diff --git a/EGkVector3d.h b/EGkVector3d.h
index 4dff636..048c264 100644
--- a/EGkVector3d.h
+++ b/EGkVector3d.h
@@ -274,7 +274,7 @@ CrossXY( const Vector3d& vtV1, const Vector3d& vtV2)
 //! Somma mediata di due vettori (baricentrica)
 //----------------------------------------------------------------------------
 inline Vector3d 
-Media( const Vector3d& vtV1, const Vector3d& vtV2, double dCoeff)
+Media( const Vector3d& vtV1, const Vector3d& vtV2, double dCoeff = 0.5)
 {
    return ( Vector3d( ( 1 - dCoeff) * vtV1.x + dCoeff * vtV2.x,
                       ( 1 - dCoeff) * vtV1.y + dCoeff * vtV2.y,