question on 3ds max and gamma

[jonathan Evans]

A linear image i guess thats the same as working in a linear workflow

 

What i think i have an understanding on is within the quotes

 

" I have been informed that 3ds max you can import an image at a value of 2.2. which i believe tells max to add an inverse to the image which then on the final render adds the value of gamma to 2.2 This only occurs i belive if put the out put value to 1 . When you put the output value to 1 this informs 3ds max to add the correct value of 2.2. to the images when rendered and saved ".

 

 

My qeusion is on the followng : if follow the process which i have mentioned above Does this occur when you render out and save a jpeg format. As ive seen that exr file is the file to save for a true linear workflow

 

the inverse of a jpeg (i.e. 1/2.2 = 0.4545454…). I gather this is because all jpegs and image have linear gamma applied .

 

sorry if te queston is not constructed very well I. Im doing my best to understand the final process . In regards to using the corrrect gamma with in 3ds max for a linear workflow

[jonathan Evans]

a quicker question

 

if you import an image at 2.2 the image has then been inversed by 3ds max (i.e. 1/2.2 = 0.4545454…). for correct gamma later... the final render is set for 1 which then means the process of gamma is applied to value of 2.2 ...

anything which is out putted by the value of 1 has correction of gamma applied = 2.2

if the following above is correct does this mean my final jpeg image will have the correct value of gamma in the final process .

 

 

if i have the above wrong please= can some one inform me ..

 

 

my question is if the following above is correct . Why would i save the file as an exr file have seen files saved as an exr file?

[jonathan Evans]

ive found the answer i believe . The reason its saved as exr file is you can have an option ro save the file as 32 bit file were a jpeg and tifff are at most a 16 bit file meaning there is more data saved in a 32 bit file . meaning more contrast to play with

 

cheers for the reply apoligise for the for the long post

[jonathan Evans]

As this relate to the gamma post i thought i leave this question in this post

 

i cant locate this a hammer option in vray 2.30.01. im using 3ds max 2013 . It to changing the final output of antialiasing to be 2.2 ...

 

see image attached thanks

[jonathan Evans]

I found it i think the followin is attached here

[jonathan Evans]

I have done some test renders to test the gamma in my renders. I have simple set up of of a bottle with a basic diffuse material. No textures i have tested the scans in the default scnline redndering engine and the vray engine .

 

I have been trying to learn about gamma while doing this and how it affects the final output. I have read some articles on working in a linear workflow can give more gamma and contrast darks and lights to use in post production app. I would be probaly using photoshop

 

I have read an article on the 3d total site which is abased here

http://www.3dtotal.com/index_tutorial_detailed.php?catDisplay=1&roPos=1&id=1552&page=2#.VTEqfyFVhHx

 

 

I applied these values in to vray and default scan line render you can see my values below. when ive used the scanline engine i didnt use the v ray frame buffer.

 

I have noticed that i cant realy see that much of a difference. Have i been applying this method corretly . I am not trying to get a photo realistic image from these tests .

 

 

 

My intial reading was that the gamma was applied to the darker bottles.The lighter bottle had no gamma applied

 

 

To explain my intial set up so the rest can be understood. the 3dsmax output gamma is set to value of 1 and the vray gamma is set up to value of 2.2 . I thought this then output the value of 2.2 the final saved image

 

 

I am starting to confuse my self in the process. I intialy thought i had this correct. On all of these value i can add more light by exposure the fstop and other methods available to add a lighter tone .

 

 

I am trying to use the method correctly . By these simple test setups . if any knows the anser to which has gamma applied to value of 2.2 .. my thoughts are the darker bottle have had the value applied from what i have read and the set up

Edited April 17, 2015 by hansolohan

[Francisco Penaloza]

Honestly I would not sweat it about all the gamma stuff. Yes it is more complicated than what it seems. a few years ago it was more complicated, thankfully software are better setup now that the whole process is easy and you don't need to question your self any more.

 

I would recommend to just set your Max to 2.2 everything.

Only if you plan to save images as EXR or HDR. this are float file that will let you control the gamma in post. if so then you can setup the output to 1.0 just to have a peace of mind if you forget to adjust it manually when save the images. The latest releases of 3D Max should control this by it self any ways.

 

If you do post work but not really switch gamma values to the extreme, then you are safe setting everything to 2.2 in Max. You can always overwrite this value when you save your image any ways.

If your main render engine is V Ray, set your gamma to 2.2 and use VRay render buffer you can choose to render mode to "color mapping and gamma and that's all. forget about everything else. V-Ray will render and will apply the correct gamma to everything else and display the image with the gamma 2.2 and you are ready to go.

If you want to work with exr files or adjust your gamma later, then I will recommend to use Color mapping only or do not apply anything, but this is only if you will apply and correct gamma in post saving your file with float values EXR or HDR.

[James Vella]

Francisco is correct mostly, saving to Exr is safe to have your floating point and output with correct gamma. Im going to throw in a technique I learned from Zac Arrato recently - which would otherwise be forbidden in vray 2.4 but hear me out.

 

If you are using max 2015 - Turn off your Gamma LUT in max, this will input all images at their correct gamma (2.2 for photos and 1.0 for photoshop images or bump maps etc). This will also give you a correct value in the diffuse color (and all colors in max). Set your vray color mapping settings to 'use linear workflow' (notice its not deprecated in vray3) and your mode to none (no gamma correction), set the output to 2.2. Check the sRGB button in the VFB to see the 2.2 output curve.

 

You now have a linear setup, input images come in at their set value, output comes out looking like your VFB saving to exr (jpg will come out with 1.0 as if the sRGB button is unchecked).

 

Things to note about having the LUT on and gamma set to 2.2 - you have to de-gamma colors and certain images for say bumps, this is a difficult workflow. For this test turn your LUT on and set the gamma to 2.2, place a dulux color png in your diffuse slot, look at the color, now on the material ball next to it type in the colors into the rgb diffuse slot - notice the difference? This is because your color values are affected by the gamma. This used to be the case with the render clone window too, once you clone the window the second one would have a 2.2 curve applied. Using this workflow keeps everything linear from start to finish.

 

It doesnt matter really as long as your bitmap images come in and out as expected however I find this new workflow simple and effective.

Edited April 18, 2015 by redvella

[jonathan Evans]

I am using 3ds max 2013

 

my current set up is to bring the images in 3ds max at 2.2 .I belive then 3ds max applies an an inverse of inverse of gamma. I have my vray engine set up to out put gamma at 2.2 to apply the gamma. I have not used a texture map on this process yet. i have not seen how this will affect the final render. As i will update my progress on this forum if my texture maps and scene are washed out .

 

thankyou

[RyderSK]

which would otherwise be forbidden in vray 2.4 but hear me out.

(notice its not deprecated in vray3)

 

It was never forbidden or advised against, but it was only legacy approach to simply 'convert' old non-linear scene in non-destructive manner. (which is easier than replacing textures and light intensities)

New scenes should never use this workflow, because it's not workflow at all. It's simple hack.

 

Also, it's still 'deprecated' in the same manner (meaning ill-advised to use), the tooltip is simply shorter.

 

you have to de-gamma colors and certain images for say bumps

 

This only really applies to normal maps, since they use standard file format usually (8/16bit integer files like jpegs/etc..) 3dsMax AutoGamma feature doesn't recognise they should be 1.0, the user has to do it manually

(but some renderer, like Corona, already tell the user if it's wrong and correct it).

Regarding bump maps, specular maps,etc.. which could potentially benefit from being in linear space, it shouldn't be done because users aren't authoring this maps in linear space in first place. I.e since most of these textures were authored in regular 2.2 gamma space, you can continue to use them in gamma space in 3dsMax as well. The point is simply to be consistent and use the same gamma they were authored in, but it doesn't matter which one it is.

 

Regarding 3dsMax color picker. Yes, color picker is linear, while everything else is 2.2 once Gamma/Lut space is selected. Because of this, you can either use VrayColor node which lets you specify gamma space, or you can use free plugins that extend 3dsMax color picker to the same.

 

BUT reinventing the whole workflow to be wrong simply to get around such simple thing ? That's simply wrong and should never be advised to new users, or anyone for that matter.

 

The whole gamma thing is only complicated because people make it complicated, esp. with confusing posts like this above.

3dsMax 2014+ and Vray3.0+ are setup gamma correctly from get-go and shouldn't be tinkered with by beginners unless they specially know why they are doing it. Everything has been automated for user's convenience.

 

They should simply hide gamma completely because this will go forever.

Edited April 20, 2015 by RyderSK

[jonathan Evans]

I ave been using the format which is bringing the images in at 2.2 . Outputting the images at 1.00

when using the 3ds max render . Max applies the inverse of gamma at this value to out put them correct value with the following set up input 2.2 output 1.00

 

when using the vray engine ive been importing the images at 2.2 outputting the images at 2.2 .

 

vray input as max above output has to be changed to 2.2 output in vray settings

 

 

ok i see how this works if i have washed out effect i will update

Edited April 20, 2015 by hansolohan

[James Vella]

They should simply hide gamma completely because this will go forever.

 

Like they did in Maya? (You can essentially do that by turning off the LUT in max) I can see how it can be confusing to a beginner - we have all been there. I would have agreed with you about it being a legacy feature until I tried it (Zac also requested this be left in vray3 after speaking with Vlad). Which setup do you use Juraj? Also which max version? (Max 2012 I setup differently to this)

Edited April 21, 2015 by redvella

[jonathan Evans]

the post was just above your post and it the same set up as they use on 3d total which is called the whole shebang

 

 

I ave been using the format which is bringing the images in at 2.2 . Outputting the images at 1.00

 

 

when using the 3ds max render . Max applies the inverse of gamma at this value to out put them correct value with the following set up input 2.2 output 1.00

 

when using the vray engine ive been importing the images at 2.2 outputting the images at 2.2 .

 

vray input as max above output has to be changed to 2.2 output in vray settings

 

 

 

 

i use this set up same as 3d total

http://www.3dtotal.com/index_tutorial_detailed.php?id=1552#.VTWg7iG4Tcs

[RyderSK]

Han Solo stop complicating things.

 

Vray gamma settings are only for sampling, to be used in conjunction with the gamma modes depending on the output. That is completely other things and I don't want to dig up my write ups on that, but Vray3.0 manual is excellent in describing what they do. [beginners--- > Don't touch]

 

Output file is Gamma 1.0 if you want to output linear (gamma1.0), floating point (16-32bit, not 16bit integer!) file format like OpenEXR, and HDR. Everything else is sRGB/Gamma 2.2 space.

 

Btw 3dsMax is not applying inverse gamma or anything, at any time. Everything is linear, always.

 

In Autodesk Settings

[jonathan Evans]

I have been using srgb space as click the small icon at the bottom of the frame buffer, I have been saving in jpeg as when i saved an exr file at 32 bit the alt of the settings in photoshop was not available When i click the srgb button i have setting 2.2 enabled in the frame buffer.

 

 

i have got these setting from the article below

 

http://renderstuff.com/using-gamma-2-2-cg-tutorial/

Edited April 21, 2015 by hansolohan

[RyderSK]

The "sRGB" button in Framebuffer is to preview correct gamma space. It means you are rendering linear, the framebuffer has linear image in it, and to see it correctly, it is applying gamma 2.2 to it.

If you want to save it as OpenExr (which you should if you're rendering linearly without baking gamma down using Vray gamma modes), you save it as 1.0.

Photoshop/AfterEffects/Etc. will open it again as 2.2.

 

All modern application know how to interpret linear files, at no point, should user apply different gamma.

 

Your Max settings are correct.

[zarato]

Hey all, just thought I'd jump in on this conversation. Firstly, using the Gamma/LUT system in 3DS Max is not a true linear workflow. It's main purpose is to work in a gamma corrected workflow and to show renders in the 3DS Max frame buffer with a gamma correction as it doesn't have the sRGB button like the VFB.

 

Gamma/LUT setup puts your workflow into a Gamma corrected space of 2.2 or whatever you set the number to. Max by default works in a Linear space. Your material editor and colour selectors are Linear by default. You can add a 2.2 Gamma with the check boxes in the Gamma/LUT setup. Now whilst your texture maps will be fine with this setup, it's your colour selectors that are affected the most. See the attached image to show you the difference between a LWF and GCWF.

 

 

As you'll see, your colour selectors work in much tighter bounds in the darker areas. This can be difficult when working with reflection and refraction values.ie. A vaule of 128 (mid grey) in an LWF would be around about 58 (dark grey) in a GCWF. Simple enough to work it out, but do you seriously want to gamma correct your colour selector everytime you're trying to match a colour? I hear, just use a jpg or V-Ray colour, which is fine and a valid point for matching specific colours. However, not the case for reflection, refraction, translucent, bump, noise, etc... You get my point... Anywhere we use a black to white value, you would have to gamma correct the colour selector colour to get the value that is about the equivilant in a GCWF.

 

 

But this isn't necessary when using the V-Ray frame buffer. We can display and save out our renders with the sRGB curve applied.If you turn off the Gamma/LUT setup and render with the V-Ray frame buffer, it'll come down to how you set your colour mapping settings.

 

With the Gamma/LUT setup turned "OFF" try the follow setup for your colour mapping.

 

Set the Type to "Linear Multiply"

Set the Gamma to "2.2"

Set the Dark/Bright Multiplier to "1.0"

Set the mode to "None(don't apply anything)"

Set the "Linear Workflow" checkbox to "On"

 

The Linear Workflow check box applies an inverse gamma correction. You have now rendered in a Linear workspace. The button on the V-Ray frame buffer "Display colours in sRGB space" will apply the sRGB curve to the image, allowing you to view a Gamma corrected image.

 

Note in the above settings I set the mode to "None". If you set the mode to "Colour Mapping & Gamma", you can turn off the "Display colours in sRGB space", as the Gamma & Colour Mapping will be baked into the image.

 

This is just a basic overview and I'll be putting out a tutorial with full details about this very soon.

[RyderSK]

it's your colour selectors that are affected the most.

 

Using ColorPicker plugins or VrayColor(CoronaColorMap,etc..) is much more logical and simpler option than turning off Gamma space for 3dsMax. Every single application on today's market is in gamma space, from Photoshop, to UnrealEngine4. Why again re-invent wheel for single issue ?

 

However, not the case for reflection, refraction, translucent, bump, noise, etc..

 

And which is completely irrelevant. As long as these textures are already authored in gamma 2.2. space (Photoshop, SubstanceDesigner, DDO,etc..), you know what the result will be, because you're creating your textures in this space.

The very only difference would be displace map, if you're creating it yourself by using exact values.

 

I'll be putting out a tutorial with full details about this very soon.

 

This is like 2005 all over again... everyone making their own interpretation of what is "correct", what is LWF,etc...

 

Anyway, you're basically describing regular 'non-baked' linear workflow in Vray. One that has maybe 20 existing tutorials, yours exception being turning 3dsMax gamma space off so you can keep all color pickers and maps in linear mode as well.

 

http://www.pixela-3d.com/tutorials/lwf-settings-for-non-baked-gamma

 

 

The whole "issue" is 3dsMax not being consistent, but solution is never to turn it off. Unreal engine4 and most newer applications smartly give you option for linear floating point values in [0-1] spectrum, and all sRGB/Gamma2.2 values on [0-255], which is the only logical solution. Until 3dsMax adopts this standard, simply using ColorMaps when you need to convert values between space is the correct solution. Or just install plugin.

 

 

Edited April 28, 2015 by RyderSK

[jonathan Evans]

i am currenty working on a room i wil update later . you can provide feed back on gamma values once ive uploaded some examples ok These are just material tests ive created . i will update later the room as these are just material tests ive been working on see attached i will update later . on the gamma progression when i finish the room and need to apply the full render