diff --git a/EGkVolZmap.h b/EGkVolZmap.h
index f56f96a..8013af5 100644
--- a/EGkVolZmap.h
+++ b/EGkVolZmap.h
@@ -32,7 +32,7 @@ class __declspec( novtable) IVolZmap : public IGeoObj
       virtual bool Create( const Point3d& ptO, double dDimX, double dDimY, double dDimZ, double dStep, bool bTriDex, int* nError = nullptr) = 0 ;
       virtual bool CreateEmpty( const Point3d& ptO, double dDimX, double dDimY, double dDimZ, double dStep, bool bTriDex, int* nError = nullptr) = 0 ;
       virtual bool CreateFromFlatRegion( const ISurfFlatRegion& Surf, double dDimZ, double dStep, bool bTriDex, int* nError = nullptr) = 0 ;
-      virtual bool CreateFromTriMesh( const ISurfTriMesh& Surf, double dStep, bool bTriDex, double dExtraBox = 0, int* nError = nullptr) = 0 ;
+      virtual bool CreateFromTriMesh( const ISurfTriMesh& Surf, double dStep, bool bTriDex, double dExtraBox = 0, int* nError = nullptr, bool bForceClosed = false) = 0 ;
       virtual int  GetBlockCount( void) const = 0 ;
       virtual int  GetBlockUpdatingCounter( int nBlock) const = 0 ;
       virtual bool GetBlockTriangles( int nBlock, TRIA3DEXVECTOR& vTria) const = 0 ;
diff --git a/EXeExecutor.h b/EXeExecutor.h
index 9f7a603..4b028ed 100644
--- a/EXeExecutor.h
+++ b/EXeExecutor.h
@@ -441,7 +441,7 @@ EXE_EXPORT int  ExeCreateVolZmap( int nParentId, const Point3d& ptIni, double dD
 EXE_EXPORT int  ExeCreateVolZmapEmpty( int nParentId, const Point3d& ptIni, double dDimX,
                                        double dDimY, double dDimZ, double dPrec, bool bTriDex, int nRefType) ;
 EXE_EXPORT int  ExeCreateVolZmapByRegionExtrusion( int nParentId, int nSfrId, double dDimZ, double dPrec, bool bTriDex) ;
-EXE_EXPORT int  ExeCreateVolZmapFromSurfTm( int nParentId, int nStmId, double dPrec, bool bTriDex, double dExtraBox = 0) ;
+EXE_EXPORT int  ExeCreateVolZmapFromSurfTm( int nParentId, int nStmId, double dPrec, bool bTriDex, double dExtraBox = 0, bool bForceClosed = false) ;
 
 // GeomDB PartLayer
 EXE_EXPORT bool ExeIsPart( int nPartId) ;