# Question about "Fill value" button in "Crop Volume" module.

**URL:** <https://discourse.slicer.org/t/question-about-fill-value-button-in-crop-volume-module/17061>\
**Category:** Support\
**Tags:** segmentation\
**Created:** [April 13, 2021, 12:59pm UTC](https://discourse.slicer.org/t/question-about-fill-value-button-in-crop-volume-module/17061 "2021-04-13T12:59:16Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Orestis\_Gaides](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/orestis_gaides/32/10635_2.png) [@Orestis\_Gaides](https://discourse.slicer.org/u/Orestis_Gaides)\
**Post date:** [April 13, 2021, 12:59pm UTC](https://discourse.slicer.org/t/question-about-fill-value-button-in-crop-volume-module/17061/1 "2021-04-13T12:59:16Z")

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Hello, I am researcher from Greece. I would like to ask, what does is the meaning of the option “fill value” in “crop volume” module? And what range of values is appropriate? Thanks in advance.

 ![Fill value](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/e/b/ebe24f6cfd54b2aa59082280af78654459fd9235.png)

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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:** [April 13, 2021, 5:32pm UTC](https://discourse.slicer.org/t/question-about-fill-value-button-in-crop-volume-module/17061/2 "2021-04-13T17:32:18Z")

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If the ROI extends beyond the original volume anywhere the new voxels will be set to that fill value. Sometimes, like in CT, you might want it to be an ‘air’ value like -1000.