diff --git a/graf3d/gl/inc/TGLCamera.h b/graf3d/gl/inc/TGLCamera.h
index 2f0fb6fd3ff9e296f0c765a1bc77c79d1f93f684..3aa61f17bb37697ff6fed303efc244874991f09b 100644
--- a/graf3d/gl/inc/TGLCamera.h
+++ b/graf3d/gl/inc/TGLCamera.h
@@ -174,6 +174,9 @@ public:
    TGLCamera(const TGLVector3 & hAxis, const TGLVector3 & vAxis);
    virtual ~TGLCamera();
 
+   virtual Bool_t IsOrthographic() const { return kFALSE; }
+   virtual Bool_t IsPersepective() const { return kFALSE; }
+
    const TGLMatrix& RefModelViewMatrix() const { return fModVM; }
 
    Bool_t IsCacheDirty() const { return fCacheDirty; }