Daz 3D is part of 
Connect
DAZ Productions, Inc.
7533 S Center View Ct #4664
West Jordan, UT 84084
Licensing Agreement | Terms of Service | Privacy Policy | EULA
© 2025 Daz Productions Inc. All Rights Reserved.
Comments
If these are dark specks, they are unrendered or partially rendered pixels. The darker areas tend to take longer to fully form. As more pixels are fully rendered, the convergence percentage increases. Convergence is a process that involces comparing multiple iterations of light passes, and determining when the pixels from these successive passes are similar enough.
If they are light specks, they are fireflies, which are caused by something else -- typically incompatible settings and specular highlights. As long as you keep the fireflies filter on, all or most of these should eventually go away.
I think by default Daz renders will time-out at 2 hours, although I'm a newbie to DS.
So it would seem that if you want to get rid of this grain you need to let it render longer. Do this in Render settings - Progressive Rendering - Max Time (in seconds).
It's the lack of samples. More samples, less grain. You need hundreds if not thousands of samples to get rid of the grain.
Iray sends little beams of light into the environment and samples what bounces around. So it has to send lots of those little beams around and over time it gets an idea of what is going on. The darker the area, the fewer photons bounce over there.
This is an excellent way to explain it. I'm going to steal it for future use!
The thing to remember...there are really two levels (maybe more) of 'done'. The first is what the preset stop conditions will give...and there's 3 of them, in Studio...time, convergence and iterations. Any/all of them could stop the render with unacceptible 'grain' in it.
The next level is what is acceptible or enough samples have been made that there's practically no noticeable change. This is usually a much longer time to render...and it can be MUCH longer (measured in 10s of hours).
Thanks. Great information. Nice to learn about what is going on. As I thought it's simply the lack of those digital photons getting into the dark areas...so they turn out looking like sand paper. As I'm working in animatoin and loath any render longer than 3 min a frame, I play with tone mapping and F-stop and ISO to boost the light sensitivity.
The real trick I've found is that once I import layers into After Effects, I put a box blur on them and set it to 1. This doesn't affect sharpness too much, but it makes a lot of sandpaper go away.
Sure sign of the 'unfinished' nature of the render...and adding more light will probably be more effective than any camera/tonemapping adjustments.
For animation, you can get away with fewer samples because of how video codecs tend to encode video. When I render for video, I don't worry about the image being as sharp as a still render. So that is something to consider. If the video looks good, that is what is most important. High speed action won't need to be as sharp as a slow moving or stationary shot. There is no magic number, so experiementation is key.
But as mjc1016 says, more light is usually the best. It will render faster, and you could always tone down the light in post.
That is one reason that the persistent deepshadow map bug in 3Delight and other Renderman engines is not considered worth fixing...it's only a problem in still shots, because the nature of video means the 'fireflies' it creates move and are different in every frame...there aren't enough to make it noticeable when viewed as a clip.
Video is a lot more forgiving than a static shot.