Proper ACEScg workflow

[justini]

VRayOCIO can probably help you here?

I don't understand how to use this map. I've tried but it's super confusing. Are you familiar with it's use?

[olly]

I've only recently started using ACES, but I believe the correct setup is like this:



Left image shows the setup for color maps (diffuse/reflection/translucency/textured lights etc)
Right image show the setup for data maps (bump/normal/displacement/roughness etc)
You also need to have your OCIO config setup as described in the docs

If someone more versed in all this spots anything wrong, please let me know!

I hope that helps?

[thomas_bussey]

Just having my first play with this Aces thing. On first glance I liked what it's done with the highlights in my scene but my colours have become way off. I ran the VrayBitmap converter and then Lele's colourswapper script. Is it just me or does that change all diffuse maps to AcesRGB primaries/inverse gamma 0.45? The Mograph VrayMasterclass says I should be setting these to sRGB/from 3dsMAX (possibly the same as 0.45 inverse)

I'm using my previous assets which I'm 99% sure are in sRGB colourspace, so I'll want that option for my RGB primaries (in diffuse) right?

Edit: I chose the wrong option in the script! [facepalm]

[^Lele^]

Lele's colourswapper script.

I had forgotten about it entirely, eheh.
Is it working as intended?

[thomas_bussey]

I had forgotten about it entirely, eheh.
Is it working as intended?

There are a couple of quirks: in a multisubtex it only affects the map in the default slot. it sets (leaves) the rest as 'default'. Docs say this means no transform will be applied (no suffix on my filenames currently), so those textures won't be converted to Acescg colourspace right?

Also in that multisubtex's subtextures it's set the transfer function as 'Auto' which I think is fine as they're 8bit images so = gamma correction.

Directly plugged textures seem to be as follows:
Diffuse: sRGB primaries / 0.45 inverse Gamma
Reflection etc: Default primaries / 0.45 IG
Normal maps: None/Raw

I think strictly speaking refl./refr. maps are supposed to be treated as linear? But in this case I've set things up in the old way of using an 8 bit sRGB image and just adjusting values to suit, so probably not a problem that they're gamma corrected. The fact that they're not getting converted to Aces is possibly more of an issue* though I doubt it'll make a percievable difference.

*That's if I've understood that correctly, that the point of defining the colour space of a texture is so Vray can convert it to the rendering colour space at render time?

[^Lele^]

Great feedback, Thomas, i can work with it, thanks so much.

*That's if I've understood that correctly, that the point of defining the colour space of a texture is so Vray can convert it to the rendering colour space at render time?

It helps thinking it as "interpretation": the data is agnostic on disk (i.e. it's just some bytes for each pixel.), when loaded V-Ray needs to know what it actually represents.
So it's not a conversion (if you load an sRGB-encoded image as ACEScg it'll simply look wrong.), but the correct way to interpret what the image means.
It of course has to tie in with the global color space to make sense (no point loading ACES textures to render in sRGB).

[francomanko]

Can we get a sticky on the correct settings and workflow? This is rapidly becoming something you have to delve into multiple threads to find out?

[thomas_bussey]

Great feedback, Thomas, i can work with it, thanks so much.


It helps thinking it as "interpretation": the data is agnostic on disk (i.e. it's just some bytes for each pixel.), when loaded V-Ray needs to know what it actually represents.
So it's not a conversion (if you load an sRGB-encoded image as ACEScg it'll simply look wrong.), but the correct way to interpret what the image means.
It of course has to tie in with the global color space to make sense (no point loading ACES textures to render in sRGB).

Got it, I think... would there be any point (and is it even possible) to render in an Aces global colour space with sRGB textures? That's what I'm doing and there seems to be some gains in highlight retreival, but would like to know if I've got it all wrong. Is what you're saying is there's no point rendering in a smaller space than your textures have? Presumably the important thing is Vray knows how the texture was created (sRGB ot other colour space) so that it can accurately reproduce it.

I wonder wouldn't it be neater to pick up on an sRGB ICC tag, which most maps will already have, rather than suffixing everything?

Hey arcmos thanks for the tip, I already have that pixamoon script so hopefully an updated version of that willmake managing things easier.

[^Lele^]

Can we get a sticky on the correct settings and workflow? This is rapidly becoming something you have to delve into multiple threads to find out?

We'd love feedback on this documentation page.

[francomanko]

yeah for example i think maybe it would be useful to have the information about which bitmaps settings should be used? Based on what Muhammed_Hamed mentioned. in this post...

https://forums.chaos.com/forum/v-ray...space-dropdown

Also if there are any issues with multisubtex etc, some mention of that etc? Just so its kind of all in one spot instead of multiple threads, or at least linked in the docs?

thoughts?

[Muhammed_Hamed]

We have plans to update the documentation page for ACES setup(Max/Maya/Houdini), I'm discussing the changes with the docs team
The bitmap settings will be part of it, and some new comparison links
More info on color picking as well

Best,
Muhammed

[arcmos]

We have plans to update the documentation page for ACES setup

v2 please

[GLASS-CANVAS]

BTW this thred is the perfect example of why V-Ray badly needs a 'single-button' setup for ACEScg. One click and everything from bitmaps to OCIO LUTs are taken care of.

[^Lele^]

The host application needs changing as well, unfortunately, for that to happen.
It will in the future, but we're not at liberty to say any more, yet.

[^Lele^]

I'm a bit embarassed: the script i posted was very broken, it lacked an entire chunk of code for v-ray colors, and the recursion was quite terrible.
I had v 002 fixed on the same day as v 001, and even zipped and ready for upload, but it never made it to the forum, somehow.

alas, here it is, any feedback is welcome.

EDIT: script removed. do not use it if you previously downloaded it.