Corona Ideas Portal
The online platform for Corona users to submit, vote, and collaborate on creative suggestions.
The online platform for Corona users to submit, vote, and collaborate on creative suggestions.
It would be useful if we could control volumes in a similar way to lightmix multipliers and the caustics multiplier. Particularly if it could have specific volumes assigned to specific spinners with tint etc.
This would allow us to tweak the perceived density of volumetric materials and volume grid objects without needing to re-render.
PS - this is the equivalent to LightMix and how you can do it in post, you just Linear Add the various LightSelects, and then use an Exposure and / or Tint modification layer on each LightSelect to adjust the brightness and / or color of the light(s) in that LightSelect, which works just fine when it comes to lighting as you are working with a 2D effect by this point in time :)
I am not sure this would do what you want it to do. Bear in mind that volumetrics are a 3D calculation, the ray steps through the scene, and at each step it calculates how much is absorbed, how much is scattered, and then the ray (and the scattered rays) continue to do that, and this is what determines how dense and how bright the volumetric effect is at any point.
Like the caustics intensity multiplier, this has to be done before rendering (and indeed is done, by adjusting the absorption, scattering, and emission of the volume material).
Anything done in the VFB would have to be only a 2D effect, and would not be a realistic adjustment to the volume. Attaching two files, one is rendered with a particular volume absorption distance (3) and then adjusted in post (rebuilding the beauty via Linear Add of all CESSENTIAL render elements, and using an Exposure modification layer on the Volumetrics layer), the other has the absorption distance doubled (to 6) before rendering.
You can see that in the "actual change to the absorption distance" version, the light can be seen to penetrate more deeply into the volume, while in the simulated one (which would be all that could be done with a Lightmix-style process) the effect is nowhere near the same. I couldn't get anything close no matter how I adjusted Exposure, Gamma Correction, Offset, and layer opacity.
So with that in mind, is this really something useful?