diff --git a/API_GeoSnap.cpp b/API_GeoSnap.cpp
index 4aa6ffa..c39772e 100644
--- a/API_GeoSnap.cpp
+++ b/API_GeoSnap.cpp
@@ -395,6 +395,16 @@ __stdcall EgtSurfFrNormVersor( int nId, int nRefId, double vtNorm[3])
    return TRUE ;
 }
 
+//----------------------------------------------------------------------------
+BOOL
+__stdcall EgtSurfFrGrossArea( int nId, double* pdArea)
+{
+   if ( pdArea == nullptr)
+      return FALSE ;
+  // recupero l'area approssimata
+   return ( ExeSurfFrGrossArea( nId, *pdArea) ? TRUE : FALSE) ;
+}
+
 //----------------------------------------------------------------------------
 int
 __stdcall EgtSurfFrChunkCount( int nId)
diff --git a/EgtInterface.rc b/EgtInterface.rc
index 6b32ba6..b1f1126 100644
Binary files a/EgtInterface.rc and b/EgtInterface.rc differ