diff --git a/API_BeamMgr.cpp b/API_BeamMgr.cpp
index f18dc80..b511ba0 100644
--- a/API_BeamMgr.cpp
+++ b/API_BeamMgr.cpp
@@ -71,9 +71,9 @@ __stdcall EgtBeamSetPartCount( int nCount)
 
 //-----------------------------------------------------------------------------
 BOOL
-__stdcall EgtBeamSetPartBox( double dLength, double dHeight, double dWidth)
+__stdcall EgtBeamSetPartBox( double dLength, double dHeight, double dWidth, BOOL bUpdate)
 {
-   return ( ExeBeamSetPartBox( dLength, dHeight, dWidth) ? TRUE : FALSE) ;
+   return ( ExeBeamSetPartBox( dLength, dHeight, dWidth, ( bUpdate != FALSE)) ? TRUE : FALSE) ;
 }
 
 //-----------------------------------------------------------------------------