Aces result looks wrong- please help. HDR, VRscans..

[emartin8907]

Hi

Getting a weird result with Aces setup. Lighting using only an HDR which is set to RAW.

Here are my maya prefs, my Vray Frame Buffer result, and then the result when I take it into Photoshop and apply the ICCprofile and LUT from Alex Fry's method here (it's the 'second' workflow
in this link) https://forums.chaosgroup.com/forum/...s-in-photoshop
I tried this earlier on a test scene and was able to get a 1:1 match from my VFB to Photoshop, but its not working now on this new car scene.

Why am I getting this result, have I set something wrong in my settings?

I'm not even sure which is 'right' - what I'm seeing in VFB or Photoshop, because the VFB looks very oversaturated...

[emartin8907]

and yes i have read every doc on this and looked at other forum posts. I am not asking for someone to repost links i'm asking for help lol. i have followed the docs and am still getting this wrong looking result and i do not know what i've done wrong because according to these docs i've set it up right as far as i can tell which is why i'm now asking for help beyond these docs.

here are results compared again using grey material override , Left is VFB and right is photoshop rebuild.

[tom_hh]

Hey, you have used both possible settings of acescg. As I read it, you can either set aces under vray rendersettings, or in the prefs, as you did. But then you have to set in the vray rendersettings ("from maya preference settings") and not again acescg. At least that's what the doc says. But I also have problems with the colour space, sometimes the shaders change extremely in relation to each other. Also the doc is unfortunately not really well made. On one picture you can see that under default rules it says srgb, under normal etc, of course raw, in another images then the default rule is acescg (that is right). This was not really explained and confusing for me first. If I take the configfile and set an environment variable, unfortunately everything looks very dark... so really good is different I will switch again back from rec709 until this runs cleanly...

[emartin8907]

hi thanks for your post!

as far as i understand, when you set to Aces in the Render Settings it doesn't care about what you've done in the maya prefs. Or is this wrong?
I had initially been setting this up in maya pefs, but at some point thought maybe I had set something wrong, so I then switched to Aces via render settings thinking that overrides whatever you've done in maya prefs..
In any case, when I switch to default in maya prefs and aces in render settings the results are identical.

[Muhammed_Hamed]

I'm thinking about doing a video on this honestly, it will be helpful
Thing is that Photoshop is not color managed, both methods in my post are hacks to get ACES to work in PS..
I think your Maya settings seem to be correct, only question I have is why did you set RAW as IDT for your HDRI?
Could you please upload your rendered HDRI, saved from the Frame buffer?
I will be able to tell what you did wrong in PS (it seems to be a gamma issue)

[Muhammed_Hamed]

hi thanks for your post!
when you set to Aces in the Render Settings it doesn't care about what you've done in the maya prefs. Or is this wrong?

Correct, just use ACEScg in Vray's settings .. it is enough to tell Vray which Gamut you are using, for things like VRscans, physcial sky, kelvin temperature..etc

[emartin8907]

a video would be very helpful!

I am attaching the saved EXR here, thank you for taking a look

I thought my HDRs color space should be set to RAW, is this not correct?

[Muhammed_Hamed]

Hey,

Here is the correct viewing of your EXR in Nuke, PS and Frame buffer

I thought my HDRs color space should be set to RAW, is this not correct?

Most likely no
If you downloaded the HDRI from web, it uses Linear sRGB color space.. you need to set IDT to Utility Linear sRGB
for Albedo maps that are in Jpeg, you use IDT Utility sRGB texture
For data channels, Normals, bump mapping, Displacment and anything that is greyscale or black and white.. you set this to RAW
Gamut conversion doesn't make a difference for these maps anyways

I hope this is helpful, I will make a video about this soon

[emartin8907]

you need to set IDT to Utility Linear sRGB

I do not see 'Utility Linear SRGB' under Color Space options for my HDR file, only normal SRG (which seems to produce wrong result which still does not match vfb to post result)

[Muhammed_Hamed]

Did you play with your config.ocio file ?
In my Photoshop thread you will find a link to ACES 1.2 that I use
It is newer than 1.0.3 that You used in the screenshots, and it comes with its config file that has all needed conversions

[Muhammed_Hamed]

Like this ,

[emartin8907]

I don't even know how to play with that file Lol.
I am trying 1.2 now, thank you for catching that I didn't notice you were on a different version.
Also that's where I'm looking for the color space but can't find any that start with utility

[emartin8907]

okay so with new aces installed i at least getting a consistent result from my VFB to PS to Nuke. Thank you!

now I'm just not sure how to set my HDR to Utility - Linear - SRGB, how do you get that to show up in the drop down list?

[Muhammed_Hamed]

now I'm just not sure how to set my HDR to Utility - Linear - SRGB, how do you get that to show up in the drop down list?

hmmm, did you setup Maya to use ACES in the color management settings?
Can you show me what options you have in the file node ?

[emartin8907]

do I have to have OCIO env variable enabled? I disabled that because when you do that, it messed up all my Color Picker colors which I have for a lot of materials. https://forums.chaosgroup.com/forum/...er#post1082876
"To work around this, you can unset the OCIO env variable and simply use the built-in ACES support in Maya and V-Ray, which does not perform any additional tonemapping when applying the view transform (i.e. it applies only the Output Device Transform, without the Reference Rendering Transform), or use a custom OCIO config file with an sRGB output that does not include the RRT."


EDIT
Okay so with OCIO env variable enable those extra options show up now in my color space dropdown, and I can now use Utility - Linear - SRGB.

BUT Now I can't use the color picker.

Do you know how I can edit the .OCIO file to 'not include the RRT in srgb output'? I have it opend in my text editor, but am not sure what to change or to what. I see in the first role:' Color_Picking: Output - sRGB' but idk if thats what I should change or to what