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Okay, what's wrong here? (Iray Render problem)

DaWaterRatDaWaterRat Posts: 2,885
edited July 2015 in Technical Help (nuts n bolts)

I made up my mind that I was going to keep G3F for Iray.

Today I was finally able to get the morphs for her, so I set up a simple scene.

Everything has the Iray Uber shader.

I have one distant light in the scene, and an hdri sky (not visible) in the environment map... and this is what I'm getting.

I've done a few other Iray renders just fine, so that this is causing problems is throwing me for a loop. if the bars (which are supposed to be shadow, I think) were dark, I'd attribute it to being overlit, but this looks like it isn't reading the shaders right.

Windows 7, Daz 4.8.0.55 64 bit (I haven't updated to the 4.8.059 yet)

Iray_oops.png
800 x 1000 - 756K
Post edited by DaWaterRat on

Comments

  • mjc1016mjc1016 Posts: 15,001
    edited December 1969

    Check the camera(s) and turn off the Headlamp...the 'automatic' setting doesn't pick up all the lights.

    If it's not that, drop the levels on the distant light way down.

    Or check the tone mapping controls...you may have ISO 800 or some wild shutter speed f-stop setting.

  • KhoryKhory Posts: 3,854
    edited December 1969

    drop the levels on the distant light way down.

    I would actually suggest not using a distant light at all. It is like adding a second sun to the scene since you have an hdri already. If you need additional light after you make adjustments to the tone mapping add a photometric light and change it over to one of the mesh shapes (rectangle etc) for broad lighting. The larger the size of the shape the softer the shadows by the way.

  • DaWaterRatDaWaterRat Posts: 2,885
    edited December 1969

    Headlamp was on auto, but turning that off didn't affect anything.

    All tone mapping settings were at default

    Dropped the Distant light to 10% intensity and got this.

    G3F_10%_Light.png
    800 x 1000 - 1M
  • SpottedKittySpottedKitty Posts: 7,232
    edited December 1969

    mjc1016 said:
    If it's not that, drop the levels on the distant light way down.

    I'll second this; I've experimented a bit with distant lights in Iray scenes, and if I use the same sort of Lumen values I've grown used to for mesh lights, it looks as if the sun's parked just outside the window. Turn the Lumen dial way down to 5 or 10 and try a test render, then try slightly higher or lower values to get closer to what you want.
  • DaWaterRatDaWaterRat Posts: 2,885
    edited July 2015

    I decided to drop the distant light and the hdri map and just use the environment tab's sun. Which is what I've done with other Iray Renders anyway.

    Rending now, and while a little darker than I wanted, it at least is lit "Right"

    (I was probably using the HDRI image map wrong anyway, since I don't usually do photoreal. Stopped using UberEnvironment after one or two experiments to see that it was *not* what I wanted, haven't touched an hdri light set since until Iray came along.)

    G3F_Sunlight.png
    800 x 1000 - 1M
    Post edited by DaWaterRat on
  • KhoryKhory Posts: 3,854
    edited December 1969

    HDRI will give you the "ambient/reflected light" from the environment where the image was taken. If it is outdoors it should also have a "spot" that is comparable to the sun. So using an HDRI gives you a unique color combination based on what is in the image. An example would be one with blue sky, trees, green grass and a stone patio. All of those things in the environment would impact how the light reflects off of everything in the scene color wise. The great thing about Iray and HDRI is that it does not add time to the render like they did in 3DL.

    I could be wrong but I think your character is actually shadowed by the prop you used. Were it moved a little the shadow might be avoided.

  • DaWaterRatDaWaterRat Posts: 2,885
    edited December 1969

    Yeah, I'm sure it's shadows from the prop that is making the image darker than I want. I'll either mess with the shutter speed or add a "flash" (That, amusingly enough I was successful with in another Iray test. A spot light just above and behind the camera.)

    What I meant by using the HDRI wrong is that it came in a freebie set with some .hdr files and some more normal (to me) images (.tif, etc.) and I was using the .tif image, since I really have no clue about .hdr files.

    Also in a scene like this, it is difficult (if not impossible) to "see" the sun, since the prop obscures the environment dome (Which I wasn't bothering with anyway), so it's not easy for me to position correctly.

  • KhoryKhory Posts: 3,854
    edited December 1969

    What I meant by using the HDRI wrong is that it came in a freebie set with some .hdr files and some more normal (to me) images (.tif, etc.) and I was using the .tif image, since I really have no clue about .hdr files.

    Because they have less information a .tif is likely to under light the scene. I know I have used some of my old ones and find them to be less bright when used in Iray.

  • DaWaterRatDaWaterRat Posts: 2,885
    edited December 1969

    Khory said:
    What I meant by using the HDRI wrong is that it came in a freebie set with some .hdr files and some more normal (to me) images (.tif, etc.) and I was using the .tif image, since I really have no clue about .hdr files.

    Because they have less information a .tif is likely to under light the scene. I know I have used some of my old ones and find them to be less bright when used in Iray.

    Okay, so should I use the .hdr files in the environment map? or am I hopelessly confused and lost?

  • KhoryKhory Posts: 3,854
    edited December 1969

    Yes, use the hdri. You will get better clearer light. You can also use the aux window set to iray and rotate the hdri and see where there sun is etc

  • DaWaterRatDaWaterRat Posts: 2,885
    edited December 1969

    Okay

    Thanks for all your help on figuring it out. Like I said, I haven't touched HDRI ... pretty much at all before this.

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