diff --git a/EgtGeomKernel.rc b/EgtGeomKernel.rc
index 55474c7..5f56abf 100644
Binary files a/EgtGeomKernel.rc and b/EgtGeomKernel.rc differ
diff --git a/Simple CDSurfFrMove.cpp b/Simple CDSurfFrMove.cpp
index b4d9dcc..02feff7 100644
--- a/Simple CDSurfFrMove.cpp	
+++ b/Simple CDSurfFrMove.cpp	
@@ -586,88 +586,95 @@ MySimpleCDSurfFrMove::RotateLineNoCollisionLine( const CurveLine* pLine1, const
 
   // calcolo la minima rotazione degli estremi interni all'intervallo comune
    double dNewAng = dAng ;
-   if ( dRadS1 >= dRadS2) {
-      vtDirS1 /= dRadS1 ;
-      CurveArc ArcS1 ;
-      ArcS1.Set( ptCen, Z_AX, dRadS1, vtDirS1, dAng, 0) ;
-      IntersLineArc intLA( *pLine2, ArcS1) ;
-      if ( intLA.GetNumInters() == 2) {
-         IntCrvCrvInfo iccInfo1, iccInfo2 ;
-         intLA.GetIntCrvCrvInfo( 0, iccInfo1) ;
-         intLA.GetIntCrvCrvInfo( 1, iccInfo2) ;
-         dNewAng = dAng * min( iccInfo1.IciB[0].dU, iccInfo2.IciB[0].dU) ;
+   if ( ! AreSamePointXYEpsilon( ptS1, ptS2, 10 * EPS_SMALL)) {
+      if ( dRadS1 >= dRadS2) {
+         vtDirS1 /= dRadS1 ;
+         CurveArc ArcS1 ;
+         ArcS1.Set( ptCen, Z_AX, dRadS1, vtDirS1, dAng, 0) ;
+         IntersLineArc intLA( *pLine2, ArcS1) ;
+         if ( intLA.GetNumInters() == 2) {
+            IntCrvCrvInfo iccInfo1, iccInfo2 ;
+            intLA.GetIntCrvCrvInfo( 0, iccInfo1) ;
+            intLA.GetIntCrvCrvInfo( 1, iccInfo2) ;
+            dNewAng = dAng * min( iccInfo1.IciB[0].dU, iccInfo2.IciB[0].dU) ;
+         }
+         else if ( intLA.GetNumInters() == 1) {
+            IntCrvCrvInfo iccInfo ;
+            intLA.GetIntCrvCrvInfo( 0, iccInfo) ;
+            dNewAng = dAng * iccInfo.IciB[0].dU ;
+         }
       }
-      else if ( intLA.GetNumInters() == 1) {
-         IntCrvCrvInfo iccInfo ;
-         intLA.GetIntCrvCrvInfo( 0, iccInfo) ;
-         dNewAng = dAng * iccInfo.IciB[0].dU ;
+      else {
+         vtDirS2 /= dRadS2 ;
+         CurveArc ArcS2 ;
+         ArcS2.Set( ptCen, Z_AX, dRadS2, vtDirS2, - dAng, 0) ;
+         IntersLineArc intLA( *pLine1, ArcS2) ;
+         if ( intLA.GetNumInters() == 2) {
+            IntCrvCrvInfo iccInfo1, iccInfo2 ;
+            intLA.GetIntCrvCrvInfo( 0, iccInfo1) ;
+            intLA.GetIntCrvCrvInfo( 1, iccInfo2) ;
+            dNewAng = dAng * min( iccInfo1.IciB[0].dU, iccInfo2.IciB[0].dU) ;
+         }
+         else if ( intLA.GetNumInters() == 1) {
+            IntCrvCrvInfo iccInfo ;
+            intLA.GetIntCrvCrvInfo( 0, iccInfo) ;
+            dNewAng = dAng * iccInfo.IciB[0].dU ;
+         }
       }
    }
-   else {
-      vtDirS2 /= dRadS2 ;
-      CurveArc ArcS2 ;
-      ArcS2.Set( ptCen, Z_AX, dRadS2, vtDirS2, - dAng, 0) ;
-      IntersLineArc intLA( *pLine1, ArcS2) ;
-      if ( intLA.GetNumInters() == 2) {
-         IntCrvCrvInfo iccInfo1, iccInfo2 ;
-         intLA.GetIntCrvCrvInfo( 0, iccInfo1) ;
-         intLA.GetIntCrvCrvInfo( 1, iccInfo2) ;
-         dNewAng = dAng * min( iccInfo1.IciB[0].dU, iccInfo2.IciB[0].dU) ;
+   if ( ! AreSamePointXYEpsilon( ptE1, ptE2, 10 * EPS_SMALL)) {
+      if ( dRadE1 <= dRadE2) {
+         vtDirE1 /= dRadE1 ;
+         CurveArc ArcE1 ;
+         ArcE1.Set( ptCen, Z_AX, dRadE1, vtDirE1, dAng, 0) ;
+         IntersLineArc intLA( *pLine2, ArcE1) ;
+         if ( intLA.GetNumInters() == 2) {
+            IntCrvCrvInfo iccInfo1, iccInfo2 ;
+            intLA.GetIntCrvCrvInfo( 0, iccInfo1) ;
+            intLA.GetIntCrvCrvInfo( 1, iccInfo2) ;
+            if ( bCCW)
+               dNewAng = min( dNewAng, dAng * min( iccInfo1.IciB[0].dU, iccInfo2.IciB[0].dU)) ;
+            else
+               dNewAng = max( dNewAng, dAng * min( iccInfo1.IciB[0].dU, iccInfo2.IciB[0].dU)) ;
+         }
+         else if ( intLA.GetNumInters() == 1) {
+            IntCrvCrvInfo iccInfo ;
+            intLA.GetIntCrvCrvInfo( 0, iccInfo) ;
+            if ( bCCW)
+               dNewAng = min( dNewAng, dAng * iccInfo.IciB[0].dU) ;
+            else
+               dNewAng = max( dNewAng, dAng * iccInfo.IciB[0].dU) ;
+         }
       }
-      else if ( intLA.GetNumInters() == 1) {
-         IntCrvCrvInfo iccInfo ;
-         intLA.GetIntCrvCrvInfo( 0, iccInfo) ;
-         dNewAng = dAng * iccInfo.IciB[0].dU ;
-      }
-   }
-   if ( dRadE1 <= dRadE2) {
-      vtDirE1 /= dRadE1 ;
-      CurveArc ArcE1 ;
-      ArcE1.Set( ptCen, Z_AX, dRadE1, vtDirE1, dAng, 0) ;
-      IntersLineArc intLA( *pLine2, ArcE1) ;
-      if ( intLA.GetNumInters() == 2) {
-         IntCrvCrvInfo iccInfo1, iccInfo2 ;
-         intLA.GetIntCrvCrvInfo( 0, iccInfo1) ;
-         intLA.GetIntCrvCrvInfo( 1, iccInfo2) ;
-         if ( bCCW)
-            dNewAng = min( dNewAng, dAng * min( iccInfo1.IciB[0].dU, iccInfo2.IciB[0].dU)) ;
-         else
-            dNewAng = max( dNewAng, dAng * min( iccInfo1.IciB[0].dU, iccInfo2.IciB[0].dU)) ;
-      }
-      else if ( intLA.GetNumInters() == 1) {
-         IntCrvCrvInfo iccInfo ;
-         intLA.GetIntCrvCrvInfo( 0, iccInfo) ;
-         if ( bCCW)
-            dNewAng = min( dNewAng, dAng * iccInfo.IciB[0].dU) ;
-         else
-            dNewAng = max( dNewAng, dAng * iccInfo.IciB[0].dU) ;
-      }
-   }
-   else {
-      vtDirE2 /= dRadE2 ;
-      CurveArc ArcE2 ;
-      ArcE2.Set( ptCen, Z_AX, dRadE2, vtDirE2, - dAng, 0) ;
-      IntersLineArc intLA( *pLine1, ArcE2) ;
-      if ( intLA.GetNumInters() == 2) {
-         IntCrvCrvInfo iccInfo1, iccInfo2 ;
-         intLA.GetIntCrvCrvInfo( 0, iccInfo1) ;
-         intLA.GetIntCrvCrvInfo( 1, iccInfo2) ;
-         if ( bCCW)
-            dNewAng = min( dNewAng, dAng * min( iccInfo1.IciB[0].dU, iccInfo2.IciB[0].dU)) ;
-         else
-            dNewAng = max( dNewAng, dAng * min( iccInfo1.IciB[0].dU, iccInfo2.IciB[0].dU)) ;
-      }
-      else if ( intLA.GetNumInters() == 1) {
-         IntCrvCrvInfo iccInfo ;
-         intLA.GetIntCrvCrvInfo( 0, iccInfo) ;
-         if ( bCCW)
-            dNewAng = min( dNewAng, dAng * iccInfo.IciB[0].dU) ;
-         else
-            dNewAng = max( dNewAng, dAng * iccInfo.IciB[0].dU) ;
+      else {
+         vtDirE2 /= dRadE2 ;
+         CurveArc ArcE2 ;
+         ArcE2.Set( ptCen, Z_AX, dRadE2, vtDirE2, - dAng, 0) ;
+         IntersLineArc intLA( *pLine1, ArcE2) ;
+         if ( intLA.GetNumInters() == 2) {
+            IntCrvCrvInfo iccInfo1, iccInfo2 ;
+            intLA.GetIntCrvCrvInfo( 0, iccInfo1) ;
+            intLA.GetIntCrvCrvInfo( 1, iccInfo2) ;
+            if ( bCCW)
+               dNewAng = min( dNewAng, dAng * min( iccInfo1.IciB[0].dU, iccInfo2.IciB[0].dU)) ;
+            else
+               dNewAng = max( dNewAng, dAng * min( iccInfo1.IciB[0].dU, iccInfo2.IciB[0].dU)) ;
+         }
+         else if ( intLA.GetNumInters() == 1) {
+            IntCrvCrvInfo iccInfo ;
+            intLA.GetIntCrvCrvInfo( 0, iccInfo) ;
+            if ( bCCW)
+               dNewAng = min( dNewAng, dAng * iccInfo.IciB[0].dU) ;
+            else
+               dNewAng = max( dNewAng, dAng * iccInfo.IciB[0].dU) ;
+         }
       }
    }
+   if ( AreSamePointXYEpsilon( ptS1, ptS2, 10 * EPS_SMALL)  &&  
+        AreSamePointXYEpsilon( ptE1, ptE2, 10 * EPS_SMALL))
+      dNewAng = 0 ;
   // confronto con rotazione corrente
-   if ( abs( dNewAng) < EPS_SMALL)
+   if ( abs( dNewAng) < EPS_ANG_SMALL)
       dAng = 0 ;
    else if ( bCCW  &&  dNewAng > 0)
       dAng = min( dAng, dNewAng) ;