# What is the difference between 3D volume and 4D volume?

**URL:** <https://discourse.slicer.org/t/what-is-the-difference-between-3d-volume-and-4d-volume/7582>\
**Category:** Support\
**Created:** [July 15, 2019, 8:58am UTC](https://discourse.slicer.org/t/what-is-the-difference-between-3d-volume-and-4d-volume/7582 "2019-07-15T08:58:39Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![kscript](https://avatars.discourse-cdn.com/v4/letter/k/ec9cab/32.png) [@kscript](https://discourse.slicer.org/u/kscript)\
**Post date:** [July 15, 2019, 8:58am UTC](https://discourse.slicer.org/t/what-is-the-difference-between-3d-volume-and-4d-volume/7582/1 "2019-07-15T08:58:39Z")

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Hi.

I looked around the forum and saw a lot of 4D Volume (nrrd file).

I searched to find out about 4D Volume, but I did not know.

What is the difference between 3D Volume and 4D Volume?

Thank you.

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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:** [July 15, 2019, 12:52pm UTC](https://discourse.slicer.org/t/what-is-the-difference-between-3d-volume-and-4d-volume/7582/2 "2019-07-15T12:52:40Z")

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The 4th dimension is often time, but can be diffusion gradients or segmentation. Maybe you can start by looking at [the multivolme support](https://www.slicer.org/wiki/Documentation/4.10/Modules/MultiVolumeExplorer). Feel free to follow up if you have more questions.