display gamma in RT

[zeronove]

I see; will have to think of something for this particular configuration - basically you get the gamma correction applied twice (once from the V-Ray color mapping, and once from the 3ds Max Display gamma).

Best regards,
Vlado

why twice???

Since he has max output gamma to 1, VRay color mapping "don't affect colors" unchecked and he doesn't use sRGB button, to me everythig should fine, isn'it?
...or am I losting again into LWF maze

Edit 1: The only "twice gamma" issue happens cloning VFB into max FB

[vlado]

Yeah, but the 3ds Max display gamma is set to 2.2, and it is this one that is applied to the ActiveShade window.

Best regards,
Vlado

[zeronove]

Yeah, but the 3ds Max display gamma is set to 2.2, and it is this one that is applied to the ActiveShade window.

Best regards,
Vlado

mmh, I see

let me summarize a bit

max display gamma affects Max Frame Buffer and Active Shade
max display gamma DOESN'T affect VRay Frame Buffer so we use gamma in VRay Color Correction

because of RT using Active Shade, he has max display gamma + VRay Color Correction gamma = twice gamma

is it correct?

[vlado]

This is correct, yes.

Best regards,
Vlado

[simmsimaging]

For that configuration wouldn't it work to just toggle on "adaptation only" for RT renders? In other words actually using LWF?

I work in linear and use Max input/output at 2.2, Vray's gamma at 2.2, and 'adaptation only'. This gives me LWF and with the sRGB button on I get a match in the VFB to what I get in the Max FB, and in RT. No problems at all.

If I want to end up in 8bit or 16bit with my finals I still render with LWF, just save the final image out to a non HDR format (or more usually I just render in linear and convert in Photoshop later). This way I have only one workflow for everything.

b

[devin]

For that configuration wouldn't it work to just toggle on "adaptation only" for RT renders? In other words actually using LWF?

I work in linear and use Max input/output at 2.2, Vray's gamma at 2.2, and 'adaptation only'. This gives me LWF and with the sRGB button on I get a match in the VFB to what I get in the Max FB, and in RT. No problems at all.

If I want to end up in 8bit or 16bit with my finals I still render with LWF, just save the final image out to a non HDR format (or more usually I just render in linear and convert in Photoshop later). This way I have only one workflow for everything.

b

I tried your suggestion changing max output to 2.2, switching to sRGB space and using adaptation in with linear color mapping. Although the results are close they aren't exact, what settings did the beta testers use?

[simmsimaging]

I was a beta tester and those are the setting I used. Not sure about the others, but they are unlikely to be all the same.

Not sure what would be causing any minor differences, but maybe make sure your VFB adjustments are all off (curves, exposure etc.) just to be safe. Also make sure you do not have "linear workflow" toggled on with that input gamma setting.

b

[devin]

I'm not sure what this means but if I save out a rendered image from the VFB and do a print screen of the VrayRT window and open them both in Photoshop they are the same. However while I'm in 3D Studio looking at both the VFB and VrayRT windows the two images are different, the VrayRT image is much lighter.

[rmejia]

These are the settings I use for LWF, and that do not give me problems with RT or cloning to the Max Frame Buffer:
- First image are the 3ds Max Gamma settings
- Second image is regular gamma settings for a brightly lit area, gamma at 1.0
- Third image is for renders with a lot of dark areas and shadows, gamma at 2.2 but with the "Don't affect colors (adaptation only)"
- Fourth image is the VRay frame buffer with the sRGB button activated, a clone of the window to the Max frame buffer, and the V-Ray RT window

[simmsimaging]

Sounds like you are getting double-gamma corrected in Max. Post a screen cap of your camera settings tab and your gamma preferences and maybe something will be obvious.

b

[devin]

Here ya go.

[simmsimaging]

Pretty subtle difference really - I thought it was more pronounced than that. Not sure that I would see that as a problem really. Am I missing something?

b

[devin]

I guess there's no point if we're not concerned with accuracy, if VrayRT can't produce a quick accurate result then that should be stated. I've been working under the assumption that it was capable of rendering the same colors, tones, hues, and saturation levels as Vray's main engines. If this isn't possible I'd like to know.

[rmejia]

What are you using as your primary render engine? Brute force?

[devin]

primary is IR secondary is LC