diff --git a/SurfBezier.h b/SurfBezier.h
index 71c3d53..2e50e24 100644
--- a/SurfBezier.h
+++ b/SurfBezier.h
@@ -75,7 +75,11 @@ class SurfBezier : public ISurfBezier, public IGeoObjRW
       bool GetVolume( double& dVolume) const override
                { if ( &dVolume == nullptr)
                     return false ;
+                 if( m_pSTM == nullptr)
+                    GetAuxSurf() ;
                  dVolume = 0 ;
+                 if( m_pSTM != nullptr)
+                    m_pSTM->GetVolume( dVolume) ;
                  return true ; }
       bool GetCentroid( Point3d& ptCen) const override ;
       bool Invert( void) override ;
diff --git a/SurfTriMesh.cpp b/SurfTriMesh.cpp
index 8a64e24..8124565 100644
--- a/SurfTriMesh.cpp
+++ b/SurfTriMesh.cpp
@@ -2835,12 +2835,10 @@ SurfTriMesh::CreateByScrewing( const PolyLine& PL, const Point3d& ptAx, const Ve
 
   // verifico che la polilinea non attraversi l'asse di rivoluzione o lo tocchi in punti interni
    PolyLine MyPL = PL ;
-   // commented for debug
    if ( ! VeryfyPolylineForRevolution( MyPL, ptAx, vtAx)  &&  ! AdjustPolylineForRevolution( MyPL, ptAx, vtAx)) {
       LOG_ERROR( GetEGkLogger(), "StmCreateByRevolution : polyline inside meets axis")
       return false ;
    }
-   // commented for debug
 
   // imposto ricalcolo
    m_nStatus = ERR ;