diff --git a/EgtGeomKernel.rc b/EgtGeomKernel.rc
index 05c555e..97503c8 100644
Binary files a/EgtGeomKernel.rc and b/EgtGeomKernel.rc differ
diff --git a/EgtGeomKernel.vcxproj b/EgtGeomKernel.vcxproj
index 739262b..1ea9170 100644
--- a/EgtGeomKernel.vcxproj
+++ b/EgtGeomKernel.vcxproj
@@ -116,7 +116,7 @@
       <MultiProcessorCompilation>true</MultiProcessorCompilation>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <EnablePREfast>false</EnablePREfast>
-      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard>stdcpp20</LanguageStandard>
     </ClCompile>
     <Link>
       <SubSystem>Windows</SubSystem>
@@ -151,7 +151,7 @@ copy $(TargetPath) \EgtProg\DllD32</Command>
       <MinimalRebuild>false</MinimalRebuild>
       <MultiProcessorCompilation>true</MultiProcessorCompilation>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
-      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard>stdcpp20</LanguageStandard>
       <AdditionalOptions>-Wno-tautological-undefined-compare</AdditionalOptions>
     </ClCompile>
     <Link>
@@ -199,7 +199,7 @@ copy $(TargetPath) \EgtProg\DllD64</Command>
       <EnableParallelCodeGeneration>true</EnableParallelCodeGeneration>
       <WholeProgramOptimization>false</WholeProgramOptimization>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
-      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard>stdcpp20</LanguageStandard>
     </ClCompile>
     <Link>
       <SubSystem>Windows</SubSystem>
@@ -245,7 +245,7 @@ copy $(TargetPath) \EgtProg\Dll32</Command>
       <EnableFiberSafeOptimizations>false</EnableFiberSafeOptimizations>
       <WholeProgramOptimization>false</WholeProgramOptimization>
       <DebugInformationFormat>None</DebugInformationFormat>
-      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard>stdcpp20</LanguageStandard>
       <AdditionalOptions>-Wno-tautological-undefined-compare</AdditionalOptions>
       <IntelJCCErratum>true</IntelJCCErratum>
     </ClCompile>
diff --git a/ExtDimension.cpp b/ExtDimension.cpp
index dd664ee..c5a337d 100644
--- a/ExtDimension.cpp
+++ b/ExtDimension.cpp
@@ -1087,7 +1087,7 @@ ExtDimension::Update( void) const
          if ( m_nType == DT_RADIAL)
             sVal = "R " + sVal ;
          else if ( m_nType == DT_DIAMETRAL)
-            sVal = u8"\u00D8 " + sVal ;
+            sVal = reinterpret_cast<const char *>( u8"\u00D8") + sVal ;
          ReplaceString( m_sCalcText, IS_MEASURE, sVal) ;
       }
      // punto di inserimento del testo
diff --git a/GeoObjFactory.h b/GeoObjFactory.h
index 841bb62..f545d3c 100644
--- a/GeoObjFactory.h
+++ b/GeoObjFactory.h
@@ -28,41 +28,6 @@
 #define GEOOBJ_NGEIDTOTYPE( nNgeId)       GeoObjFactory::NgeIdToType( nNgeId)
 #define GEOOBJ_CREATE( nKey)              GeoObjFactory::Create( nKey)
 
-//----------------------------------------------------------------------------
-template <class T> 
-class GeoObjRegister
-{
-   public :
-      static bool DoRegister( int nKey, int nNgeId)
-         {  if ( ! GeoObjFactory::Register( nKey, NgeAscKeyW[nNgeId], nNgeId, Create))
-               return false ;
-            GetTypePrivate() = nKey ;
-            GetKeyPrivate() = NgeAscKeyW[nNgeId] ;
-            GetNgeIdPrivate() = nNgeId ;
-            return true ; }
-      static IGeoObj* Create( void) 
-         {  return new( std::nothrow) T ; }
-      static int GetType( void) 
-         { return GetTypePrivate() ; }
-      static const std::string& GetKey( void) 
-         { return GetKeyPrivate() ; }
-      static int GetNgeId( void) 
-         { return GetNgeIdPrivate() ; }
-
-   private :
-      GeoObjRegister( void)  {}
-      ~GeoObjRegister( void) {}
-      static int& GetTypePrivate( void) 
-         { static int  s_nType ;
-           return s_nType ; }
-      static std::string& GetKeyPrivate( void) 
-         { static std::string  s_sKey ;
-           return s_sKey ; }
-      static int& GetNgeIdPrivate( void) 
-         { static int  s_nNgeId ;
-           return s_nNgeId ; }
-} ;
-
 //----------------------------------------------------------------------------
 class GeoObjFactory
 {
@@ -117,3 +82,38 @@ class GeoObjFactory
          {  static CreatorMap s_CreatorMap ;
             return s_CreatorMap ; }
 } ;
+
+//----------------------------------------------------------------------------
+template <class T> 
+class GeoObjRegister
+{
+   public :
+      static bool DoRegister( int nKey, int nNgeId)
+         {  if ( ! GeoObjFactory::Register( nKey, NgeAscKeyW[nNgeId], nNgeId, Create))
+               return false ;
+            GetTypePrivate() = nKey ;
+            GetKeyPrivate() = NgeAscKeyW[nNgeId] ;
+            GetNgeIdPrivate() = nNgeId ;
+            return true ; }
+      static IGeoObj* Create( void) 
+         {  return new( std::nothrow) T ; }
+      static int GetType( void) 
+         { return GetTypePrivate() ; }
+      static const std::string& GetKey( void) 
+         { return GetKeyPrivate() ; }
+      static int GetNgeId( void) 
+         { return GetNgeIdPrivate() ; }
+
+   private :
+      GeoObjRegister( void)  {}
+      ~GeoObjRegister( void) {}
+      static int& GetTypePrivate( void) 
+         { static int  s_nType ;
+           return s_nType ; }
+      static std::string& GetKeyPrivate( void) 
+         { static std::string  s_sKey ;
+           return s_sKey ; }
+      static int& GetNgeIdPrivate( void) 
+         { static int  s_nNgeId ;
+           return s_nNgeId ; }
+} ;
diff --git a/Voronoi.cpp b/Voronoi.cpp
index 0146793..bc92e76 100644
--- a/Voronoi.cpp
+++ b/Voronoi.cpp
@@ -21,6 +21,7 @@
 #include "Voronoi.h"
 #include "/EgtDev/Include/EGkDistPointCurve.h"
 #include "/EgtDev/Include/EGkChainCurves.h"
+#include "/EgtDev/Extern/vroni/Include/vroni_object.h"
 
 using namespace std ;
 
diff --git a/Voronoi.h b/Voronoi.h
index d0f033b..e39ad3a 100644
--- a/Voronoi.h
+++ b/Voronoi.h
@@ -19,7 +19,6 @@
 #include "/EgtDev/Include/EGkCurveBezier.h"
 #include "/EgtDev/Include/EGkCurveComposite.h"
 #include "/EgtDev/Include/EGkCurveLine.h"
-#include "/EgtDev/Extern/vroni/Include/vroni_object.h"
 
 //----------------------------------------------------------------------------
 static const bool USE_VORONOI = true ;
@@ -30,6 +29,7 @@ static const double VRONI_JUNCTION_CLOSED = 2.0 ;
 
 //-------------------------- Forward Definitions -------------------------------
 class ISurfFlatRegion ;
+class vroniObject ;
 
 //----------------------------------------------------------------------------
 class Voronoi