# Segmentation not working when changing reference volume

**URL:** <https://discourse.slicer.org/t/segmentation-not-working-when-changing-reference-volume/24643>\
**Category:** Support\
**Created:** [August 4, 2022, 1:40pm UTC](https://discourse.slicer.org/t/segmentation-not-working-when-changing-reference-volume/24643 "2022-08-04T13:40:10Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![bserrano](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/bserrano/32/17034_2.png) [@bserrano](https://discourse.slicer.org/u/bserrano)\
**Post date:** [August 4, 2022, 1:40pm UTC](https://discourse.slicer.org/t/segmentation-not-working-when-changing-reference-volume/24643/1 "2022-08-04T13:40:10Z")

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Hi all,

I segmented some structures using a cropped volume from a bigger one. I realized that I wanted a bigger volume so I cropped the original again. However, the segmentation I had is not working in the new area.  
 ![imagen](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/a/6/a6bc0a99f5cf28a8aad5bf24ee49350a83223dcb.png)  
I can’t use tools outside the original area (green). How can I fix this? I tryied to change the master volume but if I do “mask volume” it does not work. I tryied to create another segmentation node and copy the segment but nothing. I’m becoming a bit crazy.  
Slicer version: 4.11.20210226

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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:** [August 4, 2022, 1:48pm UTC](https://discourse.slicer.org/t/segmentation-not-working-when-changing-reference-volume/24643/2 "2022-08-04T13:48:57Z")

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You could try setting the segmentation’s geometry to match the uncropped volume.

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**Author:** ![bserrano](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/bserrano/32/17034_2.png) [@bserrano](https://discourse.slicer.org/u/bserrano)\
**Post date:** [August 4, 2022, 2:02pm UTC](https://discourse.slicer.org/t/segmentation-not-working-when-changing-reference-volume/24643/3 "2022-08-04T14:02:18Z")

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I tried but I’m experimenting a weird behaviour cause other tools like logical operators or mask volume stop working properly.

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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:** [August 5, 2022, 5:05pm UTC](https://discourse.slicer.org/t/segmentation-not-working-when-changing-reference-volume/24643/4 "2022-08-05T17:05:44Z")

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If you can provide step-by-step description (or screen capture video) of the unexpected behavior then we can investigate. In the meantime, after your change the segment geometry, you may try to apply smoothing to all segments to force using the new geometry.

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**Author:** ![bserrano](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/bserrano/32/17034_2.png) [@bserrano](https://discourse.slicer.org/u/bserrano)\
**Post date:** [August 5, 2022, 9:20pm UTC](https://discourse.slicer.org/t/segmentation-not-working-when-changing-reference-volume/24643/5 "2022-08-05T21:20:04Z")

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Here are the steps:

1- Open volume. Let’s call it _volume_.  
2- Crop volume to obtain a smaller one. Let’s call it _smallCroppedVolume_.  
3- Segment croppedVolume. Here I have several segments.  
4- Crop _volume_ again but this time we obtain a bigger one, _bigCroppedVolume_.  
5- Try to segment _bigCroppedVolume_. Realize that tools only work on the area of _smallCroppedVolume_.  
6- Change geometry and master volume to _bigCropppedVolume_. Now paint tool works but if I try to mask _bigCroppedVolume_, then it does not work.

It seems to work when applying smothing. Is there a way to apply smoothing and then undo the results (with code), so I don’t want to modify the segments.

Many thanks