diff --git a/toonz/sources/tnztools/assistant.cpp b/toonz/sources/tnztools/assistant.cpp
index daab0f6..a7d9e88 100644
--- a/toonz/sources/tnztools/assistant.cpp
+++ b/toonz/sources/tnztools/assistant.cpp
@@ -78,8 +78,9 @@ TGuideline::calcTrackWeight(const TTrack &track, const TAffine &toScreen, bool &
       double weight = length*logNormalDistribuitionUnscaled(midStepLength, snapLenght, snapScale);
       sumWeight += weight;
 
-      TPointD ntp = nearestPoint(mid.position);
-      double deviation = tdistance(toScreen*ntp, p);
+      double deviation = tdistance(
+        toScreen*mid.position,
+        toScreen*nearestPoint(mid.position) );
       sumDeviation += weight*deviation;
     }
     prev = p;