diff --git a/LuaLibs/CalcPaths.lua b/LuaLibs/CalcPaths.lua
index f3cbc30..77cb179 100644
--- a/LuaLibs/CalcPaths.lua
+++ b/LuaLibs/CalcPaths.lua
@@ -469,7 +469,7 @@ local function ComputeTrimSurfWithOverlapsForRibs( vIds, nSrfBase, nSrfExt, dOff
 end
 
 --------------------------------------------------------------------
-local function VerifyRibsIntersection( nRib1, nRib2, nType1, nType2, nSrf1, nSrf2, nGrp, nOffsGrp)
+local function VerifyRibsIntersection( nRib1, nRib2, nType1, nType2, nSrf1, nSrf2, dWidth, nGrp, nOffsGrp)
    
    -- setti interni ed esterni non si possono intersecare per definizione
    if ( nType1 == RIB_TYPE.INTERNAL and nType2 == RIB_TYPE.EXTERNAL) or ( nType1 == RIB_TYPE.EXTERNAL and nType2 == RIB_TYPE.INTERNAL) then
@@ -490,22 +490,23 @@ local function VerifyRibsIntersection( nRib1, nRib2, nType1, nType2, nSrf1, nSrf
    ptInt = EgtIP( nCrv1, nCrv2, ORIG(), GDB_ID.ROOT)
    
    -- se non si intersecano, verifico se si intersecano i loro offset
+   local bFound = false
    if not ptInt then
-      local bFound = false
       local vOffs1 = EgtGetNameInGroup( nOffsGrp, EgtGetName( nCrv1))
       local vOffs2 = EgtGetNameInGroup( nOffsGrp, EgtGetName( nCrv2))
       for i = 1, #vOffs1 do
-         local nOffs1 = EgtCopyGlob( vOffs1[i], nGrp)
-         for j = 1, #vOffs2 do
-            -- porto nel gruppo locale e verifico se intersezione
-            local nOffs2 = EgtCopyGlob( vOffs2[j], nGrp)
-            ptInt = EgtIP( nOffs1, nOffs2, ORIG(), GDB_ID.ROOT)
-            if ptInt then
-               bFound = true
-               break 
+         local nSrfOffs1 = EgtSurfFrFatCurve( nGrp, vOffs1[i], dWidth, false)
+         if nSrfOffs1 then
+            for j = 1, #vOffs2 do
+               -- verifico se intersezione
+               local nRes = EgtCurveWithRegionClassify( vOffs2[j], nSrfOffs1)
+               if nRes == GDB_CRC.IN or nRes == GDB_CRC.INTERS then
+                  bFound = true
+                  break
+               end
             end
+            if bFound then break end
          end
-         if bFound then break end
       end
    end
 
@@ -522,6 +523,8 @@ local function VerifyRibsIntersection( nRib1, nRib2, nType1, nType2, nSrf1, nSrf
          -- nel caso unbounded l'intersezione può essere ovunque
          bInters = true
       end
+   else
+      bInters = bFound
    end
    
    return bInters, ptInt
@@ -655,12 +658,15 @@ local function HandleRibsIntersections( nRibsGrp, LayerParams, nOffsGrp, nRibsPa
       for j = i + 1, #vRibsIds do
          local nType2 = EgtGetInfo( vRibsIds[j], KEY_RIBS_TYPE, 'i')
          
-         local bRibInters, ptInt = VerifyRibsIntersection( vRibsIds[i], vRibsIds[j], nType1, nType2, nSrfOffs1, nSrfOffs2, nGrpTmp, nOffsGrp)
+         local bRibInters, ptInt = VerifyRibsIntersection( vRibsIds[i], vRibsIds[j], nType1, nType2, nSrfOffs1, nSrfOffs2, 0.5 * LayerParams.dStrand, nGrpTmp, nOffsGrp)
          if bRibInters then
             bInters = true
-            
-            local dPar1 = EgtCurveParamAtPoint( vRibsIds[i], ptInt, GEO.EPS_SMALL, GDB_RT.GLOB)
-            local dPar2 = EgtCurveParamAtPoint( vRibsIds[j], ptInt, GEO.EPS_SMALL, GDB_RT.GLOB)
+           
+            local dPar1, dPar2
+            if ptInt then
+               dPar1 = EgtCurveParamAtPoint( vRibsIds[i], ptInt, GEO.EPS_SMALL, GDB_RT.GLOB)
+               dPar2 = EgtCurveParamAtPoint( vRibsIds[j], ptInt, GEO.EPS_SMALL, GDB_RT.GLOB)
+            end
             local _, dParE1 =  EgtCurveDomain( vRibsIds[i])
             local _, dParE2 =  EgtCurveDomain( vRibsIds[j])
             
diff --git a/LuaLibs/CalcToolPath.lua b/LuaLibs/CalcToolPath.lua
index 5d56c5f..4fcdf68 100644
--- a/LuaLibs/CalcToolPath.lua
+++ b/LuaLibs/CalcToolPath.lua
@@ -931,7 +931,7 @@ local function CalcRibsToolPath( nRibsGrp, nTpathGrpId, LayerParams, dCorrZ)
       -- mi sposto dell'altezza layer
       EgtMove( nNewEntId, LayerParams.dLayHeight * LayerParams.vtSlicing, GDB_RT.GLOB)
       EgtModifyCurveExtrusion( nNewEntId, LayerParams.vtSlicing, GDB_RT.GLOB)
-      -- EgtSetColor( nNewEntId, EgtStdColor('GRAY'))
+      EgtSetColor( nNewEntId, EgtStdColor('MAROON'))
    end
   
    -- estraggo i contorni di tutte le superfici di offset