diff --git a/EGkSurfTriMesh.h b/EGkSurfTriMesh.h
index 6b9c714..978ca1e 100644
--- a/EGkSurfTriMesh.h
+++ b/EGkSurfTriMesh.h
@@ -128,6 +128,8 @@ class __declspec( novtable) ISurfTriMesh : public ISurf
       virtual bool GetShellArea( int nShell, double& dArea) const = 0 ;
       virtual bool RemoveShell( int nShell) = 0 ;
       virtual ISurfTriMesh* CloneShell( int nShell) const = 0 ;
+      virtual bool GetPartLocalBBox( int nP, BBox3d& b3Loc) const = 0 ;
+      virtual bool GetPartBBox( int nP, const Frame3d& frRef, BBox3d& b3Ref) const = 0 ;
       virtual int  GetPartCount( void) const = 0 ;
       virtual bool GetPartArea( int nPart, double& dArea) const = 0 ;
       virtual bool GetPartVolume( int nPart, double& dVolume) const = 0 ;