# 3D model shifts when changing smoothing parameters

**URL:** <https://discourse.slicer.org/t/3d-model-shifts-when-changing-smoothing-parameters/36737>\
**Category:** Support\
**Created:** [June 12, 2024, 9:22pm UTC](https://discourse.slicer.org/t/3d-model-shifts-when-changing-smoothing-parameters/36737 "2024-06-12T21:22:23Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![ckolluru](https://avatars.discourse-cdn.com/v4/letter/c/ecccb3/32.png) [@ckolluru](https://discourse.slicer.org/u/ckolluru)\
**Post date:** [June 12, 2024, 9:22pm UTC](https://discourse.slicer.org/t/3d-model-shifts-when-changing-smoothing-parameters/36737/1 "2024-06-12T21:22:23Z")

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I use the grayscale model maker to create an isosurface of my volume. When I change the value of the smooth parameter from 15 to zero, the model shifts slightly in the 3D view. I’ve set the Decimate option to zero. All other parameters are defaults. Please see rendering below.

I’m rendering one output geometry in purple and another in red with some transparency. Viewing is set to perspective mode (default) and the camera angle was set to one of the standard directions (A-P).

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/f/1/f1d2fcdb625d4b2f80a26c5a29766201bfc67366.jpeg)

Any insights on why this is happening?

Thanks,  
Chaitanya

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**Author:** ![pieper](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/pieper/32/8_2.png) [@pieper](https://discourse.slicer.org/u/pieper)\
**Post date:** [June 12, 2024, 9:31pm UTC](https://discourse.slicer.org/t/3d-model-shifts-when-changing-smoothing-parameters/36737/2 "2024-06-12T21:31:47Z")

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Try the latest versions of Slicer. Probably you are seeing the issues described below, which have been fixed.

> [@Accuracy of segmentation smoothing](https://discourse.slicer.org/t/accuracy-of-segmentation-smoothing/34723):
>
> Hello, I am healthcare professional, a general and orthopedic surgeon with over 24 years of active experience. We have been using an FDA approved software for complex surgical planning for the past 8 years. However, due to its increasing cost per seat, we were looking for alternative and free solutions and came across 3D Slicer. I appreciate what Slicer’s existing features provide, and we started evaluating it just a couple of months ago. Besides the great functionalities, I have found subtle …

> **[Slight offset in vtkWindowedSincPolyDataFilter if normalization is enabled](https://discourse.vtk.org/t/slight-offset-in-vtkwindowedsincpolydatafilter-if-normalization-is-enabled/7676/20)**
>
> 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: Left: result when using the old Hamming...

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<div class="post-metadata">

**Author:** ![ckolluru](https://avatars.discourse-cdn.com/v4/letter/c/ecccb3/32.png) [@ckolluru](https://discourse.slicer.org/u/ckolluru)\
**Post date:** [June 15, 2024, 4:06pm UTC](https://discourse.slicer.org/t/3d-model-shifts-when-changing-smoothing-parameters/36737/3 "2024-06-15T16:06:12Z")

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Thanks @pieper, this seems to work.

Upgraded from version 5.6.1 r32438 to 5.6.2.