3.3 color management and batch png renders

[snivlem]

Hi,

With 3.3, I noticed it has been updated to support Maya's new color management.

It works really well both in the gui and batch rendering to exrs - perfectly actually and much better than the linear workflow tickbox.

However I can't seem to find out how to render pngs with correct output.

Currently all the swatches and values render correctly under 3.3 when rendering batch to png, however all the srgb textures have still a .454 value burnt into them regardless of what setting I try and change.

Is there a trick to getting this to work? I have an asset library with icons that are png, so the format needs to be png in order to work.

[yolov]

I think I'm missing something. The problem is when rendering to png, right? Is there some part of the corrections to your textures that are done inside maya that you need to disable or is it something that you wish to disable for the final output?

[snivlem]

Well the renders appear just fine in the GUI. (note sRGB is off in the V-Ray framebuffer).

However with the batch render, with PNG the render is gamma corrected by .45.

This happens despite any of the options V-Ray has with color mapping, it doesn't match up to what is happening with the GUI. I'll post a screenshot if required.

[yolov]

That would help, yes.

[ivaylo.ivanov]

PNGs are always color corrected, since 8-bit images don't have enough resolution to hold linear space colors. The VRAY_WRITE_COLOR_CORRECTIONS =0 env var was added for people that insist writing always in linear space.

[snivlem]

Well here is the example, I just want to write pngs to sRGB when it comes to batch renders.


"Mode" had no effect for me.

As per the screenshot the batched png (displayed using the "Photos" app) has been corrected.

If I use VRAY_WRITE_COLOR_CORRECTIONS =0 will this fix my "issue" for pngs and will it affect exrs?

[ivaylo.ivanov]

"Mode" should be set to "only adaptation". Otherwise the gamma will be baked during the rendering and you can't remove it. Single channel exrs had a bug to always write the color corrections which will be fixed in 3.30.02. This issue is unfixable in prior versions, even with the env var, you will need the new build which will ignore the color corrections by default.

[snivlem]

Thank you.

[snivlem]

Hi,

I'm on the new build but I'm still having issues regardless of settings. I was wondering if I could get something clarified?

See this screenshot;



In the GUI, V-Ray is rendering perfectly. Gamma is burnt in and I don't have to toggle the sRGB switch on in the V-Ray Framebuffer to view it correctly.

However the batch output on the right with the red cross, V-Ray is not applying Maya's color correction rules and the image's textures and color swatches are dark.

In the past, I could just enable "linear workflow" tickbox and what I get in the GUI would equal what I get with the batch render. The batch render would have the gamma burnt into the image.

Now it seems there is a discrepancy between the GUI and batch render when rendering 8bit png files?

PS: The reason I want gamma burnt in is because I'm using these as icons for a model library inside Maya - so it needs to display as sRGB

[vlado]

Can you post that scene here so that we can try to reproduce this here? What are the exact steps to reproduce the issue once we have the scene? What program are you using to view resulting .png files?

Best regards,
Vlado

[waaazoo]

Hi,

Sorry if it's kind of hijack, but I'm having at least a similar problem.
In one project (several scenes), some scenes batch render with the correct gamma (using TGA here), and some with wrong gamma output (both rendering fine in the GUI).
I was comparing the rendersettings and the camera settings, but couldn't find any noticeable difference. Finally, I exported all nodes from the scene that had the wrong output, and imported all this in one of the scenes that had the correct output (cleaning up first, off course), and now it renders with correct output. I still don't see the difference in the settings.
Is there somewhere else I can look ?

Tests are done in Maya2014 with Vray 3.30.01

thanks a lot

[snivlem]

Well, I discovered this was 100% my own fault in the end.

I had a bit of a complicated setup in producing this scene for my assets. In one of the mel scripts i had "linear workflow" checkbox on. So that explained the discrepancy between the GUI and batch render.

Apologies to Chaos Group if I wasted any time.