diff --git a/EGkVolZmap.h b/EGkVolZmap.h
index 6e75c03..433b706 100644
--- a/EGkVolZmap.h
+++ b/EGkVolZmap.h
@@ -55,6 +55,7 @@ class __declspec( novtable) IVolZmap : public IGeoObj
       virtual bool Create( const Point3d& ptO, double dDimX, double dDimY, double dDimZ, double dPrec, bool bTriDex) = 0 ;
       virtual bool CreateFromFlatRegion( const ISurfFlatRegion& Surf, double dDimZ, double dPrec, bool bTriDex) = 0 ;
       virtual bool CreateFromTriMesh( const ISurfTriMesh& Surf, double dPrec, bool bTriDex) = 0 ;
+      virtual bool CreateEmptyMap( const Point3d& ptO, double dLengthX, double dLengthY, double dLengthZ, double dStep, bool bTriDex) = 0 ;
       virtual int  GetBlockCount( void) const = 0 ;
       virtual int  GetBlockUpdatingCounter( int nBlock) const = 0 ;
       virtual bool GetBlockTriangles( int nBlock, TRIA3DEXVECTOR& vTria) const = 0 ;