diff --git a/CAvSilhouetteSurfTm.cpp b/CAvSilhouetteSurfTm.cpp
index 31bce75..798f488 100644
--- a/CAvSilhouetteSurfTm.cpp
+++ b/CAvSilhouetteSurfTm.cpp
@@ -1218,19 +1218,19 @@ CAvParSilhouettesSurfTm::PrepareForRegion( void)
    if ( m_dSideAng < EPS_ANG_SMALL)
       m_cavTstm.SetStdTool( m_dDimZ + m_dOffsR, m_dRad + m_dOffsR, m_dCornRad + m_dOffsR) ;
    else {
-      double dDelta ;
+      double dDeltaRad ;
       double dSideAngRad = m_dSideAng * DEGTORAD ;
       if ( m_dSideAng > 0) {
          if ( m_dCornRad < EPS_SMALL)
-            dDelta = 2 * m_dMaxMat * tan( dSideAngRad) ;
+            dDeltaRad = m_dMaxMat * tan( dSideAngRad) ;
          else
-            dDelta = 2 * ( m_dCornRad * cos( dSideAngRad) +
-                         ( m_dMaxMat + m_dCornRad * ( sin( dSideAngRad) - 1)) * tan( dSideAngRad)) ;
+            dDeltaRad = ( m_dCornRad * cos( dSideAngRad) +
+                        ( m_dMaxMat + m_dCornRad * ( sin( dSideAngRad) - 1)) * tan( dSideAngRad)) ;
       }
       else
-         dDelta = 2 * tan( dSideAngRad) * m_dMaxMat ;
+         dDeltaRad = tan( dSideAngRad) * m_dMaxMat ;
 
-      double dStemRad = m_dRad + dDelta ;
+      double dStemRad = m_dRad + dDeltaRad ;
       double dTipRad = m_dRad ;
       m_cavTstm.SetAdvTool( m_dDimZ + m_dOffsR, dStemRad + m_dOffsR, m_dMaxMat, dTipRad + m_dOffsR, m_dCornRad + m_dOffsR) ;
    }