Loading...
> >

Really Grainy Iray Renders...

SubGeniusZeroSubGeniusZero Posts: 61
edited November 2017 in New Users

Hi guys. I'm new to using Iray for renders (longtime 3Delight user here) and so far I've figured out how to light my scenes (somewhat), and how to control the light in the scene using the Exposure control in the Environment section of the "Render Settings" tab, and using the Luminence control in the Photometrics section of the "Lights" tab. But that's really all I've figured out. Anyway. My Iray renders so far are turning out REALLY "grainy" looking, and I was wondering if anyone could help me. I've got the scene lit with three Ambient lights — two coming in at 45 degree angles to either side of the main characters, and one coming in from the front of them — with their Luminence set to a value of 2500 in the "Photometrics" section of their "Lights" tabs. (Is that too low? Too high?) Then, I've got a Point Light situated behind them, about halfway between them and the "wormhole gateway" thing. Then, behind the wormhole gateway, there is a Spotlight, with its Luminence set to about 3500. Then, there are two Spotlights — one up high and out in front, focusing on the male character from about a 30 degree angle, and another, up high and out in front, focusing on the female character from a similar angle, both with their Luminence set to 2500. I've got the "Environmental Lighting Intensity" is set to "1.1" The Exposure in the "Environemnt" section of "Render Settings" is set to "11.3" right now. I've got my "Max Samples" set to 10,000, the Max Time set to 9,000, and the Noise Degrain Ratio set to .06, the default, with the Radius set to 3. What am I doing wrong?

Front-view.jpg
3840 x 2053 - 1M
Left-view.jpg
3840 x 2053 - 743K
Top-view.jpg
3840 x 2053 - 2M
Persp-view.jpg
3840 x 2053 - 2M
test_render.jpg
3840 x 2160 - 5M
Post edited by SubGeniusZero on

Comments

  • BeeMKayBeeMKay Posts: 7,019

    I'm a bit worried ybout the light settings for thoise ambient lights (or any other lights you have in the scene.

    Could you post the surface settings for your light sources, and the parametrs of the spot light? Also, is "Photometric" set to "On"?

    Also, please check out this thread, I posted some examples about light setting in this and the following posts, maybe that will help you a better idea what you need for your scene:

    https://www.daz3d.com/forums/discussion/comment/1536281/#Comment_1536281

  • jag11jag11 Posts: 885

    I noticed you pixel filter radius is high, default is 1.5. Try lower it down.

  • agent unawaresagent unawares Posts: 3,513

    How high is your convergence ratio? Are you waiting until the render completes?

  • SubGeniusZeroSubGeniusZero Posts: 61
    edited November 2017

    My convergence ratio is set to 99%, and I've reset my Pixel Filter radius down to 1.5, that should help I think. Also, Bee McKay: None of my light is emitted by objects; only Lights, so no Surfaces settings for light emitting objects. Photometric switches are all set to "on". What worries you about the Luminence values? I've attached my latest render, with the Pixel Filter Radius still set to 5, all other settings as I've described them. By the way: I should add that I am rendering on a Mac Pro, so I am only rendering with CPU power. No Nvidia graphics card.

    Dizzy_and_Gadget_Together_Iray_Render_001.jpg
    3840 x 2160 - 3M
    Post edited by SubGeniusZero on
  • agent unawaresagent unawares Posts: 3,513

    Is this a completed, 99% converged render? It legitimately looks like it's only been through a couple iterations.

  • SubGeniusZeroSubGeniusZero Posts: 61
    edited November 2017

    It took over four hours to render. It's been through many iterations. I've got my max time set to 9,000.

    Post edited by SubGeniusZero on
  • TottallouTottallou Posts: 555
    edited November 2017

    4 Hours is probably not long enough for this, many report extremely long times sometimes several days for CPU renders to finish to their satisfaction :(

    Check the log file to see what is ending the render - Look under Help - Troubleshooting - View Log File and look near the botton for something like this - (The part in red is the thing that matters to you)

    Maximum number of samples reached.
    2017-11-25 20:08:16.123 Finished Rendering
    2017-11-25 20:08:16.154 Total Rendering Time: 4 minutes 22.88 seconds

    Once you know whats stopping the render you can change your settings accordingly

    Post edited by Tottallou on
  • BeeMKayBeeMKay Posts: 7,019

    Tottalou has some really good advice there.

    As for the lights, you mentioned ambient lights and you have a linear point light in the scene, maybe this example  will let you know why I am worried about the lumiance.

    Linear Point light behaviour:

    At setting 1500, even though the preview is all nice and shiny, in the actual render you get zero light out of it.

    This is 50.000...

    and this is 500.000:

     

  • SubGeniusZeroSubGeniusZero Posts: 61

    The problem seems to be: "Maximum render time exceeded." So the problem is that I'm not setting the render time high enough. Maybe if I set it to 15,000, or 30,000, and just wait . . .

  • SubGeniusZeroSubGeniusZero Posts: 61

    Bee McKay - you were right about the Lumen values! I tried setting them to the higher proportions in the thousand and now my renders are turning out much better and MUCH more well-lit! Thank you so much!

  • SpottedKittySpottedKitty Posts: 7,232
    SubGeniusZero said:

    Bee McKay - you were right about the Lumen values! I tried setting them to the higher proportions in the thousand and now my renders are turning out much better and MUCH more well-lit!

    Don't forget, if the render quality still isn't as good as you want, there's one more thing you can try. Turn the light values up even more, then use the camera controls in Render Settings>Tonemapping to reduce the render brightness. It's the extra light you need, to reduce the speckling, and as a bonus the render will probably complete a bit faster.

Sign In or Register to comment.