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gamma LUT settings 3dsmax

Ruz
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Ruz polycount lvl 666
I am really starting to get annoyed about this, do i actually need to have this enabled or not. If I render with out it enabled and with no exposure control, tnings seems much simpler.
Most times I just render out still image of WIP or stuff for my online folio

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  • low odor
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    low odor polycounter lvl 17
    on my old work computer the LUT settings would sometimes screw up the Normal map colors on certain maps...
  • Mark Dygert
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    I turn it off and save a blank scene to the 'c:/program files/3dsmax/scenes' folder as "maxstart.max", that way it loads up with Gamma/LUT turned off every time I load max or reset it.

    On the odd chance I need it turned on, that setting is saved into that particular max file and turns on when that scene loads.

    They kind of screwed everything up by turning it on by default in max 2012... I guess if you don't have anything new just flip some defaults?

    We had a lot of problems with Gamma/LUT settings not carrying over to BackBurner (Max's default render farm). It was a giant pain in the ass and we gave up on using it and went with other solutions instead, VRay.

    I think they did it because it brightens scenes and fakes bounce lighting quite a bit without having to calculate it? Which you can also do by adjusting the ambient light level from pitch black to gray (rendering, environment, global light, ambient).
  • Ruz
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    Ruz polycount lvl 666
    yeah i just wondered what reason there is for actually using it. BTW i figured out that if you are using normal maps, you have to override the 2.2 setting and leave normal maps on 1.0.
    I am indeed using mental ray and am also trying to learn vray, but they take so long to set up and are very flakey when it comes to skin SSS.
    settings never seem to carry across very well.

    Nice tip re the amibient light Mark, will try that, but TBH i hate the overbirght look you get from vray and MR, everything just gets bleached out including the detail in your Normal Map

    I guees it just a case of me not knowing enough yet to get the best out of these renderers.
    Then there are all these extra controls for exposure which is another can of worms
  • supernekosan
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    supernekosan polycounter lvl 7
    you are all wrong about the gamma. to put it simply the gamma is a degama that is a very crucial thing to do a physicaly correct realistic render..if the gamma is not correctly set you wont be abble to work in a correct linear workflow..+ the calculation of the light in max will be all wrong you should realy take a look at what jeff patton is doing..he is a reference in the world of the mental ray render.

    http://jeffpatton.net/2010/12/mental-ray-faq/
    http://jeffpatton.net/Blog-images/3dsMax_Gamma_JP.pdf
    http://scripts.breidt.net/gamma_correct_v12.pdf

    and try looking zap's stuff to he is the one beind the sss shader in mental ray

    http://mentalraytips.blogspot.ca/

    trying to understand how gamma is working is a key to a good render because its the starting point if your gamma is wrong everyting is wrong..i strongly discourage the use of the abiant option in the environement..at least if you are using mental ray. thath being said if your goal is in game render(directx shader) it doseent mater.

    (sorry about my verry bad english)
  • Kerem
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    Kerem polycounter lvl 5
  • Mark Dygert
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    Supernekosan, the main problem is that they didn't bother to "uncorrect" some of the maps like normal maps, which throws that whole system into chaos. Gamma correcting a normal map messed with the values and creates all kinds of problems that don't need to be there. Of course what you see in game is important and you can ignore the viewport but what was the point of spending a few years creating the Nitrous viewport driver that allows you to see normal maps in the viewport in real time if they are just going to break the way it handles normal maps...

    I think they've fixed it in subsequent versions of max.
  • Noors
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    Noors greentooth
    I don't use nitrous, so i couldn't tell for real time display, but when rendering in linear workflow (which is the correct way to render) with gamma input at 2.2, you have to "manually" override gamma of all normal maps and other "mathematical" maps to 1, so they don't get corrected.
    Or set input to 1 and override diffuse textures at 2.2...

    As for the overbright thing in vray, you might want to learn about color mapping types, though correct gamma should already fix most problems.
  • Eric Chadwick
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    Thanks for the links and info people. Added to the wiki...
    http://wiki.polycount.com/Gamma
  • acitone
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    Everything was fine until I enabled gamma/lut correction at 2.2, as per the supposed expert advice, and now my graphics cards are fucked up. Great. SLI doesn't even work anymore and I'm having the dreaded nvlddmkm bsod. Go figure.
  • Synaesthesia
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    Synaesthesia polycounter
    I'm pretty confident that enabling Gamma didn't destroy your computer. Correlation != causation.
  • Bubba91873
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    Bubba91873 polygon
    Try using gamma 1.8 instead of 2.2, will give you a better contrast to your renders and wont look washed out ie dull. In both MR and Vray.

    And yes, you have to override when importing normal maps with 1.0 gamma.

    Acitone
    If you adjusted your gamma on the monitor to 2.2 it would indeed look very bad.But it wouldn't cuase hardware failure....
  • acitone
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    After enabling Gamma at 2.2 I left Max on idle for hours with my project open and that's when my hardware failed. SLI still doesn't work. If it's a coincidence then it picked a hell of a time. Oh well. The cards still work separately.

    I have Gamma at 1.8 as suggested. 2.2 is washed out indeed and takes too much of the color and shading out of the render. I noticed I still have to override when saving the render, at 1.8.

    So we should import Normals at 1.0, what about Specular?
  • Bubba91873
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    Bubba91873 polygon
    acitone wrote: »
    After enabling Gamma at 2.2 I left Max on idle for hours with my project open and that's when my hardware failed. SLI still doesn't work. If it's a coincidence then it picked a hell of a time. Oh well. The cards still work separately.

    I have Gamma at 1.8 as suggested. 2.2 is washed out indeed and takes too much of the color and shading out of the render. I noticed I still have to override when saving the render, at 1.8.

    So we should import Normals at 1.0, what about Specular?

    Normals should always be imported with override at 1.0 in a linear workflow using gamma correction.
    I would override the spec and gloss maps if present. You don't really want them to be gamma corrected since they are only greyscale maps.

    If your using vray heres a nice "how to making of" guide:
    http://www.treddi.com/app/en/articoli/pagina/199-combine-apc-making-of

    It talks of using 1.8 gamma.
  • Ruz
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    Ruz polycount lvl 666
    I read somewhere that if you use logarithmic exposure and have gamma set at 2.2 it will look too bright. I use this a lot but set my gamma to around 1.62
    the theory is that if you use logarithmic it applies it own internal gamma setting of 2.2 but its a bit borked, hence changing the gamma back to 1.62

    if you use mental ray photographic exposure then it ok to leave it at 2.2 because max will disable the system gamma settings if you enable MR photographic exposure

    seems there are too many permutations to say this the right way to do it.
    I tend to use a MR area light and a skylight and it looks ok.
    Physical lights can work well too, but it just depends what you are trying to achieve

    I only use logarithmic because it make my renders look nicer for some reason:)
    NoteThe mr Photographic Exposure Control contains a built-in gamma corrector (gamma 2.2), but this correction is disabled if the 3ds Maxgamma correction is enabled on the Preferences dialog, letting the Rendered Frame Window apply the view gamma instead.
    The Logarithmic exposure control also has a curve similar to a gamma correction, but unlike the Photographic exposure control, it is not designed to disable its gamma correction when overall gamma correction is on. For that reason, combining gamma correction with the Logarithmic exposure control is discouraged, whereas using it together with the Photographic exposure control is encouraged.
    from max help file
  • Ruz
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    Ruz polycount lvl 666
    acitone I am not sure if you have to override spec, but I tend to overrride glossiness map. Not sure about coloured spec, just leave it the same as diffuse I guess.

    Linear workflow is one of the most pain in the arse things to work with and it seems to confuse almost everyone:)
  • Synaesthesia
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    Synaesthesia polycounter
    Are you sure it isn't because your computer overheated? The chances of a setting in Max causing SLI to stop working is infinitesimal. I'd check your cooling system before you do anything else.
  • .Wiki
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    .Wiki polycounter lvl 8
    Ruz wrote: »
    Linear workflow is one of the most pain in the arse things to work with and it seems to confuse almost everyone:)
    But it gives you more opportunities inside of the postproduction or during the rendering process.

    We are creating all of our textures as linear 16Bit EXR files and also render the final images out as EXR sequences. So you have full control over the colors during the whole process.

    A lot of renders have washed out textures because the import settings are wrong. If you just import SRGB images and render them with gamma correction they get washed.
    I guess in 3dsmax there is a global switch to set how to import images but this is only useful if you are sure all your images have the same colorspace.
  • Xoliul
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    Xoliul polycounter lvl 14
    Don't bother with the shitty built-in system. You should just use a viewport shader that does it all internally.
  • Ruz
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    Ruz polycount lvl 666
    .Wiki
    yeah I get why gamma space 2.2 is required, ie for post production stuff,so you would export your renders with a gamma of 1.0 ,so you can make use of the full colour range of the image - you would then adjust the gamma in your compositing app

    A gamma output of 1.0 would look dark in pshop for example

    BUT for most of us we just need to render out our images for our folio on the web, so burning 2.2 or 1.8 gamma in to your render is normally sufficient.

    So what colour space should games artists be working in ie in photoshop ?
    Most of my textures seeem to be srgb. Do I just get rid of any colour profiles in pshop or just use monior colour.
  • Bubba91873
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    Bubba91873 polygon
    Ruz wrote: »
    .Wiki
    yeah I get why gamma space 2.2 is required, ie for post production stuff,so you would export your renders with a gamma of 1.0 ,so you can make use of the full colour range of the image - you would then adjust the gamma in your compositing app

    A gamma output of 1.0 would look dark in pshop for example

    BUT for most of us we just need to render out our images for our folio on the web, so burning 2.2 or 1.8 gamma in to your render is normally sufficient.

    So what colour space should games artists be working in ie in photoshop ?
    Most of my textures seeem to be srgb. Do I just get rid of any colour profiles in pshop or just use monior colour.

    sRGB
    http://seblagarde.wordpress.com/2011/08/17/feeding-a-physical-based-lighting-mode/
  • Ruz
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    Ruz polycount lvl 666
    cheers for the link Bubba91873, explains quite a few things
  • acitone
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    Xoliul wrote:
    Don't bother with the shitty built-in system. You should just use a viewport shader that does it all internally.

    I saw your name and said to myself "hmm, now where have I seen that name", then it dawns on me! - You have a 3ds Max shader that's pretty awesome. Do you have a working version for 2013/14 yet?

    A question about viewport shaders - do they have effect on the render or just the viewport display of textures?
    Are you sure it isn't because your computer overheated? The chances of a setting in Max causing SLI to stop working is infinitesimal. I'd check your cooling system before you do anything else.

    That's probably what happened. I think maybe it overheated one time too many and that's it for SLI on my machine.

    Also, someone, what is "linear workflow" please?
  • Bubba91873
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    Bubba91873 polygon
    acitone:
    linear workflow is the practice of using gamma correction in your textures inside your choice of 3d modeling software for rendering images and compositing those rendered images in photoshop, nuke after effects etc.
    most peoples computer monitors are not calibrated for linear workflows and your 3d modeling program has to gamma correct that mismatch between what you see on your monitor and what your image actually does look like if that makes sence.
  • shaderfx
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    shaderfx polycounter lvl 9
    For the time being, I am with Xoliul, handle it in your shader directly so you have exact control what gets gamma correction and what doesn't.

    I think the "goal" of linear workflow in 3dsMax is the right goal, but too many ways to accidentally de-gamma textures like normal maps resulting in very poor shading (worse then not using linear space on your color textures)

    That said, if you are very familiar with linear workflow, you can just use the 3dsMax build in tools for it. You just have to make sure that on the file dialog when browsing for textures you make the right choice.
  • Mark Dygert
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    I agree with shaderfx (Kees?), we've started using gamma/linear workflow at work again this time with a much greater understanding and it's helped quite a bit.

    This explains it pretty good http://www.workshop.mintviz.com/tutorials/gamma-correction-and-linear-workflow-explained/

    You do need to be mindful of gamma when picking some textures especially normal maps, like shaderfx said. This is the only place that setting comes up inside of max.

    Gamma%20Override.jpg
    It can be a bit maddening if you don't know about it but need to find it. Most people ignore it as just clutter.
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