# Volume rendering presets

**URL:** <https://discourse.slicer.org/t/volume-rendering-presets/6255>\
**Category:** Development\
**Tags:** volume, volume-rendering\
**Created:** [March 23, 2019, 5:38pm UTC](https://discourse.slicer.org/t/volume-rendering-presets/6255 "2019-03-23T17:38:39Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![erlendb](https://avatars.discourse-cdn.com/v4/letter/e/ec9cab/32.png) [@erlendb](https://discourse.slicer.org/u/erlendb)\
**Post date:** [March 23, 2019, 5:38pm UTC](https://discourse.slicer.org/t/volume-rendering-presets/6255/1 "2019-03-23T17:38:39Z")

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Hi!  
I’m trying to understand the values in the preset file used in Volume Rendering.  
The preset file is found by searching “preset” in …Program Files/slicer…

For instance, why is there 5 values in gradientOpacity, and what are the different values?  
Is there a transferfunction or shader that explains these settings?

Thanks in advance!

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<div class="post-metadata">

**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:** [March 23, 2019, 5:53pm UTC](https://discourse.slicer.org/t/volume-rendering-presets/6255/2 "2019-03-23T17:53:33Z")

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See specification of .vp file [here](https://www.slicer.org/wiki/Documentation/Nightly/Modules/VolumeRendering#Format_of_Volume_Property_.28.vp.29_file). The page also describes how to specify custom volume rendering presets.