# Extracting transfer function values after Volume rendering in 3D Slicer

**URL:** <https://discourse.slicer.org/t/extracting-transfer-function-values-after-volume-rendering-in-3d-slicer/6366>\
**Category:** Support\
**Tags:** volume-rendering\
**Created:** [April 2, 2019, 11:49am UTC](https://discourse.slicer.org/t/extracting-transfer-function-values-after-volume-rendering-in-3d-slicer/6366 "2019-04-02T11:49:19Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![nish91](https://avatars.discourse-cdn.com/v4/letter/n/da6949/32.png) [@nish91](https://discourse.slicer.org/u/nish91)\
**Post date:** [April 2, 2019, 11:49am UTC](https://discourse.slicer.org/t/extracting-transfer-function-values-after-volume-rendering-in-3d-slicer/6366/1 "2019-04-02T11:49:19Z")

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I render a NifTI volume using ‘Volume rendering’ module in 3D Slicer as shown in the figure below. However, I would like to replicate exactly the same using python and VTK without using 3D Slicer. For that I need to extract the values of the transfer function used for rendering the volume. Could anoyone let me know how I can achieve that in 3D Slicer?

 ![Selection_095](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/7/7/7782c08b76aa446ee7ac40070bc0ca06e042bf97.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 2, 2019, 12:25pm UTC](https://discourse.slicer.org/t/extracting-transfer-function-values-after-volume-rendering-in-3d-slicer/6366/2 "2019-04-02T12:25:31Z")

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Sure, the code’s all in [the Volume Rendering Module Displayable Manager](https://github.com/Slicer/Slicer/tree/master/Modules/Loadable/VolumeRendering/MRMLDM). Of course consider building on the Slicer code and contributing back improvements if you can.