aces’ purpose is to help film industry to manage their color input. imagine the number of image capture hardware used, all with different ways of representing captured scenes. than try matching footage from 5d, iphone, red dragon and vfx on top of it. aces makes it easy.
That's true but only one side of the coin. As it's a scene referred workflow, it also allows you to preserve the whole dynamic range of your data all along the pipeline. What's more, the way RRT/ODT handles colorspace conversion gives results way closer to a film response. That's what really matters for us. You should watch this video which shows convincing results :
we have it easy from start - most renderers that we use output basicaly the same stuff: hdr color defined by rgb sRGB primaries, usualy in a form of half float exr.
long time ago Vlado posted on chaos group forums regarding rendering in aces colorspace. and if I remember correctly you should be able to switch to aces in VRayNext. not sure if it’s there yet though.
For a proper ACEScg workflow, you need to pre-convert your color textures and lights to ACEScg colorspace(D60 illuminant). The only issue is that most renderers rely on the 3D software color management which is, most of the time, based on sRGB color space (D65 illuminant). As far as I know, only maya is color managed atm.
Vray next allows you to convert your textures and colors on the fly with an OCIO node. From what I understand, it does not needs any internal changes for the renderer to handle ACEScg data. Indeed, ACES is a linear-encoded color space and as far as you feed the renderer (performing linear operations) with linear data and as far as you're outputting these linear data in a linear file format (exr), everything should work as intended and you should be able to work in ACEScg in your comp software. Renderers should be color space agnostic in that way. But we are not able to convert anything related to color temperatures (sun, skies, lights set by illuminant etc..). That's the only blocker I can see. So if we avoid using these components, I guess we should be able to work in ACEScg with corona (assuming we pre-converted all the color textures to ACEScg). Vlado said he is actually working on native ACEScg support in Vray but I have not seen anything out for now.
Disclaimer: Everything discussed here is based on
MY interpretation/comprehension of the phenomenon involved and might present some inaccuracies or wrong statements.