AOV'S PROBLEM OR CLARIFICATION

[Ranko_Design]

First of all to say hi to community, and to seek a solution...

so, I was using vray for some time, and since arnold was default renderer that is shipping with max it would be shame not to learn it, you know as it was back in days when mentalray was raging trough cgi scene, but having said this, I went to create a simple scene with two cubes and couple of textures as shown :

IT has a skydome light with hdr attached to it, so its hdr lightning, and max's physical camera, textures are created and edited in substance designer, and inserted in standard surface shader (as they stated in arnold integrations, though explanation is for maps from painter but since it's same workflow mettalic/roughness everything is same) with:

1) basecolor = automatic (or srgb)

2) mettalic = override 1.0

3) roughness = override 1.0

4) normal = override 1.0

5) height (if used also override) = 1.0 (but i'm not using height, just 4 of these maps stated above...)

and when I try to set up AOV'S (or render elements whateever you like to call them) well result is a bit confusing... let se :
1) when we put arnold light by default it's intensity =1 ; exposure=8

2) set a camera ev to get a proper exposed render (at least in max rendered frame window, what you see in max when rendering) my cam ev is 15 so it look like this :

but when I try to render aovs with basic stuff direct/indirect diff. ; direct/indirect specular (nothing else since I dont have sss, transmissive, volume surfaces I get something strange...

First set of aov's was rendered with : 1) default exposure in skydome light (8) and camera ev.15 and they are washed out completely as seen (ALL AOV's ARE SET AS EXR 32 BIT SO IT CAN BE ADDED IN PS WITH LINEAR DODGE/ADD)

and i have to put exposure adjusment and to turn it down like -6 to get similar result like in rendered window (above)...

2) second render was made with : exposure in skydome light LOWERED TO 1, and camera ev.8 ( so that I can get normal exposed pic in rendered window inside max) and then I went to render AOV'S and end result is close like it was in max's renderer window but not exact... as you can see:

One on the left lacks I think a bit exposure and maybe a bit of contrast.... so regarding this said, on arnold's site they wrote this : ''3ds Max does not support more recent EXR formats natively, and you may have issues using Arnold generated EXRs in your scenes. EXRs with only one layer should work.'' so i rendered all AOV'S in separate exr's but it's the same situation for both versions of render...

so If anyone from SolidAngle COMPANY IS READING THIS, or anyone from forum if can help > my questions are :

1) Is this the right workflow regarding hdr lightning? meaning lowering the light exposure and setting right cam.ev exposure?

2) does this apply for regular lights or just in case of hdr lightning? I dont know is this a bug, or it's a way that arnold works or I'm missing something here???? Since in Vray you dont have a hassle like this...

3) ONE IMORTANT THING > HOW IN HELL SHOULD I SET A AOV FOR LIGHT?? LET SAY FOR THIS SKYDOME LIGHT? or anyother light... just dont throw some fancy mathematical words, just pure and simple procedure...

JUST DONT POINT AT GENERIC STATEMENT FROM MANUAL SINCE I'VE READ IT AND IT DOESN'T HELP AT ALL...

4) WOULD SOMEONE FROM solidangle or anyone who know a little bit more about aov's to post some tut or pic tutorial for let say this :'' Simply adding together such AOVs is all that is needed for the beauty AOV. The albedo AOVs are not needed to reconstruct the beauty AOV but may be used for example to get just the lighting without the surface texture, by dividing diffuse by diffuse_albedo, or for denoising just the lighting while keeping the texture detail intact.''

How in hell to incorporate this into a post prod. some pictures of workflow would be nice...

Sorry for being so extensive but really could not find any explanation for this particular matter online..

and yes im using :

1) 3ds max 2019 update 1.1 , arnold version is 2.1.945

2) my hardware (if needed) is > i7 5820k, 32gb ram, r9 380x 4gb

so if anyone have a solution many thanks in advance

🙂

[maxtarpini]

Generic statement : AOVs need be linear with no exposure applied.

btw, you don't get generic statements when you don't have generic wrong expectations 🙂

[Ranko_Design]

@Max Tarpini

hi, I guess yes since I have saved them to be rendered as EXR full 32 bit float they are linear when you set up your AOV's (render elements)... everything else is on default... so I don't know if I'm missing something or you are thinking on something else...???? Is there anything that needed to set additionally? As far as I know that is all hassle > when you set a output folder you set a file format to be written (exr) , choose half or full precision and that's it...

[maxtarpini]

It looks it's all fine .. just .. the exposure you set in the camera is then the exposure you have to set back once in post .. because exposure correctly isn't applied to aovs as said above.

[Ranko_Design]

@Max Tarpini

aha, so you are saying that if I set cam.ev let say 8 I have to set it in PS (or other image editing software) to a same negative value -8? right?

1) so this apply with any other light?

2) and light exposure has nothing to do with exposure being applied to AOV'S??? IT COMING FROM A CAMERA f-stop or ev, what ever it may be used...????????

p.s I really did not know that arnold is doing that, as I said as far as I remeber in vray that's not needed to be done, maybe I'm wrong...

[maxtarpini]

light exposure is just light intensity. it's never a problem. of course with some light intensities you need to setup a proper camera to have a beauty image output. however you have to decide at some point if you wanna do that in post or directly in camera.

of course I don't know why ppz wanna output to aovs and then not use them 🙂 maybe because it looks so pro 🙂 .. however as soon as you output to aovs you take the camera beauty rgba pass as a temp output where you setup your shading etc. but the fine work will be done in post.

the problem with 3dsmax is that it is a complete mess 🙂 so you have fstop, exposure gain, global exposure and god only knows what else .. try to use just a plain 'exposure' so you can set it back in ps to get to the overall result you had in 3dsmax and from there fine tweak.

[Ranko_Design]

@Max Tarpini thnks man for anwer,Yeah as I tought so, i've tweaked in the first time exposure in ps, aovs are there, just did not know that camera exposure will effect linear formats, and I was confused... just one question - you said ''plain exposure'' > which one of these two would give me best results (meaning to is to set it up in 3ds max and then to revert value in exposure in ps) :

1) manual (setting up aperture and shutter speed)???

2) ev value since is just one value( nubmer) to play with????

thnks again

[maxtarpini]

can't test it right now but yeah most probably with 'ev' as with 'aperture and shutter speed' you may have a full tonemapper there.

[Stephen.Blair]

Exposure control (eg on a Physical Camera) is not rendered to the AOVs.

If you're rendering EXRs, you get a linear render with no exposure control.

[Ranko_Design]

@Stephen Blair

as I tought so, but when I render it and import renders in PS (I've tried affinity photo just to be sure that it wasn't a photoshop fault, nope same thing) they are overexposed, and then if I move exposure adjusment down then you can see them as they are in max (well not exactly since you can move exposure and tweak it by eyes to match it but not 100% as if they are untouched) ant do some other tweaking...so I don't know what is going on... i set them s 32bit exr (not half float) and that is it... linear is linear... so I'm confused...

[Ranko_Design]

@Stephen Blair

So I have tried with default ROBOT SCENE at their site ( scene contains 3 quad lights) I have set AOV's > diff. direct/indirect ; spec.direct/indirect since it's a simple scene that has a only a robot with metal material. Then results are next :

1) AOV's are linear as seen below :

and after exposure adjusment of 2.5 let's say here we go:

BUT, when I delete 3 quad lights and insert a SKYDOME WITH A HDR TEXTURE HERE AND SET CAMERA EV. TO 16 (just to be able to see in max frame window picture and to tweak samples if needed) here are AOV'S :

AS YOU CAN CLEARLY SEE THAT EXPOSURE ADJUSMENT IS OFF!

AND WHEN I SET MINUS -7.33 EXPOSURE YOU GET SOMETHING ACCEPTABLE AS SEEN :

SO ARNOLD WHEN USING HDR LIGHTNING HAS SOME PROBLEM WITH AOV'S AND EXPOSURE IS EMBEDDED WITH THEM!

Maybe I'm stupid or whatever but that is what is showing with their scene and just replacing quad lights with hdr....

so is it a bug, or it's just bult that way or something that they will correct I don't know, but really if I have to tweak renders to be nearly close as in rendered frame window insted of getting untouched render elements as they are and then just by adding them together, and getting 100% as is in max, well to hell with it...what is the point???

I mean yes, you have control from start to set exposure but I don't know it seems stupid really...

correct me if I'm wrong but it's a hassle really...

[nicola.stefano.jannuzzo]

Ranko, that's just a skydome misbehavior, because it gets created with an intensity exposure of 8, that makes sense for other lights, not really for skydome, that has no decay. Try adjusting that setting.

[Ranko_Design]

@Nicola Jannuzzo

thnks for answer, well yes, best results I've got when light exposure was lowered to 1 and then adjusted the camera.ev parameters, but still some exposure tweaking has to be adjusted, but it's not drastic it's more reasonably like from 2.2 ~ 2.5/2.6, it's just shame that aov's or render elements (whatever we call them) are not acting like in vray {(I'm not favoring it, just some things are very elegantly done but we're here for arnold and overall it's way more straightforward to render anything than vray which has a ton of settings)} meaning when composed aov's and beauty are 100% identical... I even watched MographPlus's tutorial for arnold for 3ds max, and even their tutor at the end had to put like 2.5 gamma in after effects to match edited aov's to beauty...