collapse( _ci );
 
diff --git a/src/OpenMesh/Core/IO/IOManager.cc b/src/OpenMesh/Core/IO/IOManager.cc
index 454edb2a..8b3a4193 100644
--- a/src/OpenMesh/Core/IO/IOManager.cc
+++ b/src/OpenMesh/Core/IO/IOManager.cc
@@ -258,7 +258,7 @@ find_writer(const std::string& _format)
     if ((*it)->can_u_write(filename))
       return *it;
 
-  return NULL;
+  return nullptr;
 }
 
 
diff --git a/src/OpenMesh/Core/IO/OMFormat.cc b/src/OpenMesh/Core/IO/OMFormat.cc
index 6511e3e2..97175088 100644
--- a/src/OpenMesh/Core/IO/OMFormat.cc
+++ b/src/OpenMesh/Core/IO/OMFormat.cc
@@ -135,7 +135,7 @@ namespace OMFormat {
       default:
 	std::clog << "as_string(Chunk::Entity): Invalid value!";
     }
-    return NULL;
+    return nullptr;
   }
 
 
@@ -153,7 +153,7 @@ namespace OMFormat {
       case Chunk::Type_Custom:   return "Custom";
       case Chunk::Type_Topology: return "Topology";
     }
-    return NULL;
+    return nullptr;
   }
 
 
@@ -172,7 +172,7 @@ namespace OMFormat {
       case Chunk::Dim_7D: return "7D";
       case Chunk::Dim_8D: return "8D";
     }
-    return NULL;
+    return nullptr;
   }
 
 
@@ -187,7 +187,7 @@ namespace OMFormat {
       case Chunk::Integer_32 : return "32";
       case Chunk::Integer_64 : return "64";
     }
-    return NULL;
+    return nullptr;
   }
 
   const char *as_string(Chunk::Float_Size d)
@@ -198,7 +198,7 @@ namespace OMFormat {
       case Chunk::Float_64 : return "64";
       case Chunk::Float_128: return "128";
     }
-    return NULL;
+    return nullptr;
   }
 
 
diff --git a/src/OpenMesh/Core/IO/exporter/BaseExporter.hh b/src/OpenMesh/Core/IO/exporter/BaseExporter.hh
index 9903a851..86290720 100644
--- a/src/OpenMesh/Core/IO/exporter/BaseExporter.hh
+++ b/src/OpenMesh/Core/IO/exporter/BaseExporter.hh
@@ -144,7 +144,7 @@ public:
   virtual OpenMesh::Attributes::StatusInfo  status(HalfedgeHandle _heh) const = 0;
 
   // get reference to base kernel
-  virtual const BaseKernel* kernel() { return 0; }
+  virtual const BaseKernel* kernel() { return nullptr; }
 
 
   // query number of faces, vertices, normals, texcoords
diff --git a/src/OpenMesh/Core/IO/importer/BaseImporter.hh b/src/OpenMesh/Core/IO/importer/BaseImporter.hh
index 3513e279..ff86dadd 100644
--- a/src/OpenMesh/Core/IO/importer/BaseImporter.hh
+++ b/src/OpenMesh/Core/IO/importer/BaseImporter.hh
@@ -196,7 +196,7 @@ public:
   virtual void add_texture_information( int _id , std::string _name ) = 0;
 
   // get reference to base kernel
-  virtual BaseKernel* kernel() { return 0; }
+  virtual BaseKernel* kernel() { return nullptr; }
 
   virtual bool is_triangle_mesh()     const { return false; }
 
diff --git a/src/OpenMesh/Core/IO/reader/BaseReader.hh b/src/OpenMesh/Core/IO/reader/BaseReader.hh
index 6361bfd3..9f6c23bb 100644
--- a/src/OpenMesh/Core/IO/reader/BaseReader.hh
+++ b/src/OpenMesh/Core/IO/reader/BaseReader.hh
@@ -48,10 +48,7 @@
 //
 //=============================================================================
 
-
-#ifndef __BASEREADER_HH__
-#define __BASEREADER_HH__
-
+#pragma once
 
 //=== INCLUDES ================================================================
 
@@ -91,7 +88,7 @@ class OPENMESHDLLEXPORT BaseReader
 public:
 
   /// Destructor
-  virtual ~BaseReader() {};
+  virtual ~BaseReader() {}
 
   /// Returns a brief description of the file type that can be parsed.
   virtual std::string get_description() const = 0;
@@ -204,5 +201,3 @@ static inline std::string &trim(std::string &_string) {
 } // namespace IO
 } // namespace OpenMesh
 //=============================================================================
-#endif
-//=============================================================================
diff --git a/src/OpenMesh/Core/IO/reader/OFFReader.hh b/src/OpenMesh/Core/IO/reader/OFFReader.hh
index 25717b6f..2efe6e4a 100644
--- a/src/OpenMesh/Core/IO/reader/OFFReader.hh
+++ b/src/OpenMesh/Core/IO/reader/OFFReader.hh
@@ -48,10 +48,7 @@
 //
 //=============================================================================
 
-
-#ifndef __OFFREADER_HH__
-#define __OFFREADER_HH__
-
+#pragma once
 
 //=== INCLUDES ================================================================
 
@@ -162,5 +159,3 @@ OPENMESHDLLEXPORT _OFFReader_& OFFReader();
 } // namespace IO
 } // namespace OpenMesh
 //=============================================================================
-#endif
-//=============================================================================
diff --git a/src/OpenMesh/Core/Mesh/BaseKernel.cc b/src/OpenMesh/Core/Mesh/BaseKernel.cc
index 1a375cec..1cdd9cf3 100644
--- a/src/OpenMesh/Core/Mesh/BaseKernel.cc
+++ b/src/OpenMesh/Core/Mesh/BaseKernel.cc
@@ -64,27 +64,27 @@ void BaseKernel::property_stats(std::ostream& _ostr) const
   _ostr << vprops_.size() << " vprops:\n";
   for (it=vps.begin(); it!=vps.end(); ++it)
   {
-    *it == NULL ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
+    *it == nullptr ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
   }
   _ostr << hprops_.size() << " hprops:\n";
   for (it=hps.begin(); it!=hps.end(); ++it)
   {
-    *it == NULL ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
+    *it == nullptr ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
   }
   _ostr << eprops_.size() << " eprops:\n";
   for (it=eps.begin(); it!=eps.end(); ++it)
   {
-    *it == NULL ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
+    *it == nullptr ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
   }
   _ostr << fprops_.size() << " fprops:\n";
   for (it=fps.begin(); it!=fps.end(); ++it)
   {
-    *it == NULL ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
+    *it == nullptr ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
   }
   _ostr << mprops_.size() << " mprops:\n";
   for (it=mps.begin(); it!=mps.end(); ++it)
   {
-    *it == NULL ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
+    *it == nullptr ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
   }
 }
 
@@ -97,7 +97,7 @@ void BaseKernel::vprop_stats( std::string& _string ) const
   PropertyContainer::Properties::const_iterator it;
   const PropertyContainer::Properties& vps = vprops_.properties();
   for (it=vps.begin(); it!=vps.end(); ++it)
-    if ( *it == NULL )
+    if ( *it == nullptr )
       _string += "[deleted] \n";
     else {
       _string += (*it)->name();
@@ -113,7 +113,7 @@ void BaseKernel::hprop_stats( std::string& _string ) const
   PropertyContainer::Properties::const_iterator it;
   const PropertyContainer::Properties& hps = hprops_.properties();
   for (it=hps.begin(); it!=hps.end(); ++it)
-    if ( *it == NULL )
+    if ( *it == nullptr )
       _string += "[deleted] \n";
     else {
       _string += (*it)->name();
@@ -129,7 +129,7 @@ void BaseKernel::eprop_stats( std::string& _string ) const
   PropertyContainer::Properties::const_iterator it;
   const PropertyContainer::Properties& eps = eprops_.properties();
   for (it=eps.begin(); it!=eps.end(); ++it)
-    if ( *it == NULL )
+    if ( *it == nullptr )
       _string += "[deleted] \n";
     else {
       _string += (*it)->name();
@@ -144,7 +144,7 @@ void BaseKernel::fprop_stats( std::string& _string ) const
   PropertyContainer::Properties::const_iterator it;
   const PropertyContainer::Properties& fps = fprops_.properties();
   for (it=fps.begin(); it!=fps.end(); ++it)
-    if ( *it == NULL )
+    if ( *it == nullptr )
       _string += "[deleted] \n";
     else {
       _string += (*it)->name();
@@ -160,7 +160,7 @@ void BaseKernel::mprop_stats( std::string& _string ) const
   PropertyContainer::Properties::const_iterator it;
   const PropertyContainer::Properties& mps = mprops_.properties();
   for (it=mps.begin(); it!=mps.end(); ++it)
-    if ( *it == NULL )
+    if ( *it == nullptr )
       _string += "[deleted] \n";
     else {
       _string += (*it)->name();
@@ -178,7 +178,7 @@ void BaseKernel::vprop_stats(std::ostream& _ostr ) const
   PropertyContainer::Properties::const_iterator it;
   const PropertyContainer::Properties& vps = vprops_.properties();
   for (it=vps.begin(); it!=vps.end(); ++it)
-    *it == NULL ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
+    *it == nullptr ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
 
 }
 void BaseKernel::hprop_stats() const
@@ -190,7 +190,7 @@ void BaseKernel::hprop_stats(std::ostream& _ostr ) const
   PropertyContainer::Properties::const_iterator it;
   const PropertyContainer::Properties& hps = hprops_.properties();
   for (it=hps.begin(); it!=hps.end(); ++it)
-    *it == NULL ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
+    *it == nullptr ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
 
 }
 void BaseKernel::eprop_stats() const
@@ -202,7 +202,7 @@ void BaseKernel::eprop_stats(std::ostream& _ostr ) const
   PropertyContainer::Properties::const_iterator it;
   const PropertyContainer::Properties& eps = eprops_.properties();
   for (it=eps.begin(); it!=eps.end(); ++it)
-    *it == NULL ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
+    *it == nullptr ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
 
 }
 void BaseKernel::fprop_stats() const
@@ -214,7 +214,7 @@ void BaseKernel::fprop_stats(std::ostream& _ostr ) const
   PropertyContainer::Properties::const_iterator it;
   const PropertyContainer::Properties& fps = fprops_.properties();
   for (it=fps.begin(); it!=fps.end(); ++it)
-    *it == NULL ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
+    *it == nullptr ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
 
 }
 void BaseKernel::mprop_stats() const
@@ -226,7 +226,7 @@ void BaseKernel::mprop_stats(std::ostream& _ostr ) const
   PropertyContainer::Properties::const_iterator it;
   const PropertyContainer::Properties& mps = mprops_.properties();
   for (it=mps.begin(); it!=mps.end(); ++it)
-    *it == NULL ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
+    *it == nullptr ? (void)(_ostr << "[deleted]" << "\n") : (*it)->stats(_ostr);
 
 }
 
diff --git a/src/OpenMesh/Core/System/mostream.hh b/src/OpenMesh/Core/System/mostream.hh
index 5463750d..e774d7bc 100644
--- a/src/OpenMesh/Core/System/mostream.hh
+++ b/src/OpenMesh/Core/System/mostream.hh
@@ -285,7 +285,7 @@ class mostream : public std::ostream
 public:
 
   /// Explicit constructor
-  explicit mostream() : std::ostream(NULL) { init(&streambuffer_); }
+  explicit mostream() : std::ostream(nullptr) { init(&streambuffer_); }
 
 
   /// Connect target to multiplexer
diff --git a/src/OpenMesh/Core/Utils/AutoPropertyHandleT.hh b/src/OpenMesh/Core/Utils/AutoPropertyHandleT.hh
index f9b157af..19afb46e 100644
--- a/src/OpenMesh/Core/Utils/AutoPropertyHandleT.hh
+++ b/src/OpenMesh/Core/Utils/AutoPropertyHandleT.hh
@@ -70,7 +70,7 @@ protected:
 
 public:
   AutoPropertyHandleT()
-  : m_(NULL), own_property_(false)
+  : m_(nullptr), own_property_(false)
   {}
   
   AutoPropertyHandleT(const Self& _other)
diff --git a/src/OpenMesh/Core/Utils/Property.hh b/src/OpenMesh/Core/Utils/Property.hh
index cda3f9bf..629225c6 100644
--- a/src/OpenMesh/Core/Utils/Property.hh
+++ b/src/OpenMesh/Core/Utils/Property.hh
@@ -363,7 +363,7 @@ public:
   }
 
   /// Make a copy of self.
-  PropertyT<bool>* clone() const
+  PropertyT<bool>* clone() const override
   {
     PropertyT<bool>* p = new PropertyT<bool>( *this );
     return p;
@@ -434,7 +434,7 @@ public:
 
   const value_type* data() const {
       if( data_.empty() )
-	  return 0;
+	  return nullptr;
 
       return (value_type*) &data_[0];
   }
@@ -451,7 +451,7 @@ public:
     return ((value_type*) &data_[0])[_idx];
   }
 
-  PropertyT<value_type>* clone() const {
+  PropertyT<value_type>* clone() const override {
     PropertyT<value_type>* p = new PropertyT<value_type>( *this );
     return p;
   }
diff --git a/src/OpenMesh/Core/Utils/PropertyContainer.hh b/src/OpenMesh/Core/Utils/PropertyContainer.hh
index fd5a5fad..dcc9a3ac 100644
--- a/src/OpenMesh/Core/Utils/PropertyContainer.hh
+++ b/src/OpenMesh/Core/Utils/PropertyContainer.hh
@@ -102,8 +102,8 @@ public:
   {
     Properties::iterator p_it=properties_.begin(), p_end=properties_.end();
     int idx=0;
-    for ( ; p_it!=p_end && *p_it!=NULL; ++p_it, ++idx ) {};
-    if (p_it==p_end) properties_.push_back(NULL);
+    for ( ; p_it!=p_end && *p_it!=nullptr; ++p_it, ++idx ) {};
+    if (p_it==p_end) properties_.push_back(nullptr);
     properties_[idx] = new PropertyT<T>(_name);
     return BasePropHandleT<T>(idx);
   }
@@ -115,11 +115,11 @@ public:
     Properties::const_iterator p_it = properties_.begin();
     for (int idx=0; p_it != properties_.end(); ++p_it, ++idx)
     {
-      if (*p_it != NULL &&
+      if (*p_it != nullptr &&
          (*p_it)->name() == _name  //skip deleted properties
 // Skip type check
 #ifndef OM_FORCE_STATIC_CAST
-          && dynamic_cast<PropertyT<T>*>(properties_[idx]) != NULL //check type
+          && dynamic_cast<PropertyT<T>*>(properties_[idx]) != nullptr //check type
 #endif
          )
       {
@@ -134,23 +134,23 @@ public:
     Properties::const_iterator p_it = properties_.begin();
     for (int idx=0; p_it != properties_.end(); ++p_it, ++idx)
     {
-      if (*p_it != NULL && (*p_it)->name() == _name) //skip deleted properties
+      if (*p_it != nullptr && (*p_it)->name() == _name) //skip deleted properties
       {
         return *p_it;
       }
     }
-    return NULL;
+    return nullptr;
   }
 
   template <class T> PropertyT<T>& property(BasePropHandleT<T> _h)
   {
     assert(_h.idx() >= 0 && _h.idx() < (int)properties_.size());
-    assert(properties_[_h.idx()] != NULL);
+    assert(properties_[_h.idx()] != nullptr);
 #ifdef OM_FORCE_STATIC_CAST
     return *static_cast  <PropertyT<T>*> (properties_[_h.idx()]);
 #else
     PropertyT<T>* p = dynamic_cast<PropertyT<T>*>(properties_[_h.idx()]);
-    assert(p != NULL);
+    assert(p != nullptr);
     return *p;
 #endif
   }
@@ -159,12 +159,12 @@ public:
   template <class T> const PropertyT<T>& property(BasePropHandleT<T> _h) const
   {
     assert(_h.idx() >= 0 && _h.idx() < (int)properties_.size());
-    assert(properties_[_h.idx()] != NULL);
+    assert(properties_[_h.idx()] != nullptr);
 #ifdef OM_FORCE_STATIC_CAST
     return *static_cast<PropertyT<T>*>(properties_[_h.idx()]);
 #else
     PropertyT<T>* p = dynamic_cast<PropertyT<T>*>(properties_[_h.idx()]);
-    assert(p != NULL);
+    assert(p != nullptr);
     return *p;
 #endif
   }
@@ -174,7 +174,7 @@ public:
   {
     assert(_h.idx() >= 0 && _h.idx() < (int)properties_.size());
     delete properties_[_h.idx()];
-    properties_[_h.idx()] = NULL;
+    properties_[_h.idx()] = nullptr;
   }
 
 
@@ -281,8 +281,8 @@ protected: // generic add/get
   {
     Properties::iterator p_it=properties_.begin(), p_end=properties_.end();
     size_t idx=0;
-    for (; p_it!=p_end && *p_it!=NULL; ++p_it, ++idx) {};
-    if (p_it==p_end) properties_.push_back(NULL);
+    for (; p_it!=p_end && *p_it!=nullptr; ++p_it, ++idx) {};
+    if (p_it==p_end) properties_.push_back(nullptr);
     properties_[idx] = _bp;
     return idx;
   }
@@ -290,18 +290,18 @@ protected: // generic add/get
   BaseProperty& _property( size_t _idx )
   {
     assert( _idx < properties_.size());
-    assert( properties_[_idx] != NULL);
+    assert( properties_[_idx] != nullptr);
     BaseProperty *p = properties_[_idx];
-    assert( p != NULL );
+    assert( p != nullptr );
     return *p;
   }
 
   const BaseProperty& _property( size_t _idx ) const
   {
     assert( _idx < properties_.size());
-    assert( properties_[_idx] != NULL);
+    assert( properties_[_idx] != nullptr);
     BaseProperty *p = properties_[_idx];
-    assert( p != NULL );
+    assert( p != nullptr );
     return *p;
   }
 
diff --git a/src/OpenMesh/Core/Utils/SingletonT.hh b/src/OpenMesh/Core/Utils/SingletonT.hh
index 2945debb..438cd655 100644
--- a/src/OpenMesh/Core/Utils/SingletonT.hh
+++ b/src/OpenMesh/Core/Utils/SingletonT.hh
@@ -48,10 +48,7 @@
 //
 //=============================================================================
 
-
-#ifndef __SINGLETON_HH__
-#define __SINGLETON_HH__
-
+#pragma once
 
 //=== INCLUDES ================================================================
 
@@ -145,5 +142,3 @@ private:
 #  include "SingletonT_impl.hh"
 #endif
 //=============================================================================
-#endif // __SINGLETON_HH__
-//=============================================================================
diff --git a/src/OpenMesh/Tools/Decimater/BaseDecimaterT_impl.hh b/src/OpenMesh/Tools/Decimater/BaseDecimaterT_impl.hh
index 780dfa34..68d57b09 100644
--- a/src/OpenMesh/Tools/Decimater/BaseDecimaterT_impl.hh
+++ b/src/OpenMesh/Tools/Decimater/BaseDecimaterT_impl.hh
@@ -67,7 +67,7 @@ namespace Decimater {
 
 template<class Mesh>
 BaseDecimaterT<Mesh>::BaseDecimaterT(Mesh& _mesh) :
-    mesh_(_mesh), cmodule_(NULL), initialized_(false), observer_(NULL) {
+    mesh_(_mesh), cmodule_(nullptr), initialized_(false), observer_(nullptr) {
   // default properties
   mesh_.request_vertex_status();
   mesh_.request_edge_status();
@@ -249,8 +249,8 @@ bool BaseDecimaterT<Mesh>::initialize() {
   // priority module explicitly.
 
   // find the priority module: either the only non-binary module in the list, or "Quadric"
-  Module *quadric = NULL;
-  Module *pmodule = NULL;
+  Module *quadric = nullptr;
+  Module *pmodule = nullptr;
   for (ModuleListIterator m_it = all_modules_.begin(), m_end =
       all_modules_.end(); m_it != m_end; ++m_it) {
     if ((*m_it)->name() == "Quadric")
diff --git a/src/OpenMesh/Tools/Decimater/DecimaterT_impl.hh b/src/OpenMesh/Tools/Decimater/DecimaterT_impl.hh
index 7f61a777..e7211a0c 100644
--- a/src/OpenMesh/Tools/Decimater/DecimaterT_impl.hh
+++ b/src/OpenMesh/Tools/Decimater/DecimaterT_impl.hh
@@ -75,7 +75,7 @@ DecimaterT<Mesh>::DecimaterT(Mesh& _mesh) :
 #if (defined(_MSC_VER) && (_MSC_VER >= 1800)) || __cplusplus > 199711L || defined( __GXX_EXPERIMENTAL_CXX0X__ )
   heap_(nullptr)
 #else
-  heap_(NULL)
+  heap_(nullptr)
 #endif
 
 {
diff --git a/src/OpenMesh/Tools/Decimater/ModAspectRatioT.hh b/src/OpenMesh/Tools/Decimater/ModAspectRatioT.hh
index 4977fa6d..0213cbbb 100644
--- a/src/OpenMesh/Tools/Decimater/ModAspectRatioT.hh
+++ b/src/OpenMesh/Tools/Decimater/ModAspectRatioT.hh
@@ -111,16 +111,16 @@ class ModAspectRatioT: public ModBaseT<MeshT> {
     }
 
     /// precompute face aspect ratio
-    void initialize();
+    void initialize() override;
 
     /// Returns the collapse priority
-    float collapse_priority(const CollapseInfo& _ci);
+    float collapse_priority(const CollapseInfo& _ci) override;
 
     /// update aspect ratio of one-ring
-    void preprocess_collapse(const CollapseInfo& _ci);
+    void preprocess_collapse(const CollapseInfo& _ci) override;
 
     /// set percentage of aspect ratio
-    void set_error_tolerance_factor(double _factor);
+    void set_error_tolerance_factor(double _factor) override;
 
   private:
 
diff --git a/src/OpenMesh/Tools/Decimater/ModBaseT.hh b/src/OpenMesh/Tools/Decimater/ModBaseT.hh
index d972cda6..f89e907e 100644
--- a/src/OpenMesh/Tools/Decimater/ModBaseT.hh
+++ b/src/OpenMesh/Tools/Decimater/ModBaseT.hh
@@ -90,14 +90,14 @@ public:
 public:
 
   /// Default constructor
-  ModHandleT() : mod_(NULL) {}
+  ModHandleT() : mod_(nullptr) {}
 
   /// Destructor
   ~ModHandleT() { /* don't delete mod_, since handle is not owner! */ }
 
   /// Check handle status
   /// \return \c true, if handle is valid, else \c false.
-  bool is_valid() const { return mod_ != NULL; }
+  bool is_valid() const { return mod_ != nullptr; }
 
 private:
 
@@ -107,7 +107,7 @@ private:
   template <typename Mesh> friend class BaseDecimaterT;
 #endif
 
-  void     clear()           { mod_ = NULL; }
+  void     clear()           { mod_ = nullptr; }
   void     init(Module* _m)  { mod_ = _m;   }
   Module*  module()          { return mod_; }
 
@@ -128,7 +128,7 @@ private:
 /// Macro that sets up the name() function
 /// \internal
 #define DECIMATER_MODNAME(_mod_name) \
- virtual const std::string& name() const { \
+ virtual const std::string& name() const override { \
   static std::string _s_modname_(#_mod_name); return _s_modname_; \
 }
 
@@ -212,8 +212,8 @@ public:
   /// Virtual desctructor
   virtual ~ModBaseT() { }
 
-  /// Set module's name (using DECIMATER_MODNAME macro)
-  DECIMATER_MODNAME(ModBase);
+  /// Set module's name
+  virtual const std::string& name() const { static std::string _s_modname_("ModBase"); return _s_modname_; }
 
 
   /// Returns true if criteria returns a binary value.
diff --git a/src/OpenMesh/Tools/Decimater/ModEdgeLengthT.hh b/src/OpenMesh/Tools/Decimater/ModEdgeLengthT.hh
index 4b7ec155..e8e75a39 100644
--- a/src/OpenMesh/Tools/Decimater/ModEdgeLengthT.hh
+++ b/src/OpenMesh/Tools/Decimater/ModEdgeLengthT.hh
@@ -98,10 +98,10 @@ class ModEdgeLengthT: public ModBaseT<MeshT> {
      Cont. mode:  Collapse smallest edge first, but
      don't collapse edges longer as edge_length_
      */
-    float collapse_priority(const CollapseInfo& _ci);
+    float collapse_priority(const CollapseInfo& _ci) override;
 
     /// set the percentage of edge length
-    void set_error_tolerance_factor(double _factor);
+    void set_error_tolerance_factor(double _factor) override;
 
   private:
 
diff --git a/src/OpenMesh/Tools/Decimater/ModHausdorffT.hh b/src/OpenMesh/Tools/Decimater/ModHausdorffT.hh
index 7d7d040b..74c76373 100644
--- a/src/OpenMesh/Tools/Decimater/ModHausdorffT.hh
+++ b/src/OpenMesh/Tools/Decimater/ModHausdorffT.hh
@@ -108,7 +108,7 @@ class ModHausdorffT: public ModBaseT<MeshT> {
     }
 
     /// reset per-face point lists
-    virtual void initialize();
+    virtual void initialize() override;
 
     /** \brief compute Hausdorff error for one-ring
      *
@@ -120,13 +120,13 @@ class ModHausdorffT: public ModBaseT<MeshT> {
      * @return Binary return, if collapse is legal or illegal
      */
 
-    virtual float collapse_priority(const CollapseInfo& _ci);
+    virtual float collapse_priority(const CollapseInfo& _ci) override;
 
     /// re-distribute points
-    virtual void postprocess_collapse(const CollapseInfo& _ci);
+    virtual void postprocess_collapse(const CollapseInfo& _ci) override;
 
     /// set the percentage of tolerance
-    void set_error_tolerance_factor(double _factor);
+    void set_error_tolerance_factor(double _factor) override;
 
   private:
 
diff --git a/src/OpenMesh/Tools/Decimater/ModIndependentSetsT.hh b/src/OpenMesh/Tools/Decimater/ModIndependentSetsT.hh
index c7c4895c..7a416af7 100644
--- a/src/OpenMesh/Tools/Decimater/ModIndependentSetsT.hh
+++ b/src/OpenMesh/Tools/Decimater/ModIndependentSetsT.hh
@@ -77,7 +77,7 @@ class ModIndependentSetsT: public ModBaseT<MeshT> {
     }
 
     /// override
-    void postprocess_collapse(const CollapseInfo& _ci) {
+    void postprocess_collapse(const CollapseInfo& _ci) override {
       typename Mesh::VertexVertexIter vv_it;
 
       Base::mesh().status(_ci.v1).set_locked(true);
diff --git a/src/OpenMesh/Tools/Decimater/ModNormalDeviationT.hh b/src/OpenMesh/Tools/Decimater/ModNormalDeviationT.hh
index 1c11a93c..9966d826 100644
--- a/src/OpenMesh/Tools/Decimater/ModNormalDeviationT.hh
+++ b/src/OpenMesh/Tools/Decimater/ModNormalDeviationT.hh
@@ -140,7 +140,7 @@ public:
 
 
   /// Allocate and init normal cones
-  void  initialize() {
+  void  initialize() override {
     if (!normal_cones_.is_valid())
       mesh_.add_property(normal_cones_);
 
@@ -165,7 +165,7 @@ public:
    * @param _ci Collapse info data
    * @return Half of the normal cones size (radius in radians)
    */
-  float collapse_priority(const CollapseInfo& _ci) {
+  float collapse_priority(const CollapseInfo& _ci) override {
     // simulate collapse
     mesh_.set_point(_ci.v0, _ci.p1);
 
@@ -203,7 +203,7 @@ public:
   }
 
   /// set the percentage of normal deviation
-  void set_error_tolerance_factor(double _factor) {
+  void set_error_tolerance_factor(double _factor) override {
     if (_factor >= 0.0 && _factor <= 1.0) {
       // the smaller the factor, the smaller normal_deviation_ gets
       // thus creating a stricter constraint
@@ -216,7 +216,7 @@ public:
   }
 
 
-  void  postprocess_collapse(const CollapseInfo& _ci) {
+  void  postprocess_collapse(const CollapseInfo& _ci) override {
     // account for changed normals
     typename Mesh::VertexFaceIter vf_it(mesh_, _ci.v1);
     for (; vf_it.is_valid(); ++vf_it)
diff --git a/src/OpenMesh/Tools/Decimater/ModNormalFlippingT.hh b/src/OpenMesh/Tools/Decimater/ModNormalFlippingT.hh
index 9833e182..b2a00fd3 100644
--- a/src/OpenMesh/Tools/Decimater/ModNormalFlippingT.hh
+++ b/src/OpenMesh/Tools/Decimater/ModNormalFlippingT.hh
@@ -122,7 +122,7 @@ public:
    *
    *  \see set_max_normal_deviation()
    */
-  float collapse_priority(const CollapseInfo& _ci)
+  float collapse_priority(const CollapseInfo& _ci) override
   {
     // simulate collapse
     Base::mesh().set_point(_ci.v0, _ci.p1);
@@ -154,7 +154,7 @@ public:
   }
 
   /// set the percentage of maximum normal deviation
-  void set_error_tolerance_factor(double _factor) {
+  void set_error_tolerance_factor(double _factor) override {
     if (_factor >= 0.0 && _factor <= 1.0) {
       // the smaller the factor, the smaller max_deviation_ gets
       // thus creating a stricter constraint
diff --git a/src/OpenMesh/Tools/Decimater/ModProgMeshT.hh b/src/OpenMesh/Tools/Decimater/ModProgMeshT.hh
index 43c02982..dbedc07c 100644
--- a/src/OpenMesh/Tools/Decimater/ModProgMeshT.hh
+++ b/src/OpenMesh/Tools/Decimater/ModProgMeshT.hh
@@ -130,7 +130,7 @@ public: // inherited
 
   /// Stores collapse information in a queue.
   /// \see infolist()
-  void postprocess_collapse(const CollapseInfo& _ci)
+  void postprocess_collapse(const CollapseInfo& _ci) override
   {
     pmi_.push_back( Info( _ci ) );
   }
diff --git a/src/OpenMesh/Tools/Decimater/ModQuadricT.hh b/src/OpenMesh/Tools/Decimater/ModQuadricT.hh
index 444c1098..2f431bf4 100644
--- a/src/OpenMesh/Tools/Decimater/ModQuadricT.hh
+++ b/src/OpenMesh/Tools/Decimater/ModQuadricT.hh
@@ -110,7 +110,7 @@ public: // inherited
    *  \see ModBaseT::collapse_priority() for return values
    *  \see set_max_err()
    */
-  virtual float collapse_priority(const CollapseInfo& _ci)
+  virtual float collapse_priority(const CollapseInfo& _ci) override
   {
     using namespace OpenMesh;
 
@@ -131,7 +131,7 @@ public: // inherited
 
 
   /// Post-process halfedge collapse (accumulate quadrics)
-  virtual void postprocess_collapse(const CollapseInfo& _ci)
+  virtual void postprocess_collapse(const CollapseInfo& _ci) override
   {
     Base::mesh().property(quadrics_, _ci.v1) +=
       Base::mesh().property(quadrics_, _ci.v0);
diff --git a/src/OpenMesh/Tools/Decimater/ModRoundnessT.hh b/src/OpenMesh/Tools/Decimater/ModRoundnessT.hh
index 5b3c1485..afd5ade4 100644
--- a/src/OpenMesh/Tools/Decimater/ModRoundnessT.hh
+++ b/src/OpenMesh/Tools/Decimater/ModRoundnessT.hh
@@ -117,7 +117,7 @@ class ModRoundnessT : public ModBaseT<MeshT>
    * \return LEGAL_COLLAPSE or ILLEGAL_COLLAPSE in binary mode
    * \see set_min_roundness()
    */
-  float collapse_priority(const CollapseInfo& _ci)
+  float collapse_priority(const CollapseInfo& _ci) override
   {
     //     using namespace OpenMesh;
 
@@ -174,7 +174,7 @@ class ModRoundnessT : public ModBaseT<MeshT>
   }
 
   /// set the percentage of minimum roundness
-  void set_error_tolerance_factor(double _factor) {
+  void set_error_tolerance_factor(double _factor) override {
     if (this->is_binary()) {
       if (_factor >= 0.0 && _factor <= 1.0) {
         // the smaller the factor, the smaller min_r_ gets
diff --git a/src/OpenMesh/Tools/Kernel_OSG/PropertyT.hh b/src/OpenMesh/Tools/Kernel_OSG/PropertyT.hh
index 47990e58..cd0680f9 100644
--- a/src/OpenMesh/Tools/Kernel_OSG/PropertyT.hh
+++ b/src/OpenMesh/Tools/Kernel_OSG/PropertyT.hh
@@ -108,7 +108,7 @@ public:
 
   //
   oPropertyT( const std::string& _name = "<unknown>" )
-    : BaseProperty(_name), data_(NULL)
+    : BaseProperty(_name), data_(nullptr)
   {
     data_ = property_t::create();
     
diff --git a/src/OpenMesh/Tools/Subdivider/Adaptive/Composite/CompositeT.hh b/src/OpenMesh/Tools/Subdivider/Adaptive/Composite/CompositeT.hh
index 2d5d0c35..b9298263 100644
--- a/src/OpenMesh/Tools/Subdivider/Adaptive/Composite/CompositeT.hh
+++ b/src/OpenMesh/Tools/Subdivider/Adaptive/Composite/CompositeT.hh
@@ -148,7 +148,7 @@ public:
   /// Constructor
   explicit CompositeT(Mesh& _mesh)
     : subdiv_type_(0), 
-      subdiv_rule_(NULL), /*first_rule_(NULL), last_rule_(NULL),*/ mesh_(_mesh)
+      subdiv_rule_(nullptr), /*first_rule_(nullptr), last_rule_(nullptr),*/ mesh_(_mesh)
   { }
 
   ///
@@ -161,7 +161,7 @@ public:
   void cleanup(void)
   {
     subdiv_type_ = 0;
-    subdiv_rule_ = NULL;
+    subdiv_rule_ = nullptr;
 
     std::for_each(rule_sequence_.begin(), 
                   rule_sequence_.end(), DeleteRule() );
diff --git a/src/OpenMesh/Tools/Subdivider/Adaptive/Composite/RulesT.hh b/src/OpenMesh/Tools/Subdivider/Adaptive/Composite/RulesT.hh
index 576193de..2c2e7679 100644
--- a/src/OpenMesh/Tools/Subdivider/Adaptive/Composite/RulesT.hh
+++ b/src/OpenMesh/Tools/Subdivider/Adaptive/Composite/RulesT.hh
@@ -101,8 +101,8 @@ public:
 
   explicit Tvv3(M& _mesh) : Inherited(_mesh) { Base::set_subdiv_type(3); };
 
-  void raise(typename M::FaceHandle&   _fh, state_t _target_state);
-  void raise(typename M::VertexHandle& _vh, state_t _target_state);
+  void raise(typename M::FaceHandle&   _fh, state_t _target_state) override;
+  void raise(typename M::VertexHandle& _vh, state_t _target_state) override;
   MIPS_WARN_WA(Edge) // avoid warning
 };
 
@@ -126,9 +126,9 @@ public:
 
   explicit Tvv4(M& _mesh) : Inherited(_mesh) { Base::set_subdiv_type(4); };
 
-  void raise(typename M::FaceHandle&   _fh, state_t _target_state); 
-  void raise(typename M::VertexHandle& _vh, state_t _target_state);
-  void raise(typename M::EdgeHandle&   _eh, state_t _target_state);
+  void raise(typename M::FaceHandle&   _fh, state_t _target_state) override;
+  void raise(typename M::VertexHandle& _vh, state_t _target_state) override;
+  void raise(typename M::EdgeHandle&   _eh, state_t _target_state) override;
 
 private:
 
@@ -154,7 +154,7 @@ public:
 
   explicit VF(M& _mesh) : Inherited(_mesh) {}
 
-  void raise(typename M::FaceHandle& _fh, state_t _target_state);
+  void raise(typename M::FaceHandle& _fh, state_t _target_state) override;
   MIPS_WARN_WA(Edge)
   MIPS_WARN_WA(Vertex)
 };
@@ -176,7 +176,7 @@ public:
 
   explicit FF(M& _mesh) : Inherited(_mesh) {}
 
-  void raise(typename M::FaceHandle& _fh, state_t _target_state);
+  void raise(typename M::FaceHandle& _fh, state_t _target_state) override;
   MIPS_WARN_WA(Vertex) // avoid warning
   MIPS_WARN_WA(Edge  ) // avoid warning
 };
@@ -198,7 +198,7 @@ public:
 
   explicit FFc(M& _mesh) : Inherited(_mesh) {}
 
-  void raise(typename M::FaceHandle& _fh, state_t _target_state);
+  void raise(typename M::FaceHandle& _fh, state_t _target_state) override;
   MIPS_WARN_WA(Vertex) // avoid warning
   MIPS_WARN_WA(Edge  ) // avoid warning
 };
@@ -220,7 +220,7 @@ public:
 
   explicit FV(M& _mesh) : Inherited(_mesh) {}
 
-  void raise(typename M::VertexHandle& _vh, state_t _target_state);
+  void raise(typename M::VertexHandle& _vh, state_t _target_state) override;
   MIPS_WARN_WA(Face) // avoid warning
   MIPS_WARN_WA(Edge) // avoid warning
 };
@@ -279,7 +279,7 @@ public:
 
   explicit VV(M& _mesh) : Inherited(_mesh) {}
 
-  void raise(typename M::VertexHandle& _vh, state_t _target_state);
+  void raise(typename M::VertexHandle& _vh, state_t _target_state) override;
   MIPS_WARN_WA(Face) // avoid warning
   MIPS_WARN_WA(Edge) // avoid warning
 };
@@ -301,7 +301,7 @@ public:
 
   explicit VVc(M& _mesh) : Inherited(_mesh) {}
 
-  void raise(typename M::VertexHandle& _vh, state_t _target_state);
+  void raise(typename M::VertexHandle& _vh, state_t _target_state) override;
   MIPS_WARN_WA(Face) // avoid warning
   MIPS_WARN_WA(Edge) // avoid warning
 };
@@ -323,7 +323,7 @@ public:
 
   explicit VE(M& _mesh) : Inherited(_mesh) {}
 
-  void raise(typename M::EdgeHandle& _eh, state_t _target_state);
+  void raise(typename M::EdgeHandle& _eh, state_t _target_state) override;
   MIPS_WARN_WA(Face  ) // avoid warning
   MIPS_WARN_WA(Vertex) // avoid warning
 };
@@ -345,7 +345,7 @@ public:
 
   explicit VdE(M& _mesh) : Inherited(_mesh) {}
 
-  void raise(typename M::EdgeHandle& _eh, state_t _target_state);
+  void raise(typename M::EdgeHandle& _eh, state_t _target_state) override;
   MIPS_WARN_WA(Face  ) // avoid warning
   MIPS_WARN_WA(Vertex) // avoid warning
 };
@@ -367,7 +367,7 @@ public:
 
   explicit VdEc(M& _mesh) : Inherited(_mesh) {}
 
-  void raise(typename M::EdgeHandle& _eh, state_t _target_state);
+  void raise(typename M::EdgeHandle& _eh, state_t _target_state) override;
   MIPS_WARN_WA(Face  ) // avoid warning
   MIPS_WARN_WA(Vertex) // avoid warning
 };
@@ -389,7 +389,7 @@ public:
 
   explicit EV(M& _mesh) : Inherited(_mesh) {}
 
-  void raise(typename M::VertexHandle& _vh, state_t _target_state);
+  void raise(typename M::VertexHandle& _vh, state_t _target_state) override;
   MIPS_WARN_WA(Face) // avoid warning
   MIPS_WARN_WA(Edge) // avoid warning
 };
@@ -448,7 +448,7 @@ public:
 
   explicit EF(M& _mesh) : Inherited(_mesh) {}
 
-  void raise(typename M::FaceHandle& _fh, state_t _target_state);
+  void raise(typename M::FaceHandle& _fh, state_t _target_state) override;
   MIPS_WARN_WA(Edge  ) // avoid warning
   MIPS_WARN_WA(Vertex) // avoid warning
 };
@@ -470,7 +470,7 @@ public:
 
   explicit FE(M& _mesh) : Inherited(_mesh) {}
 
-  void raise(typename M::EdgeHandle& _eh, state_t _target_state);
+  void raise(typename M::EdgeHandle& _eh, state_t _target_state) override;
   MIPS_WARN_WA(Face  ) // avoid warning
   MIPS_WARN_WA(Vertex) // avoid warning
 };
@@ -492,7 +492,7 @@ public:
 
   explicit EdE(M& _mesh) : Inherited(_mesh) {}
 
-  void raise(typename M::EdgeHandle& _eh, state_t _target_state);
+  void raise(typename M::EdgeHandle& _eh, state_t _target_state) override;
   MIPS_WARN_WA(Face  ) // avoid warning
   MIPS_WARN_WA(Vertex) // avoid warning
 };
@@ -514,7 +514,7 @@ public:
 
   explicit EdEc(M& _mesh) : Inherited(_mesh) {}
 
-  void raise(typename M::EdgeHandle& _eh, state_t _target_state);
+  void raise(typename M::EdgeHandle& _eh, state_t _target_state) override;
   MIPS_WARN_WA(Face  ) // avoid warning
   MIPS_WARN_WA(Vertex) // avoid warning
 };
diff --git a/src/OpenMesh/Tools/Subdivider/Uniform/CatmullClarkT_impl.hh b/src/OpenMesh/Tools/Subdivider/Uniform/CatmullClarkT_impl.hh
index a117618f..40978930 100644
--- a/src/OpenMesh/Tools/Subdivider/Uniform/CatmullClarkT_impl.hh
+++ b/src/OpenMesh/Tools/Subdivider/Uniform/CatmullClarkT_impl.hh
@@ -333,7 +333,6 @@ CatmullClarkT<MeshType,RealType>::update_vertex( MeshType& _m, const VertexHandl
   // and http://www.cs.utah.edu/~lacewell/subdeval
   if ( _m.is_boundary( _vh))
   {
-    Normal   Vec;
     pos = _m.point(_vh);
     VertexEdgeIter   ve_itr;
     for ( ve_itr = _m.ve_iter( _vh); ve_itr.is_valid(); ++ve_itr)
diff --git a/src/OpenMesh/Tools/Subdivider/Uniform/Composite/CompositeT.hh b/src/OpenMesh/Tools/Subdivider/Uniform/Composite/CompositeT.hh
index 3227ded9..6a9b2fb0 100644
--- a/src/OpenMesh/Tools/Subdivider/Uniform/Composite/CompositeT.hh
+++ b/src/OpenMesh/Tools/Subdivider/Uniform/Composite/CompositeT.hh
@@ -96,8 +96,8 @@ public:
 
 public:
 
-  CompositeT(void) : parent_t(), p_mesh_(NULL) {}
-  explicit CompositeT(MeshType& _mesh) : parent_t(_mesh), p_mesh_(NULL) {};
+  CompositeT(void) : parent_t(), p_mesh_(nullptr) {}
+  explicit CompositeT(MeshType& _mesh) : parent_t(_mesh), p_mesh_(nullptr) {};
   virtual ~CompositeT() { }
 
 public: // inherited interface
@@ -122,13 +122,13 @@ protected: // inherited interface
   }
 
 #ifdef NDEBUG
-  bool cleanup( MeshType& ) 
+  bool cleanup( MeshType& ) override
 #else
   bool cleanup( MeshType& _m ) override
 #endif
   { 
     assert( p_mesh_ == &_m );
-    p_mesh_=NULL; 
+    p_mesh_=nullptr; 
     return true; 
   }
 
diff --git a/src/OpenMesh/Tools/Subdivider/Uniform/Sqrt3InterpolatingSubdividerLabsikGreinerT.hh b/src/OpenMesh/Tools/Subdivider/Uniform/Sqrt3InterpolatingSubdividerLabsikGreinerT.hh
index 6330797e..d3b7199c 100644
--- a/src/OpenMesh/Tools/Subdivider/Uniform/Sqrt3InterpolatingSubdividerLabsikGreinerT.hh
+++ b/src/OpenMesh/Tools/Subdivider/Uniform/Sqrt3InterpolatingSubdividerLabsikGreinerT.hh
@@ -409,7 +409,7 @@ private:
 
     typename MeshType::HalfedgeHandle heh;
     typename MeshType::VertexHandle   vh1, vh2, vh3, vh4, vhl, vhr;
-    typename MeshType::Point          zero(0,0,0), P1, P2, P3, P4;
+    typename MeshType::Point          P1, P2, P3, P4;
 
     /*
     //       *---------*---------*
diff --git a/src/OpenMesh/Tools/Subdivider/Uniform/SubdividerT.hh b/src/OpenMesh/Tools/Subdivider/Uniform/SubdividerT.hh
index a27c038f..d39070f8 100644
--- a/src/OpenMesh/Tools/Subdivider/Uniform/SubdividerT.hh
+++ b/src/OpenMesh/Tools/Subdivider/Uniform/SubdividerT.hh
@@ -102,7 +102,7 @@ public:
 
   /// Constructor to be used with interface 1 (calls attach())
   /// \see operator()( MeshType&, size_t )
-  explicit SubdividerT( MeshType &_m ) : attached_(NULL) {  attach(_m); }
+  explicit SubdividerT( MeshType &_m ) : attached_(nullptr) {  attach(_m); }
 
   //@}
 
@@ -157,7 +157,7 @@ public: /// \name Interface 2
     if ( attached_ )
     {
       cleanup( *attached_ );
-      attached_ = NULL;
+      attached_ = nullptr;
     }
   }
   //@}
diff --git a/src/OpenMesh/Tools/Utils/Gnuplot.cc b/src/OpenMesh/Tools/Utils/Gnuplot.cc
index a70ca1ad..88e91607 100644
--- a/src/OpenMesh/Tools/Utils/Gnuplot.cc
+++ b/src/OpenMesh/Tools/Utils/Gnuplot.cc
@@ -38,7 +38,7 @@
 #  define access _access
 #  define ACCESS_OK 0
 #  define PATH_SEP ";"
-#  define MKTEMP_AND_CHECK_FAILED(name) (_mktemp(name) == NULL)
+#  define MKTEMP_AND_CHECK_FAILED(name) (_mktemp(name) == nullptr)
 #else
 #  define ACCESS_OK X_OK
 #  define PATH_SEP ":"
@@ -368,7 +368,7 @@ void Gnuplot::plot_x(vector<double> d, const string &title)
   //
   //open temporary files for output
 #ifdef WIN32
-  if ( _mktemp(name) == NULL)
+  if ( _mktemp(name) == nullptr)
 #else
   if ( mkstemp(name) == -1 )
 #endif
diff --git a/src/OpenMesh/Tools/Utils/conio.cc b/src/OpenMesh/Tools/Utils/conio.cc
index 4d053893..9b0debf9 100644
--- a/src/OpenMesh/Tools/Utils/conio.cc
+++ b/src/OpenMesh/Tools/Utils/conio.cc
@@ -120,7 +120,7 @@ int kbhit(void)
     error += tcsetattr(0, TCSANOW, &Otty);
     tv.tv_sec = 0;
     tv.tv_usec = 100; /* insert at least a minimal delay */
-    select(1, NULL, NULL, NULL, &tv);
+    select(1, nullptr, nullptr, nullptr, &tv);
   }
   return (error == 0 ? cnt : -1 );
 }
diff --git a/src/OpenMesh/Tools/VDPM/VHierarchyWindow.cc b/src/OpenMesh/Tools/VDPM/VHierarchyWindow.cc
index 18d50558..4a97cda7 100644
--- a/src/OpenMesh/Tools/VDPM/VHierarchyWindow.cc
+++ b/src/OpenMesh/Tools/VDPM/VHierarchyWindow.cc
@@ -73,7 +73,7 @@ namespace VDPM {
 
 VHierarchyWindow::
 VHierarchyWindow() :
-  vhierarchy_(NULL), buffer_(NULL),buffer_min_ (0), buffer_max_(0), current_pos_(0) , window_min_(0), window_max_(0),  n_shift_(0)
+  vhierarchy_(nullptr), buffer_(nullptr),buffer_min_ (0), buffer_max_(0), current_pos_(0) , window_min_(0), window_max_(0),  n_shift_(0)
 {
 
 }
@@ -81,7 +81,7 @@ VHierarchyWindow() :
 
 VHierarchyWindow::
 VHierarchyWindow(VHierarchy &_vhierarchy) :
-  vhierarchy_(&_vhierarchy),buffer_(NULL),buffer_min_ (0), buffer_max_(0), current_pos_(0) , window_min_(0), window_max_(0) ,n_shift_(0)
+  vhierarchy_(&_vhierarchy),buffer_(nullptr),buffer_min_ (0), buffer_max_(0), current_pos_(0) , window_min_(0), window_max_(0) ,n_shift_(0)
 {
 }
 
@@ -89,7 +89,7 @@ VHierarchyWindow(VHierarchy &_vhierarchy) :
 VHierarchyWindow::
 ~VHierarchyWindow(void)
 {
-  if (buffer_ != NULL)
+  if (buffer_ != nullptr)
     free(buffer_);
 }
 
@@ -138,7 +138,7 @@ update_buffer(VHierarchyNodeHandle _node_handle)
 void
 VHierarchyWindow::init(VHierarchyNodeHandleContainer &_roots)
 {
-  if (buffer_ != NULL)
+  if (buffer_ != nullptr)
     free(buffer_);
 
   buffer_min_ = 0;