# How to modify interpolation mesh grids

**URL:** <https://discourse.slicer.org/t/how-to-modify-interpolation-mesh-grids/4211>\
**Category:** Support\
**Tags:** volume\
**Created:** [September 27, 2018, 3:03pm UTC](https://discourse.slicer.org/t/how-to-modify-interpolation-mesh-grids/4211 "2018-09-27T15:03:33Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![baverso](https://avatars.discourse-cdn.com/v4/letter/b/c5a1d2/32.png) [@baverso](https://discourse.slicer.org/u/baverso)\
**Post date:** [September 27, 2018, 3:03pm UTC](https://discourse.slicer.org/t/how-to-modify-interpolation-mesh-grids/4211/1 "2018-09-27T15:03:33Z")

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Hello, I’d like to know if there are any modules which allow me to modify the interpolation grids? Please see the image below for various methods of alignment:

 ![10%20AM](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/4/8/48a5e35321988519de1a2b395bac1b9340cd9886.png)  
Source: Image biomarker standardisation initiative

> **[1612.07003.pdf](https://arxiv.org/pdf/1612.07003.pdf)**
>
> 1827.71 KB

If not in possible in the Slicer GUI, does ITK or VTK support this programmatically? Thank you for any assistance.

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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:** [September 27, 2018, 6:21pm UTC](https://discourse.slicer.org/t/how-to-modify-interpolation-mesh-grids/4211/2 "2018-09-27T18:21:19Z")

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Do you mean changing sampling grid of image volumes? In Slicer, we refer to it as resampling of volumes and there are many modules for this - see details here: [https://www.slicer.org/wiki/Registration:Resampling](https://www.slicer.org/wiki/Registration:Resampling)

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**Author:** ![baverso](https://avatars.discourse-cdn.com/v4/letter/b/c5a1d2/32.png) [@baverso](https://discourse.slicer.org/u/baverso)\
**Post date:** [September 27, 2018, 7:01pm UTC](https://discourse.slicer.org/t/how-to-modify-interpolation-mesh-grids/4211/3 "2018-09-27T19:01:42Z")

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Hi Andras, thank you for your response. I am familiar with the modification of the vowel spacing and various methods of interpolation, and it’s great that this functionality is available through several modules.

Once a volume has been down sampled with interpolation, the newly interpolated grid (as per the upper right picture) would likely represent the placement of the new voxels. If I desired to choose a method of alignment that is featured in the bottom pictures of my post, does a function exist at this time?

I do not believe one does after spending some time examining several resampling modules, but thought it may be worth asking. Perhaps in VTK or ITK?

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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:** [September 27, 2018, 7:26pm UTC](https://discourse.slicer.org/t/how-to-modify-interpolation-mesh-grids/4211/4 "2018-09-27T19:26:05Z")

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> [@baverso](#):
>
> If I desired to choose a method of alignment that is featured in the bottom pictures of my post, does a function exist at this time?

Usually you need to specify the output geometry (image origin, spacing, axis directions), so you can easily implement any alignment strategy that you prefer.

Some modules offer resampling by a scaling factor and they need to choose some alignment strategy. For example “Crop volume” module can rescale the image and it aligns the pixel corners.