Color Management and Linear Workflow

[pollack]

I accidentally posted this into general and meant to post it here.

Linear workflow options seemed to have changed recently and I'm trying to sort out what the best process is now. I noticed that on the February Vray update that the Linear Workflow option behavior seemed to change and I had to turn it off mid project and try to adapt. Can anyone help me sort out what the best config is with Vray version 3 and Maya 2016 SP6 + ext1 ?

Prior to February I would check linear workflow on so that by default my textures were considered as 2.2 gamma and I'd add a texture input gamma for exlusions. It seemed like at that point the linear workflow would only affect texture files and not materials. The recent version of Vray seems to have changed so that the Material itself is inverse gamma'd (.4545). This is creating different (darker) imagery than if it just adjusts the texture. Just to understand what changed, is this accurate?

Does the Maya 2016 color management system (prefs) interact with Vray properly? Ideally I'd like files to be interpreted as automatically getting a 2.2 gamma if it's a srgb file type and then I add a texture input just for exclusions to this policy. It seems like this is what the new color management system does. If so, how does texture input gamma interact with this system if i set it to srgb. Would that double transform? If I set to linear then it would it be internally applying a .4545?

So what is the best system for proper linear workflow with Maya and vray now? Is it to have the render settings as 2.2 gamma, mode as "don't affect colors only adaptation", linear workflow checkbox off, and maya's color management on? With this setup does it require texture input gamma's for srgb files? What do for linear files like exr?

Thanks,
Sean

[yolov]

The change with vray 3.3 was that we started supporting the color management system in maya 2016 and later. The color management has a contorl to file nodes where you would see a "color space" dropdown where the default is sRGB (which is roughly gamma 2.2). VRay supports some of that color space corrections though - srgb, raw and all that start with "gamma" in the name. In a default case where you would have srgb and with color management enabled - you won't need to enable the linear workflow at all.
The best way to work with color spaces would be to either use the maya color management system or to have it disabled and use texture input gamma attributes (alternatively gamma nodes). The linear workflow option is not a good path since it reverse-corrects some nodes, while it doesn't apply any correction to others, that's why you get the "deprecated" warning for it when it's enabled and you hit render.
The color mapping modes (don't affect colors, only adapation for example) is slightly different in the way it works with sampling and the effect being (or not) applied to the final image. Here's what the description of its modes reads: https://docs.chaosgroup.com/display/...pingParameters