Beware of "3ds Max gamma hack"! :( Tweet

[javierluisbravo]

Now this comes activated by default... also magically the nonlinear tone mapping too is on by default with a linear/off preset in the render settings..
and in the octane camera an awfull agfacolor preset? what the hell?

i spent lot of time trying to figure out what happened.. why all now looks different from previous versions...

so to summarize i found 2 ways:

option 1:
=> gamma hack: on
=> nonlinear tone mapping: on with "srgb" response curve

option 2: (like was in 2019 last stable version)
=> gamma hack: off
=> nonlinear tone mapping: OFF // or ON with linear/off preset (which is the same)

with this both options the exr files saves fine (with no srgb applied) while we see it ok (with srgb applied) in the render octane buffer.

which one is the correct to go?
it seems we were working all the time with the wrong settings in max?

Thanks!

[samsue]

Hi javierluisbravo,

I struggle with it too, it's pretty confusing Otoy's gamma system

If you check the "Passes output setup > Save all render passes as a single multi layer EXR and File Type in EXR Linear" option it doesn't matter much, it will always save in Linear 1 Exr with all passes. But it can cause your computations to freeze if your Render is too big and you have too many passes.

You only need to disable 3DS Max gamma hack and Nonlinear Tone mappind and save with Float 32 Bits.

Gamma becomes for viewing/previewing purposes only.

[javierluisbravo]

well.. you are right...

i always did llike you said before because gamma hack off was default and nonlinear was off too by default in the camera imager..

gamma hack on is a mess... (option 1)... i tried it today and no 32bit exr... it's just an 8 bit

so.. i will go on as i did before 2020.1 (2019 versions!)
=> gamma hack off and nonlinear ton mapping off too... ( i don't know why all this is ticked by default in 2020.1 version)

this made me confuse A LOT! Spent lot ot time figure it out til i founded that "gamma hack" was the issue here...

Thanks!

[paride4331]

Hi javierluisbravo,

Gamma/LUT setup:
Enable Gamma/LUT correction
Gamma 2,2
Affect Color selectors on
Affect Material Editor on

Kernel panel setup:
3ds Max gamma hack on

imager panel Render Setup:
non linear tone mapping on
Gamma 2,2
Response Linear/off

Octanecamera imager panel:
Gamma 2,2
Response Linear

[javierluisbravo]

Thanks Paride,

sorry but what you suggested is not working.. at least in 2020.1 (10.09)..

2 exrs here:
https://we.tl/t-tiFQOnrZdb

=> gamma hack off and nonlinear off (as it was the default in OctaneRender_VR_for_3ds_Max_2019.1.5_-_8.15)
(testjavi.exr => if you expose down the exr the highlihgts are perfect

=> paride suggestion: gamma hack on, gamma 2,2, response linear off
(testparide.exr => it's like an 8 bit.. the highlights are not kept if you expose down the exr file)

i can send you the project if you want.

Thanks for you feedback.

[samsue]

If you want to save you have to disable the 3ds Max gamma hack on and the non linear tone mapping on.

[javierluisbravo]

yeah i know... that's the way i am using... as it was in 2019..
.. but why all the defaults are totally wrong when you start a new scene in 2020.1?

and why paride suggested to go the way he did? if when i save an exr file with his suggestion.. the exr is unusuable as has no proper high dynamic range when you expose down.. all highlihgts are dead.

[javierluisbravo]

what i "assume" is happening here..

octane send to 3dsmax framebuffer to save the animation/image => a exr 32 bit linear file... => but it's clamped from 0 to 1..
so that's why the highlights are not kept if you expose down the exr that was save with "paride" settings (gamma hack on and nonlinean on with gamma 2,2 and responde to lineal..)

hope this can be fixed... meanwihle i will work with gamma hack off and nonlinear off too..

my guess is that you are transitioning to an acescg road... and thats why this changes in the defaults.. right?

kind regards

[samsue]

Hi javierluisbravo,

Gamma/LUT setup:
Enable Gamma/LUT correction
Gamma 2,2
Affect Color selectors on
Affect Material Editor on

Kernel panel setup:
3ds Max gamma hack on

imager panel Render Setup:
non linear tone mapping on
Gamma 2,2
Response Linear/off


Octanecamera imager panel:
Gamma 2,2
Response Linear

paride4331, my life got more complicated again.


Gamma/LUT setup:
Enable Gamma/LUT correction
Gamma 2,2
Affect Color selectors on
Affect Material Editor on

Kernel panel setup:
3ds Max gamma hack on /off

imager panel Render Setup:
non linear tone mapping on
Gamma 2,2 / 1.,0
Response Linear/off - sRGB

Octanecamera imager panel:
Gamma 2,2 / 1,0
Response Linear / sRGB



I've tried several combinations, my rendering always comes out with dark gamma.

[javierluisbravo]

my advice

stick with this for now:

Gamma/LUT setup:
Enable Gamma/LUT correction
Gamma 2,2
Affect Color selectors on
Affect Material Editor on
(this is Linear Workflow gobal of 3dsmax)

Kernel panel setup:
3ds Max gamma hack OFF

imager panel Render Setup:
non linear tone mapping OFF
Gamma 1
Response Linear/off (wathever is not affected because nonlinear tone mapping is OFF)

Octanecamera imager panel:
Gamma 1
Response Linear (wathever is not affected because nonlinear tone mapping is OFF)

=> when saving exr is ok
=> when saving jpg be extra carefull that the gamma has to be 2.2 (usually in automatic it saves to 2,2 gamme in 3dsmax if you have the settings in GAMMA/LUT setup as described at the beginning of this post)

hope this helps!