diff --git a/SurfBezier.cpp b/SurfBezier.cpp
index 0b086e9..b481a79 100644
--- a/SurfBezier.cpp
+++ b/SurfBezier.cpp
@@ -869,6 +869,7 @@ SurfBezier::CopyFrom( const SurfBezier& sbSrc)
       m_pTrimReg = sbSrc.m_pTrimReg->Clone() ;
    }
    m_pSTM = sbSrc.GetAuxSurf()->Clone() ;
+   m_pSTMRefined = sbSrc.GetAuxSurfRefined()->Clone() ;
    for ( int i = 0 ; i < int( sbSrc.m_mCCEdge.size()) ; ++i) {
       m_mCCEdge.emplace_back() ;
       for ( int j = 0 ; j < int( sbSrc.m_mCCEdge[i].size()) ; ++j ) {