diff --git a/EInAPI.h b/EInAPI.h
index 6fa7498..40bc28d 100644
--- a/EInAPI.h
+++ b/EInAPI.h
@@ -486,6 +486,7 @@ EIN_EXPORT BOOL __stdcall EgtArcDeltaN( int nId, double* pdDeltaN) ;
 EIN_EXPORT BOOL __stdcall EgtArcNormVersor( int nId, int nRefId, double vtNorm[3]) ;
 EIN_EXPORT BOOL __stdcall EgtCurveCompoCenter( int nId, int nSimpCrv, int nRefId, double ptCen[3]) ;
 EIN_EXPORT BOOL __stdcall EgtSurfFrNormVersor( int nId, int nRefId, double vtNorm[3]) ;
+EIN_EXPORT BOOL __stdcall EgtSurfFrGrossArea( int nId, double* pdArea) ;
 EIN_EXPORT int  __stdcall EgtSurfFrChunkCount( int nId) ;
 EIN_EXPORT int  __stdcall EgtSurfFrChunkSimpleClassify( int nId1, int nChunk1, int nId2, int nChunk2) ;
 EIN_EXPORT int  __stdcall EgtSurfTmFacetCount( int nId) ;