# 4D straightened volume rendering

**URL:** <https://discourse.slicer.org/t/4d-straightened-volume-rendering/19269>\
**Category:** Support\
**Created:** [August 19, 2021, 7:49am UTC](https://discourse.slicer.org/t/4d-straightened-volume-rendering/19269 "2021-08-19T07:49:34Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![xiaolin](https://avatars.discourse-cdn.com/v4/letter/x/c4cdca/32.png) [@xiaolin](https://discourse.slicer.org/u/xiaolin)\
**Post date:** [August 19, 2021, 7:49am UTC](https://discourse.slicer.org/t/4d-straightened-volume-rendering/19269/1 "2021-08-19T07:49:34Z")

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Hi everyone.  
Warm Greetings.  
This is Xiaolin Sun, a doctoral student in Berlin.  
I am writing this message to ask for your kind help with 4D straightened volume rendering.  
I used the animal cardiac CT to reconstruct the right heart. The CT was reconstructed in every 10% of the cardiac cycle(from 0 to 100%), with this I get the 4D cardiac CT directly. Then I applied segmentation(right heart)-\> Add centerline-\> Curved Planar reformat-\>volume rendering, to get the straightened right heart model. As in the screenshot (right ventricle-pulmonary artery, top-\>down).

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/6/a/6a5fe34f9939cdf6993c4f2a7fa325f8b9a105be.jpeg)  
Furthermore, 4D dynamic heart can be achieved by volume rendering.  
Now, I am wondering how can I get the 4D straightened volume rendering, a beating straightened model. Should I segment every 10% of the cardiac cycle, export the Dicom file, register the 10 frames ( from 0-100 % of the cardiac cycle), or use other extensions? Could you please offer me some detailed guidance to achieve this?

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:** [August 20, 2021, 6:19pm UTC](https://discourse.slicer.org/t/4d-straightened-volume-rendering/19269/2 "2021-08-20T18:19:42Z")

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Volume rendering requires the transform to be hardened on the volume. If you load the 4D cardiac CT as a volume sequence (not as a multivolume) then you can apply and harden the transform on each frame.