diff --git a/EInAPI.h b/EInAPI.h
index a936e4b..8ee82c2 100644
--- a/EInAPI.h
+++ b/EInAPI.h
@@ -945,6 +945,7 @@ EIN_EXPORT BOOL __stdcall EgtSetMachiningGeometry( int nNumId, const int nIds[],
 EIN_EXPORT BOOL __stdcall EgtPreviewMachining( BOOL bRecalc) ;
 EIN_EXPORT BOOL __stdcall EgtApplyMachining( BOOL bRecalc) ;
 EIN_EXPORT BOOL __stdcall EgtUpdateMachining( void) ;
+EIN_EXPORT BOOL __stdcall EgtChangePreviewMachiningToolShow( int nLookFlag) ;
 EIN_EXPORT BOOL __stdcall EgtPreparePreviewMachiningTool( void) ;
 EIN_EXPORT BOOL __stdcall EgtRemovePreviewMachiningTool( void) ;
 EIN_EXPORT int  __stdcall EgtGetPreviewMachiningToolStepCount( void) ;
diff --git a/EMkMachMgr.h b/EMkMachMgr.h
index de942f6..709b98f 100644
--- a/EMkMachMgr.h
+++ b/EMkMachMgr.h
@@ -266,6 +266,7 @@ class __declspec( novtable) IMachMgr
       virtual bool RemoveMachiningPreview( void) = 0 ;
       virtual bool MachiningApply( bool bRecalc, bool bPostApply = true) = 0 ;
       virtual bool MachiningUpdate( bool bPostApply = true) = 0 ;
+      virtual bool ChangePreviewMachiningToolShow( int nLookFlag) = 0 ;
       virtual bool PreparePreviewMachiningTool( void) const = 0 ;
       virtual bool RemovePreviewMachiningTool( void) const = 0 ;
       virtual int  GetPreviewMachiningToolStepCount( void) const = 0 ; 
diff --git a/EXeExecutor.h b/EXeExecutor.h
index ae31689..d38ec4c 100644
--- a/EXeExecutor.h
+++ b/EXeExecutor.h
@@ -1270,6 +1270,7 @@ EXE_EXPORT bool ExeSetMachiningGeometry( const SELVECTOR& vIds) ;
 EXE_EXPORT bool ExePreviewMachining( bool bRecalc) ;
 EXE_EXPORT bool ExeApplyMachining( bool bRecalc, bool bPostApply = true) ;
 EXE_EXPORT bool ExeUpdateMachining( bool bPostApply = true) ;
+EXE_EXPORT bool ExeChangePreviewMachiningToolShow( int nLookFlag) ;
 EXE_EXPORT bool ExePreparePreviewMachiningTool( void) ;
 EXE_EXPORT bool ExeRemovePreviewMachiningTool( void) ;
 EXE_EXPORT int  ExeGetPreviewMachiningToolStepCount( void) ;