# Mask scalar volume vs masking within the registration

**URL:** <https://discourse.slicer.org/t/mask-scalar-volume-vs-masking-within-the-registration/7835>\
**Category:** Support\
**Tags:** registration, masking\
**Created:** [August 1, 2019, 9:20am UTC](https://discourse.slicer.org/t/mask-scalar-volume-vs-masking-within-the-registration/7835 "2019-08-01T09:20:33Z")\
**Posts on this page:** 1\
**Showing post:** 2

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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 5, 2019, 9:10pm UTC](https://discourse.slicer.org/t/mask-scalar-volume-vs-masking-within-the-registration/7835/2 "2019-08-05T21:10:20Z")

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This post should clarify:

> [@Mask volume- segment editor](https://discourse.slicer.org/t/mask-volume-segment-editor/7808/9):
>
> To keep things simple, make the segment cover the region you are interested in. Then, you can us Mask volume effect to blank out the parts outside your region of interest. Yes, this is correct. All effects (Scissors, Surface cut, Paint, etc.) only modify segments. They will not modify any volume nodes. If you blank out a region of a volume, Elastix will still take those voxels into account. This is probably not what you want. To make Elastix ignore certain regions then you can specify mask…

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_[View the full topic](https://discourse.slicer.org/t/mask-scalar-volume-vs-masking-within-the-registration/7835)._