diff --git a/MachMgrRawParts.cpp b/MachMgrRawParts.cpp
index 6a8cc7c..3ca21b0 100644
--- a/MachMgrRawParts.cpp
+++ b/MachMgrRawParts.cpp
@@ -414,7 +414,7 @@ MachMgr::AddRawPart( int nSurfId, Color cCol)
      // ne calcolo la silhouette secondo Z+
       POLYLINEVECTOR vPL ;
       bool bSilh = false ;
-      if ( pStm->GetSilhouette( Z_AX, vPL)  &&  vPL.size() > 0) {
+      if ( pStm->GetSilhouette( Z_AX, 10.0, vPL)  &&  vPL.size() > 0) {
         // cerco il contorno esterno
          int nInd = - 1 ;
          double dMaxArea = 0 ;