# Scaling Segmentation in 3D space

**URL:** <https://discourse.slicer.org/t/scaling-segmentation-in-3d-space/32784>\
**Category:** Support\
**Tags:** segmentation\
**Created:** [November 13, 2023, 5:50pm UTC](https://discourse.slicer.org/t/scaling-segmentation-in-3d-space/32784 "2023-11-13T17:50:07Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![lena\_b](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lena_b/32/68265_2.png) [@lena\_b](https://discourse.slicer.org/u/lena_b)\
**Post date:** [November 13, 2023, 5:50pm UTC](https://discourse.slicer.org/t/scaling-segmentation-in-3d-space/32784/1 "2023-11-13T17:50:08Z")

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Hello, Is there a feature where you can scale a segmentation? I have used the Warping Tool in the Fiducial Registration Wizard, but for certain objects it requires too many points. Are there x, y, z sliders (for example) in another module where you can scale the size of a segmentation in all three dimensions? Thanks in advance for any help!

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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:** [November 13, 2023, 6:20pm UTC](https://discourse.slicer.org/t/scaling-segmentation-in-3d-space/32784/2 "2023-11-13T18:20:35Z")

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You could put it in a linear transform and type the scale factors in the diagonal of the matrix and then harden the transform.

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<div class="post-metadata">

**Author:** ![lena\_b](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lena_b/32/68265_2.png) [@lena\_b](https://discourse.slicer.org/u/lena_b)\
**Post date:** [November 14, 2023, 3:00am UTC](https://discourse.slicer.org/t/scaling-segmentation-in-3d-space/32784/3 "2023-11-14T03:00:09Z")

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Hi Steve, thanks for the quick response! Where could I type the scale factors?

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<div class="post-metadata">

**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:** [November 14, 2023, 3:05pm UTC](https://discourse.slicer.org/t/scaling-segmentation-in-3d-space/32784/4 "2023-11-14T15:05:37Z")

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You can enter them in the diagonals of the matrix in this interface:

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/3/f/3f07f7829e09faf035a5e073fb998f6ee82fa03c.png)

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<div class="post-metadata">

**Author:** ![lena\_b](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lena_b/32/68265_2.png) [@lena\_b](https://discourse.slicer.org/u/lena_b)\
**Post date:** [November 14, 2023, 8:01pm UTC](https://discourse.slicer.org/t/scaling-segmentation-in-3d-space/32784/5 "2023-11-14T20:01:43Z")

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Thanks for sending the screenshot! I am having trouble getting it to work for my case. The diagonal of the matrix will change the size of the segmentation object? As in, stretching it in the x-dimension (for example).

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<div class="post-metadata">

**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:** [November 14, 2023, 9:11pm UTC](https://discourse.slicer.org/t/scaling-segmentation-in-3d-space/32784/6 "2023-11-14T21:11:54Z")

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For example, here the segmentation (green) has been transformed so that it’s 1.5 x bigger than the MRHead that was used to define it originally.

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/5/c/5cce545d46b9d0e09349779ce7bd8666d84676f6.jpeg)

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<div class="post-metadata">

**Author:** ![lena\_b](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lena_b/32/68265_2.png) [@lena\_b](https://discourse.slicer.org/u/lena_b)\
**Post date:** [November 16, 2023, 10:15pm UTC](https://discourse.slicer.org/t/scaling-segmentation-in-3d-space/32784/7 "2023-11-16T22:15:37Z")

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This is very helpful, thank you! When I use this, it does increase the scale like you mentioned, but it appears to translate the segmentation, is this what you would expect?

 ![Screenshot 2023-11-16 at 5.13.36 PM](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/3/e/3ea3d5eaab99a7ae5bbf7732b3f236762ed21444.jpeg)

 ![Screenshot 2023-11-16 at 5.14.25 PM](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/d/b/db59f5b56bfd7744b2475129c44a737ef108dcbc.jpeg)

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<div class="post-metadata">

**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:** [November 16, 2023, 10:23pm UTC](https://discourse.slicer.org/t/scaling-segmentation-in-3d-space/32784/8 "2023-11-16T22:23:20Z")

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It’s a scale around the origin, so if your segmentation is not centered yes, I would expect it to move. You can center the volume in the Volume Module Volume Information pane with the Center Volume button first. Then you can create a segmentation that will be centered (center of the volume will be at the origin. If you want to control that more you can translate the centered segmentation first so that the center is in the place you want to scale with respect to.