How to use Additional.xyz grid in Volumes tab

[ziconic]

The Volumes tab lets you specify Additional.x/Additional.y/Additional.z grids to be assigned as Absorption/Scattering/Emission. Does anyone know how these are intended to be used and how they are different from specifying the grid names directly? I don't see these options in the docs (for any plugin) or in the Standalone app, and it's confusing that they let you specify a vector input for Absorption/Scattering/Emission considering that the Volume Medium only works with float values for these quantities.

It would be great if Volume Medium supported vector Absorption/Scattering grids for rendering colored smoke, but as far as I can tell, this doesn't work even when using the Additional.xyz grids.

[juanjgon]

The additional grids is a custom feature added after a request from a studio that needed to render the velocity grids for a scientific visualization project.

Thanks,
-Juanjo

[ziconic]

Thanks for the reply. Do you happen to know if the rest of us can benefit from this custom feature too? In other words, is there a way to read vector data in the volume shader and do something with it?

[juanjgon]

I'm not sure, to be honest. The only useful task for this feature was rendering the velocity or other vector data grids from scientific simulations, but I'm not sure if there are other projects where this feature could be useful.

Thanks,
-Juanjo