diff --git a/Designing/WinLib/WinCalculate.lua b/Designing/WinLib/WinCalculate.lua
index 5e4611a..a5693e8 100644
--- a/Designing/WinLib/WinCalculate.lua
+++ b/Designing/WinLib/WinCalculate.lua
@@ -58,50 +58,52 @@ end
 ---------------------------------------------------------------------
 -- funzione che trova punto di intersezione fra due curve eventualmente estendendole
 local function FindIntersectionPoint( nCrv1, nCrv2, ptRef)
-   local ptInt = EgtIP( nCrv1, nCrv2, ptRef)
-   if not ptInt then
-      -- se entrambe linee
-      if EgtGetType( nCrv1) == GDB_TY.CRV_LINE and EgtGetType( nCrv2) == GDB_TY.CRV_LINE then
+   local ptInt
+   -- se archi, cerco intersezioni tra le circonferenze
+   if EgtGetType( nCrv1) == GDB_TY.CRV_ARC and EgtGetType( nCrv2) == GDB_TY.CRV_ARC then
+      -- trovo intersezione tra le due circonferenze
+      local nCircle1 = EgtCircle( GDB_ID.ROOT, EgtCP( nCrv1), EgtArcRadius( nCrv1))
+      local nCircle2 = EgtCircle( GDB_ID.ROOT, EgtCP( nCrv2), EgtArcRadius( nCrv2))
+      ptInt = EgtIP( nCircle1, nCircle2, ptRef)
+      EgtModifyCurveStartPoint( nCrv1, ptInt)
+      EgtModifyCurveEndPoint( nCrv2, ptInt)
+      EgtErase( nCircle1)
+      EgtErase( nCircle2)
+      
+   elseif EgtGetType( nCrv1) == GDB_TY.CRV_ARC or EgtGetType( nCrv2) == GDB_TY.CRV_ARC then
+      local nLine = EgtIf( EgtGetType( nCrv1) == GDB_TY.CRV_LINE, nCrv1, nCrv2)
+      local nArc = EgtIf( nLine == nCrv1, nCrv2, nCrv1)
+      -- creo circonferenza corrispondente all'arco
+      local nCircle = EgtCircle( GDB_ID.ROOT, EgtCP( nArc), EgtArcRadius( nArc))
+      -- prolungo la linea dal lato opportuno
+      local dDist1 = dist( EgtSP( nLine), ptRef)
+      local dDist2 = dist( EgtEP( nLine), ptRef)
+      if dDist1 < dDist2 then
+         EgtExtendCurveStartByLen( nLine, 10000)
+      else
+         EgtExtendCurveEndByLen( nLine, 10000)
+      end
+      -- ricavo il punto di riferimento dalla circonferenza
+      local ptNewRef = EgtIf( nArc == nCrv2, EgtEP( nArc), EgtSP( nArc))
+      -- trovo l'intersezione tra retta e circonferenza
+      ptInt = EgtIP( nCircle, nLine, ptNewRef)
+      EgtErase( nCircle)
+      -- allungo l'arco per arrivare al punto di intersezione
+      if nArc == nCrv2 then
+         EgtModifyCurveEndPoint( nArc, ptInt)
+      else
+         EgtModifyCurveStartPoint( nArc, ptInt)
+      end
+      
+   else
+      ptInt = EgtIP( nCrv1, nCrv2, ptRef)
+      if not ptInt then
+         -- tento estendendo le curve
          EgtExtendCurveStartByLen( nCrv1, 10000)
          EgtExtendCurveEndByLen( nCrv1, 10000)
          EgtExtendCurveStartByLen( nCrv2, 10000)
          EgtExtendCurveEndByLen( nCrv2, 10000)
          ptInt = EgtIP( nCrv1, nCrv2, ptRef)
-      
-      -- se entrambi archi
-      elseif EgtGetType( nCrv1) == GDB_TY.CRV_ARC and EgtGetType( nCrv2) == GDB_TY.CRV_ARC then
-         -- trovo intersezione tra le due circonferenze
-         local nCircle1 = EgtCircle( GDB_ID.ROOT, EgtCP( nCrv1), EgtArcRadius( nCrv1))
-         local nCircle2 = EgtCircle( GDB_ID.ROOT, EgtCP( nCrv2), EgtArcRadius( nCrv2))
-         ptInt = EgtIP( nCircle1, nCircle2, ptRef)
-         EgtModifyCurveStartPoint( nCrv1, ptInt)
-         EgtModifyCurveEndPoint( nCrv2, ptInt)
-         EgtErase( nCircle1)
-         EgtErase( nCircle2)
-         
-      -- se arco e linea
-      else
-         local nLine = EgtIf( EgtGetType( nCrv1) == GDB_TY.CRV_LINE, nCrv1, nCrv2)
-         local nArc = EgtIf( nLine == nCrv1, nCrv2, nCrv1)
-         -- tento di trovare intersezione prolungando la linea
-         EgtExtendCurveStartByLen( nLine, 10000)
-         EgtExtendCurveEndByLen( nLine, 10000)
-         ptInt = EgtIP( nArc, nLine, ptRef)
-         if not ptInt then
-            -- creo circonferenza corrispondente all'arco
-            local nCircle = EgtCircle( GDB_ID.ROOT, EgtCP( nArc), EgtArcRadius( nArc))
-            -- trovo l'intersezione tra retta e circonferenza
-            local ptDist = EgtIf( nArc == nCrv2, EgtEP( nArc), EgtSP( nArc))
-            local _, ptRef = EgtPointCurveDist( ptDist, nLine)
-            ptInt = EgtIP( nCircle, nLine, ptRef)
-            EgtErase( nCircle)
-            -- allungo l'arco per arrivare al punto di intersezione
-            if nArc == nCrv2 then
-               EgtModifyCurveEndPoint( nArc, ptInt)
-            else
-               EgtModifyCurveStartPoint( nArc, ptInt)
-            end
-         end
       end
    end
    
@@ -123,12 +125,6 @@ local function TrimAndOrientOrderedCurves( vCrvs, bOrient)
       local ptInters = FindIntersectionPoint( vCrvs[i], vCrvs[ nPrevIndex], EgtSP( vCrvs[i]))
       if LastCurveInters then
          LastCurveInters.EndInters = Point3d( ptInters)
-         -- se il punto di intersezione è lo stesso trovato nell'iterazione precedente cerco una seconda
-         -- intersezione tra le due curve
-         if AreSamePointApprox( ptInters, LastCurveInters.StartInters) then
-            ptInters = FindIntersectionPoint( vCrvs[i], vCrvs[ nPrevIndex], EgtEP( vCrvs[i]))
-            LastCurveInters.EndInters = Point3d( ptInters)
-         end
       end
       local NewCurveInters = { CurveId = vCrvs[i], StartInters = Point3d( ptInters)}
       table.insert( IntersCurveList, NewCurveInters)
@@ -1999,7 +1995,7 @@ local function CalcGeoRaw( nPartId)
    -- aggiungo spessore
    local dDimH = EgtGetInfo( nGeoLayerId, WIN_GEOHEIGHT, 'd')
    EgtModifyCurveThickness( nCompo, - dDimH)
-
+ 
    -- creo frame ausiliario
    local vtX = EgtSV( nCompo)
    local frGeo = Frame3d( EgtSP( nCompo), vtX, Z_AX() ^ vtX, Z_AX())
@@ -4684,17 +4680,19 @@ local function CalcWaterdrip( nPartId, nOutlineId, nAreaId, bDraw)
                   local nCopy1 = EgtCopyGlob( nCrv1, nGrp)
                   EgtExtendCurveStartByLen( nCopy1, 200)
                   EgtExtendCurveEndByLen( nCopy1, 200)
-                  local pt1 = EgtIP( nOutlineId, nCopy1, ORIG())
                   local nCrv2 = EgtGetFirstNameInGroup( nSplitGeo, WIN_OUT)
                   local nCopy2 = EgtCopyGlob( nCrv2, nGrp)
                   EgtExtendCurveStartByLen( nCopy2, 200)
                   EgtExtendCurveEndByLen( nCopy2, 200)
+                  local pt1 = EgtIP( nOutlineId, nCopy1, ORIG())
                   local pt2 = EgtIP( nOutlineId, nCopy2, ORIG())
-                  -- salvo i parametri di intersezione
-                  local dPar1 = EgtCurveParamAtPoint( nOutlineId, pt1, 100 * GEO.EPS_SMALL)
-                  local dPar2 = EgtCurveParamAtPoint( nOutlineId, pt2, 100 * GEO.EPS_SMALL)
-                  table.insert( vParams, dPar1)
-                  table.insert( vParams, dPar2)
+                  if pt1 and pt2 then
+                     -- salvo i parametri di intersezione
+                     local dPar1 = EgtCurveParamAtPoint( nOutlineId, pt1, 100 * GEO.EPS_SMALL)
+                     local dPar2 = EgtCurveParamAtPoint( nOutlineId, pt2, 100 * GEO.EPS_SMALL)
+                     table.insert( vParams, dPar1)
+                     table.insert( vParams, dPar2)
+                  end
       
                   -- salvo le sue sottoaree per analizzarle
                   local vChildren = EgtGetNameInGroup( vStack[i], WIN_AREA .. '*') or {}