# VTK multi-volume ROI not working

**URL:** <https://discourse.slicer.org/t/vtk-multi-volume-roi-not-working/10000>\
**Category:** Support\
**Created:** [January 29, 2020, 4:47pm UTC](https://discourse.slicer.org/t/vtk-multi-volume-roi-not-working/10000 "2020-01-29T16:47:22Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![fbordignon](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/fbordignon/32/5269_2.png) [@fbordignon](https://discourse.slicer.org/u/fbordignon)\
**Post date:** [January 29, 2020, 5:05pm UTC](https://discourse.slicer.org/t/vtk-multi-volume-roi-not-working/10000/3 "2020-01-29T17:05:20Z")

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@pieper indicated that we need to use the multi-volume if we need to display multiple volumes: [display incorrectly when two volume rendering by3D slicer 4.10.0 - #2 by pieper](https://discourse.slicer.org/t/display-incorrectly-when-two-volume-rendering-by3d-slicer-4-10-0/4669/2)

When I use the GPU ray-casting, I have the same isse as in [display incorrectly when two volume rendering by3D slicer 4.10.0](https://discourse.slicer.org/t/display-incorrectly-when-two-volume-rendering-by3d-slicer-4-10-0/4669)

The top head is always showing in foreground:

![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/e/9/e9f78b4d27f5a352b4dbf9019474d6fda90f148a.png)

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