# Slight offset in vtkWindowedSincPolyDataFilter if normalization is enabled

**URL:** https://discourse.vtk.org/t/slight-offset-in-vtkwindowedsincpolydatafilter-if-normalization-is-enabled/7676
**Category:** Support
**Created:** [January 18, 2022, 11:34pm UTC](https://discourse.vtk.org/t/slight-offset-in-vtkwindowedsincpolydatafilter-if-normalization-is-enabled/7676 "2022-01-18T23:34:59Z")
**Posts on this page:** 1
**Showing post:** 20

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### Author: ![lassoan](https://discourse.vtk.org/user_avatar/discourse.vtk.org/lassoan/32/50_2.png) [@lassoan](https://discourse.vtk.org/u/lassoan)
#### Post date: [March 13, 2024, 12:57am UTC](https://discourse.vtk.org/t/slight-offset-in-vtkwindowedsincpolydatafilter-if-normalization-is-enabled/7676/20 "2024-03-13T00:57:11Z")

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The fix has been integrated into VTK. To illustrate the effect of what has changed, here is the result (in red) of smoothing a bumpy surface (white), generated by the newly added `smoothCylNuttall` test:

![image](https://discourse.vtk.org/uploads/default/original/2X/3/362ea1f2fd601cf9bc5b4afa8a679d59999de389.png)

- Left: result when using the old Hamming window function. Outer surface of the cylinder is mostly white, inside surface is mostly red. This indicates that the surface has slightly shrunk as a result of smoothing.
- Right: result when using the new Nuttall window function. Both the inner and outer surface of the cylinder is uniformly red-and-white, which indicates that the smoothing evened out the bumps without changing the overall size.

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_[View the full topic](https://discourse.vtk.org/t/slight-offset-in-vtkwindowedsincpolydatafilter-if-normalization-is-enabled/7676)._