Docs on using ACES in Vray 5

[Muhammed_Hamed]

Hi

Would be nice to have a guide on ACES in Vray 5
Vray has the best ACES implementation in my view and the workflow in Maya specially is quite simple. Having an official guide in Vray’s docs is going to be helpful to users

Here is Arnold’s guide on using ACES,

https://docs.arnoldrenderer.com/disp…/ACES+Workflow

It is pretty good mostly and not that long.
I don’t like the example at the end of the page, and the bit about the images looking darker after the conversion is not correct.. but other than that, it is a good guide

I’ve done a guide about ACES in Vray/Modo here.. the workflow is easier now in Vray 5, so no need to use OSL for converting the maps
https://forums.chaosgroup.com/forum/…-vray-for-modo

And here is another guide for Vray Next on ACEScentral

https://community.acescentral.com/t/…-in-v-ray/2780

Thanks!

[KristinIvanova]

Thank you, Muhammed for such a constructive suggestion!

I’ll definitely add it to the list of topics we need to cover. Currently, we are working on some topics specifically for V-Ray 5.

Cheers,

Kristin

[Muhammed_Hamed]

Awesome!

And looking forward to what you guys are working on

[fredsnyder]

@Muhammed_Hamed Thanks for that guide!

I would definitely like to see an official Chaos guide as well. (Maya/Houdini) Collecting information from different web-sources makes things a bit confusing sometimes. And you never know for sure if you’re doing it “right”.

[Muhammed_Hamed]

@fredsnyder Cheers!

​​​​​​​We moved all our projects to ACES since March, we use Vray Houdini/Maya as well
If you have questions about the workflow let me know, until we see official docs on this

[gaia]

@KristinIvanova

Thank you, Muhammed for such a constructive suggestion!

I’ll definitely add it to the list of topics we need to cover. Currently, we are working on some topics specifically for V-Ray 5.

Cheers,

Kristin

Hello, a guide on ACES in Vray is always in work ?

[KristinIvanova]

Hey all,
We have a document explaining the ACEScg workflow in V-Ray 5 now.
You can check it out here: Chaos Docs

Cheers,
Kristin

[oglu]

You sould add that for Textures you need to use Utility-sRGB - Texture and not ACEScg.

From the Arnold Help

The main color spaces for conversion will be:

• Utility-Linear - Rec.709 or sRGB - choose this for Linear images that use the Rec.709 or sRGB primaries/gamut (which are the same).

• Utility-RAW - for images that do not require conversion (scalar masks, Displacement, Roughness).

• Utility-Rec.709-Camera - for sRGB images, 8-16 bit (lightmaps, matte paints), (JPEG, PNG).

• Utility-sRGB - Texture - recommended color space for sRGB image textures 8-16 bit (JPEG, PNG).

[gaia]

@KristinIvanova

Hey all,
We have a document explaining the ACEScg workflow in V-Ray 5 now.
You can check it out here: Chaos Docs

Cheers,
Kristin

oh my bad ! thank you !!!

[yolov]

@oglu

You sould add that for Textures you need to use Utility-sRGB - Texture and not ACEScg.

From the Arnold Help

The main color spaces for conversion will be:

• Utility-Linear - Rec.709 or sRGB - choose this for Linear images that use the Rec.709 or sRGB primaries/gamut (which are the same).

• Utility-RAW - for images that do not require conversion (scalar masks, Displacement, Roughness).

• Utility-Rec.709-Camera - for sRGB images, 8-16 bit (lightmaps, matte paints), (JPEG, PNG).

• Utility-sRGB - Texture - recommended color space for sRGB image textures 8-16 bit (JPEG, PNG).

Those would come as available options only when you use an OCIO config.

[Muhammed_Hamed]

@KristinIvanova Thanks for the post!
You guys did a great job!

I have few suggestions,

1- About this part

V-Ray supports only ACEScg as the primary color space of choice in CGI and not other ACES versions like ACEScc or ACEScct.
The terminology here is not accurate, could say “ACES colorspaces” instead of “ACES versions”
I honestly think you shouldn’t mention ACEScc/ACEScct here, they are intended for color grading.. no one uses them for CGI rendering anyways.

2-About this part

In all cases, in addition to bitmaps, V-Ray converts the light’s temperature settings, the V-Ray Sun & Sky, the VRayTemperature texture and the VRayMtl dispersion to the rendering color space.
Should add VRscans, lens effects and Hair shader to this, it is quite important to let people know they get converted to ACEScg(specially the Melanin in hair shader .. This is something that only Vray can do

3-About this part

Procedural colors are always treated as specified in the rendering color space by Maya, but displayed in your monitor’s color space in the interface.
This is not the case, color picking is specified by the ACES config file.. and users can change it to their liking
For example I changed mine to ACEScg.. so I would be picking my colors directly in ACEScg
By default it is set to Output - Rec709

And this is what I have in the color picker,

4-About this part

The new Frame Buffer in V-Ray 5 provides a filmic tonemap correction in AMPAS mode that emulates the OCIO display transformation, which can be used instead of an OCIO configuration.
This mode doesn’t look anything like using OCIO in the Frame buffer, see here

OCIO, using ACES sRGB view transform,

Filmic Tonemapping, using AMPAS preset

It would be nice to hear from the Devs what exactly this AMPAS preset does.. My workflow is to use the hable preset and play with the curve until I get something that I like(instead of using OCIO in the frame buffer)

6-About this part,

Download the Open Color IO configuration package from GitHub: https://github.com/imageworks/OpenColorIO-Config
This is a very old download link to 1.0.3 version .. it is over 2 years old
Please use this link for the recent ACES 1.2 update
GitHub - colour-science/OpenColorIO-Configs: Color Configurations for OpenColorIO · GitHub

ACES 1.2 or even 1.1 are much better than 1.0.3 version, it solves some issues and adds more useful IDTs

And finally here, the numbering is wrong on the steps

Thank you!

[Muhammed_Hamed]

@oglu

You sould add that for Textures you need to use Utility-sRGB - Texture and not ACEScg.

From the Arnold Help

The main color spaces for conversion will be:

• Utility-Linear - Rec.709 or sRGB - choose this for Linear images that use the Rec.709 or sRGB primaries/gamut (which are the same).

• Utility-RAW - for images that do not require conversion (scalar masks, Displacement, Roughness).

• Utility-Rec.709-Camera - for sRGB images, 8-16 bit (lightmaps, matte paints), (JPEG, PNG).

• Utility-sRGB - Texture - recommended color space for sRGB image textures 8-16 bit (JPEG, PNG).

+1 on this, it is necessary to add it to the thread
It is something that people do wrong on getting started with ACES

[KristinIvanova]

Hey @Muhammed_Hamed , thank you for your feedback - much appreciated!

We’ll take these notes into consideration.

Point 6 + numbering (I see what you did there ) are corrected.

Cheers,
Kristin

[yolov]

@Muhammed_Hamed

@KristinIvanova

3-About this part

This is not the case, color picking is specified by the ACES config file.. and users can change it to their liking
For example I changed mine to ACEScg.. so I would be picking my colors directly in ACEScg
By default it is set to Output - Rec709

And this is what I have in the color picker,

The Maya color picker lets you specify and preview a color in a custom color space, the rendering color space, with and without the display transform applied, yes. But the actual color value is always in the rendering color space. You can check that with a getAttr command. Maybe we can word it better to avoid confusion, but usually the case is exactly that - the underlying color value is always in the same space.

[Morne]

Can we get a similar guide for Max please?

[KristinIvanova]

Hey Morne,

We are working on it.

Cheers,
Kristin

[matthew999]

@Muhammed_Hamed

+1 on this, it is necessary to add it to the thread
It is something that people do wrong on getting started with ACES

Hi @Muhammed_Hamed

if i have a 32bit hdr that is srgb when opened in photoshop, what colour space should i set the file texture node? utility raw or utility srgb - terture?

thanks matt

[Muhammed_Hamed]

@matthew999

Hi @Muhammed_Hamed

if i have a 32bit hdr that is srgb when opened in photoshop, what colour space should i set the file texture node? utility raw or utility srgb - terture?

thanks matt

Utility Linear Srgb
Your HDRI uses a linear transfer function, and photoshop applies an sRGB curve on top to view it correctly
On the other hand, Utility RAW means no conversion is done (it is uses for roughness maps, normal maps…etc)
and Utility sRGB texture, is for 8 bit file formats like JPEG or TIFF (Albedo maps or any color channels).. it is because these files have an sRGB transfer function (burned to them)

Hope this helps you out, let me know

[KristinIvanova]

Hey guys,

Here is the guide for ACEScg worfklow in V-Ray for 3ds Max: Chaos Docs

Cheers,
Kristin

[Muhammed_Hamed]

Looks pretty good!
Thank you