# Shifting problem in model slice display
**URL:** https://discourse.slicer.org/t/shifting-problem-in-model-slice-display/41897
**Category:** Support
**Created:** [February 27, 2025, 10:46am UTC](https://discourse.slicer.org/t/shifting-problem-in-model-slice-display/41897 "2025-02-27T10:46:27Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@alientex](https://discourse.slicer.org/u/alientex)
#### Post date: [February 27, 2025, 10:46am UTC](https://discourse.slicer.org/t/shifting-problem-in-model-slice-display/41897/1 "2025-02-27T10:46:27Z")
Hi,
I created a segment and exported it into a model. When I turn on slice display visibility, I notice an extreme contour shift, as shown in the images below.
Why is this happening?
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### Author:  [@cpinter](https://discourse.slicer.org/u/cpinter)
#### Post date: [February 27, 2025, 12:37pm UTC](https://discourse.slicer.org/t/shifting-problem-in-model-slice-display/41897/2 "2025-02-27T12:37:55Z")
The labelmap consists of 3D boxes, and compared to that the surface is a continuous representation. I think simply the slice position you look at is not at the center of the labelmap voxel. Btw I wouldn’t call a half voxel discrepancy extreme. It’s similar to the partial volume effect.
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### Author:  [@MJamal](https://discourse.slicer.org/u/MJamal)
#### Post date: [March 3, 2025, 6:12am UTC](https://discourse.slicer.org/t/shifting-problem-in-model-slice-display/41897/3 "2025-03-03T06:12:36Z")
I am also facing this problem. In my case, it varies from system to system. I tried checking on another system, but I didn’t see the same effect (or shifting issue) there.
Is it system-dependent?
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### Author:  [@lassoan](https://discourse.slicer.org/u/lassoan)
#### Post date: [March 3, 2025, 12:58pm UTC](https://discourse.slicer.org/t/shifting-problem-in-model-slice-display/41897/4 "2025-03-03T12:58:03Z")
Please use the latest version of Slicer, we have managed to reduce the effect of smoothing causing slight shift.
If you have problems with accuracy (some details not accurately preserved) you can always work on a smaller region of interest and increase the resolution of the binary labelmap representation of the segmentation.
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### Author:  [@MJamal](https://discourse.slicer.org/u/MJamal)
#### Post date: [March 4, 2025, 9:10am UTC](https://discourse.slicer.org/t/shifting-problem-in-model-slice-display/41897/5 "2025-03-04T09:10:50Z")
> [@lassoan](#):
>
> Please use the latest version of Slicer, we have managed to reduce the effect of smoothing causing slight shift.
Could you please share the commit link for these changes? I’d like to take a look at it.
> [@lassoan](#):
>
> tpu can always work on a smaller region of interest
Sorry, I didn’t quite understand—what is tpu?
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### Author:  [@lassoan](https://discourse.slicer.org/u/lassoan)
#### Post date: [March 4, 2025, 12:59pm UTC](https://discourse.slicer.org/t/shifting-problem-in-model-slice-display/41897/6 "2025-03-04T12:59:33Z")
> [@MJamal](#):
>
> Could you please share the commit link for these changes? I’d like to take a look at it.
I had to make this fix at VTK level. See all the details here:
> **[Slight offset in vtkWindowedSincPolyDataFilter if normalization is enabled](https://discourse.vtk.org/t/slight-offset-in-vtkwindowedsincpolydatafilter-if-normalization-is-enabled/7676)**
>
> When using vtkWindowedSincPolyDataFilter with NormalizeCoordinates enabled then we have found that smoothing result is slightly shifted when the bounding box of the mesh is changed. (originally reported by a 3D Slicer user here). Example Data...
> [@MJamal](#):
>
> Sorry, I didn’t quite understand
You can reduce the ROI and increase the resolution as described [here](https://slicer.readthedocs.io/en/latest/user_guide/modules/segmenteditor.html#segmentation-is-not-accurate-enough). “Specify geometry” function is described [here](https://slicer.readthedocs.io/en/latest/user_guide/modules/segmenteditor.html#panels-and-their-use).