# Incorrect volume rendering bounds - first and last slice

**URL:** <https://discourse.slicer.org/t/incorrect-volume-rendering-bounds-first-and-last-slice/17827>\
**Category:** Development\
**Tags:** volume-rendering\
**Created:** [May 27, 2021, 2:10pm UTC](https://discourse.slicer.org/t/incorrect-volume-rendering-bounds-first-and-last-slice/17827 "2021-05-27T14:10:59Z")\
**Posts on this page:** 1\
**Showing post:** 5

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**Author:** ![alireza](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/alireza/32/67173_2.png) [@alireza](https://discourse.slicer.org/u/alireza)\
**Post date:** [May 28, 2021, 1:11pm UTC](https://discourse.slicer.org/t/incorrect-volume-rendering-bounds-first-and-last-slice/17827/5 "2021-05-28T13:11:15Z")

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I created a repo with python implementation here. I’m seeing similar behavior.

I took the example from [here](https://kitware.github.io/vtk-examples/site/Python/Medical/MedicalDemo4/) and adapted it.

It is using `vtkFixedPointVolumeRayCastMapper` for the volume mapper. Is there any other type of volume mappers available in vtk python? and what does slicer use?

I wanted to create a google colab, but vtk is not rendering there for some reason (probably rendering)

> **[sedghi/vtk-volume-render-bounds-bug](https://github.com/sedghi/vtk-volume-render-bounds-bug)**
>
> Contribute to sedghi/vtk-volume-render-bounds-bug development by creating an account on GitHub.

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