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Render Speckles

ac_mr_blondeac_mr_blonde Posts: 100
in Technical Help (nuts n bolts)

Does anyone know how to completely rid a render of the small scatterings of pixels that appear?  They are especially bad on areas that are receiving reflected light or on shadowed skin, and can be bright pinpricks or general graininess.

 

I have turned up render quality to 100, set the converged ratio to 100%, and left renders going for 1000s of iterations.  The first few hundred iterations diminishes the specks, but after that it's basically the same, and I can't get rid of them.

 

Oh, I should mention that this is primarily an issue when rendering with environment ON, dome and scene, dome visible.  With just scene the specks are much reduced.

 

Any suggestions are welcome!  This is driving me nuts.

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Comments

  • DrNewcensteinDrNewcenstein Posts: 816

    Turn off Render Quality
    Set Max Time to 0 (infinite, or number of iterations reached, whichever comes first)
    Set Max Samples to 15000 (max)
     

    Other suggestions: don't use the Environment. Set it to Scene Only, and add emissive light sources (spheres or whatnot with Iray Emissive Shaders on them, set up like a household light bulb (Emissive color to white, Temperature about 4800, Luminance at least 5000, Luminance Units to Watts, and adjust the wattage and the physical position of the light source to get the desired lighting.

    Also, Create a camera pointed at the subject and turn of its Headlamp so only the emissive surface is lighting the scene.

    You can also monkey around with the Tone Mapping, such as f-stop, film speed, shutter speed, and all that, but there's really no way to get more light in a scene without making it brighter.

  • ac_mr_blondeac_mr_blonde Posts: 100
    DrNewcenstein said:

    Turn off Render Quality
    Set Max Time to 0 (infinite, or number of iterations reached, whichever comes first)
    Set Max Samples to 15000 (max)
     

    Other suggestions: don't use the Environment. Set it to Scene Only, and add emissive light sources (spheres or whatnot with Iray Emissive Shaders on them, set up like a household light bulb (Emissive color to white, Temperature about 4800, Luminance at least 5000, Luminance Units to Watts, and adjust the wattage and the physical position of the light source to get the desired lighting.

    Also, Create a camera pointed at the subject and turn of its Headlamp so only the emissive surface is lighting the scene.

    You can also monkey around with the Tone Mapping, such as f-stop, film speed, shutter speed, and all that, but there's really no way to get more light in a scene without making it brighter.

    Changing to max time instead of quality totally did it.

    I was curious about using lights instead of the environment.  I quite like the effect of the environment dome, so I was curious if most folks have abandoned it for setting up lights or if there is still a use for it?  I do have key lights and rim lights on my actors, but I find the environment accentuates those real lights nicely.

  • outrider42outrider42 Posts: 3,679
    Or just use the new denoiser in the 4.11 beta. It is capable of eliminating grain completely without needing to take a deep dive into tone mapping and lighting. You might lose a touch of the fine detail depending on your render settings, so you may have a trade off. It is very much worth checking out to see how you like it.
  • marblemarble Posts: 7,500

    I've started to notice this problem and I'm not sure that I had it to this extent in the past. Perhaps something changed in the beta (4.11.0.236) but I have not updated my NVidia drivers (397.31) in quite a while. As the OP says, it seems to be an issue with certain environment HDR products. If I use the studio type HDR (like Painters Lights which, by the way, seems to have gone from the store) I don't have a problem. Those with scenery or skies seem to give me most trouble.

    I don't fancy extending the render times - one of the main reasons for using the environment, for me at least, is because they tend to render faster. 

  • marblemarble Posts: 7,500
    outrider42 said:
    Or just use the new denoiser in the 4.11 beta. It is capable of eliminating grain completely without needing to take a deep dive into tone mapping and lighting. You might lose a touch of the fine detail depending on your render settings, so you may have a trade off. It is very much worth checking out to see how you like it.

    This tends to soften the details considerably for me. Perhaps I could try a render at a larger size and scale down in post.

  • kenshaw011267kenshaw011267 Posts: 3,805
    I've been getting good results from the denoiser with render quality turned up but I do use actual lights and all that stuff.
  • rmercier88rmercier88 Posts: 1

    Downgrade your video drives, I was getting Speckles too but not after rolling back to January 2021" drivers

     

  • SevrinSevrin Posts: 6,306

    R Mercier said:

    Downgrade your video drives, I was getting Speckles too but not after rolling back to January 2021" drivers

     

    I'm going to go out on a limb and guess that a driver more recent than the January 2021 one wasn't the issue here. 

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