Colour over time

Is it possible to drive colour over time? E.g. I’m using Chsritoph’s custom template to have volumes that get their colour from a projected image. I’d like that colour to change to a constant colour over time now (e.g. everything turns pale orange).
I guess you could make another custom template to achieve that (if so this would be a great advanced tutorial), but would it be possible through the shader?
Also, is it possible to get some sort of age AOV out of the renderer to do the above as a comp step?

Hi Frank,

While both, tracking colors or age are something that seems very easy to do with particles, it is unfortunately not that easy with volumes.

Reason for this is that everything is represented on a (eulerian) grid, opposed to individual points moving through space. This makes it hard for instance to track age, as fluids mix and becomes hard to determine where these properties originated from. This is essentially responsible for the colors mixing quickly and turning into uniform soup.

There are some techniques that can help and improve this, but there is unfortunately no silver bullet when doing this purely on a volumetric grid ( at least to the best of my knowledge ).

In general color based workflows with volumes are possible, but will need better support from our end as its a bit complicated. I see what I can do actually integrate this workflow properly, as the demo color element lacks some of this functionality.


Cool, thanks, I kinda thought that it wouldn’t be as simple but since I know next to nothing about volumes I thought I’d ask.
It was mostly out of curiosity, I don’t actually need this at the moment, so no rush at all with this from my side (simple comp tricks are more than sufficient for that I am currently doing).