# Joint Smoothing in Slicer 4.13 works incorrectly 

**URL:** <https://discourse.slicer.org/t/joint-smoothing-in-slicer-4-13-works-incorrectly/23326>\
**Category:** Development\
**Created:** [May 8, 2022, 2:04am UTC](https://discourse.slicer.org/t/joint-smoothing-in-slicer-4-13-works-incorrectly/23326 "2022-05-08T02:04:14Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Volha](https://avatars.discourse-cdn.com/v4/letter/v/7c8e57/32.png) [@Volha](https://discourse.slicer.org/u/Volha)\
**Post date:** [May 8, 2022, 2:04am UTC](https://discourse.slicer.org/t/joint-smoothing-in-slicer-4-13-works-incorrectly/23326/1 "2022-05-08T02:04:14Z")

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Hello!  
I do the following: run Slicer4.13=\> Segment Editor=\> Smoothing =\> Joint smoothing (1.0) =\> apply. I get the result:

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/d/7/d72e176582ae516ed9e0f1e781ab4a7d5efc0841.jpeg)  
But in Slice v4.11 result is different: ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/e/6/e62345438103ccb7516d225d04840a4077424e6f.jpeg)

Please explain what has changed in Slicer v4.13 compared to Slicer v4.11 for Joint Smoothing?  
How can it be fixed for Slicer v4.13?

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [May 8, 2022, 10:47pm UTC](https://discourse.slicer.org/t/joint-smoothing-in-slicer-4-13-works-incorrectly/23326/2 "2022-05-08T22:47:02Z")

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I can confirm that there is a change in behavior of the joint smoothing. It is due to change in the underlying smoothing filter in VTK. I’ve posted a question on the VTK forum about it:

> **[Mesh internal surface smoothing behavior changed in...](https://discourse.vtk.org/t/mesh-internal-surface-smoothing-behavior-changed-in-vtkwindowedsincpolydatafilter/8446)**
>
> It seems that the rewrite of vtkWindowedSincPolyDataFilter (that amazingly improved its performance) also changed how internal surfaces are smoothed. Smoothing of internal surfaces are important because when we segment a medical image we usually...

In the meantime, you can use other smoothing methods with the `Apply to all segments` option enabled, optionally followed by `Joint smoothing` to reduce gaps between segments.