# Adding secondary rays and complex illumination methods to volumetric rendering

**URL:** https://discourse.vtk.org/t/adding-secondary-rays-and-complex-illumination-methods-to-volumetric-rendering/8214
**Category:** Development
**Tags:** proposal
**Created:** [April 5, 2022, 7:21am UTC](https://discourse.vtk.org/t/adding-secondary-rays-and-complex-illumination-methods-to-volumetric-rendering/8214 "2022-04-05T07:21:36Z")
**Posts on this page:** 1
**Showing post:** 21

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### Author: ![lassoan](https://discourse.vtk.org/user_avatar/discourse.vtk.org/lassoan/32/50_2.png) [@lassoan](https://discourse.vtk.org/u/lassoan)
#### Post date: [April 8, 2022, 6:18pm UTC](https://discourse.vtk.org/t/adding-secondary-rays-and-complex-illumination-methods-to-volumetric-rendering/8214/21 "2022-04-08T18:18:26Z")

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> [@will.schroeder](#):
>
> sounds like the basis for a research proposal 🙂 unless it’s already been done

We only have limited information on how cinematic rendering is implemented in various commercial software (only what we can deduce from demos, presentations, etc.) but probably they follow a similar approach (it is fairly trivial).

Note that if segmentation result is a set of non-overlapping segments then it is not always necessary to use multivolume rendering, but RGB color channels can be generated from the segmentation result, which can be combined with alpha channel can be computed using a scalar opacity transfer function:

[https://dl.dropboxusercontent.com/s/l04gdww0l3ftqs1/RGBA-mouse-segment-render.mp4?dl=0](https://dl.dropboxusercontent.com/s/l04gdww0l3ftqs1/RGBA-mouse-segment-render.mp4?dl=0)

(see [Color Volume Rendering: vtkDataArray Indexing - #5 by pieper](https://discourse.vtk.org/t/color-volume-rendering-vtkdataarray-indexing/5695/5))

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