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Iray Canvases

ebergerlyebergerly Posts: 3,255
in The Commons

Has anyone been successful in figuring out the iray canvas stuff? I'm talking about the depth pass and diffuse and specular, which come out as exr files.

I think those are high range files from what I've seen, but I don't know how to bring them down to a normal range so they're not all blown out. 

Thanks.

Comments

  • Richard HaseltineRichard Haseltine Posts: 108,792

    What image editor are you using? Photoshop has a specific command for equalising HDR images - Image>Adjustments>HDR Toning.

  • ebergerlyebergerly Posts: 3,255

    Thanks. I'm trying out the free Nuke compositor. I can't find anything that says HDR toning. I thought maybe the "exposure" or something but that doesn't seem to work.. 

  • Oso3DOso3D Posts: 15,091

    I find in Photoshop the images are usable once I convert them to no more than 16 bit.

    You have a lot of wiggle room to bring down stuff blown out and bring up dark details.

    (I also find, in Photoshop, NIK tools 'tonal range' or 'details' to help in different cases)

  • ebergerlyebergerly Posts: 3,255

    Thanks guys. Maybe I need to run them thru Photoshop first and tone map or convert to 16 bit or whatever, and then bring into the compositor

  • Oso3DOso3D Posts: 15,091

    That's what I generally do.

    Note that the default tone adjustment is 'smart', which can allow some sophisticated tone mapping. But sometimes everything gets washed out.

    I usually look at the default then switch to raw exposure setting (and set it to ~-13) and decide which I like better.

  • ebergerlyebergerly Posts: 3,255

    Excellent. Yeah, I just dropped it in PS and my CS4 doesn't have HDR toning but I just leave it 32 bit and adjust the Exposure. I came up with -12 or so, then looked here and you said -13. smiley

    I'll use -13 cuz I never really compared with correct images and you probably have already. 

    Thanks !!

  • Oso3DOso3D Posts: 15,091

    It can vary with lighting and the effect you want.

  • j cadej cade Posts: 2,310
    (in blender at least) the images containing color information, like diffuse or a light group usually need to be multiplied by .001 to be visible. You definitely don't want to convert them down to 16bits as you will lose information. Depth maps I usually leave as is, I mostly use those to fake DOF and it's more logical for me with unnormalized values. What it's basically spitting out is "this bits 1 meter away, this bit is 3 meters away" sice the view transform is usually only showing values from 0-1, 300 and 1 are both greater than or equal to 1 and so look equally white but the actual data is all still there, just not very visually apparent
  • j cadej cade Posts: 2,310
    Specifically in blender I use a mix node set to multiply and connect in the image map and a black with a value of .001. Nuke should definitely have something similar
  • ebergerlyebergerly Posts: 3,255

    Ahhh, bingo !! Thanks j cade....in Nuke there's a multiplier slider above the image where you can multiply by a number (as you said, .001 works) before display. And then I add an Exposure node and I'm all set. Cool, now I don't have to go into PS 

    Thanks.

  • ebergerlyebergerly Posts: 3,255

    Oh, even better. The reason my Exposure node wasn't working in Nuke is that it only went down to -5. I didn't realize you can enter manually an exposure. So I put -13 and it works great 

  • ebergerlyebergerly Posts: 3,255
    edited October 2017

    So after rendering out most of the canvases or passes or whatever, it seems like even though almost all are EXR files (except Material ID I think) some look like they don't need their exposure to be dropped. Like the Normals. 

    And Specular and Diffuse look downright strange either way. 

    But Distance and Beauty and Environment Lighting need the exposure correction. 

    Is there a rhyme or reason to all of this?

    Post edited by ebergerly on
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