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Sparklies

Jason GalterioJason Galterio Posts: 2,562
edited December 1969 in Technical Help (nuts n bolts)

A technical question where I don't even know how to properly ask the question...

I have noticed that in some renders I get, for lack of a better term, "sparklies." They come in all colors, but usually purple most of the time. They look like a little tiny criss-cross, kind of like an obnoxious compression artifact. Like you would see on a badly processed YouTube video.

They seem to occur in areas of intense processing (transparencies, reflections, etc.) but are not consistent. In other words, re-rendering the exact same picture with no changes at all, will often result in a different arrangement of these sparklies.

Changing light rigs will also cause them to alter. All the models and cameras in the same place, just an entirely different light setup and the sparklies will either disappear or significantly re-arrange.

Also, even odder, if the Render Bucket Order is changed, the sparklies will re-arrange.

It seems evident that there is a memory issue at play, but I can't seem to confirm that either. Does anyone know a way to prevent these from popping up?

Comments

  • Scott LivingstonScott Livingston Posts: 4,340
    edited December 1969

    I'm assuming DAZ Studio? Which version of it are you using?

    I've encountered this when using Deep Shadow Maps. Try changing the shadow settings on your lights to Raytraced. Moving your camera slightly might also help.

  • Jason GalterioJason Galterio Posts: 2,562
    edited December 1969

    DAZ Studio, yes. 4.6, sorry.

    But this is something that I have seen happen since 4.0.

    Usually what I do is re-render using a different Bucket Order. Then the abnormalities are in different places. Layer these two images together and erase the ones on the top level.

    It works, but its annoying and time consuming. Especially if the image takes a long time to render to begin with.

    Changing the camera angle will work, sort of. It usually just moves the abnormalities a bit.

    On a recent image they occurred all along the edge of a "Zombie Splat" model (essentially a puddle model) that was using one of Fisty's liquid shaders. I can see how passing thru the curve of the model would baffle the render. And / or cause a memory issue.

    I have also seen them come up around the edges of hair that is set fine.

    But then changing to a different lighting rig (for example from one of IG's Photo Studio rigs to one of the SpeedLights) will make all the sparklies disappear.

  • Scott LivingstonScott Livingston Posts: 4,340
    edited December 1969

    Legionair said:
    DAZ Studio, yes. 4.6, sorry.

    But this is something that I have seen happen since 4.0.

    Usually what I do is re-render using a different Bucket Order. Then the abnormalities are in different places. Layer these two images together and erase the ones on the top level.

    It works, but its annoying and time consuming. Especially if the image takes a long time to render to begin with.

    Changing the camera angle will work, sort of. It usually just moves the abnormalities a bit.

    On a recent image they occurred all along the edge of a "Zombie Splat" model (essentially a puddle model) that was using one of Fisty's liquid shaders. I can see how passing thru the curve of the model would baffle the render. And / or cause a memory issue.

    I have also seen them come up around the edges of hair that is set fine.

    But then changing to a different lighting rig (for example from one of IG's Photo Studio rigs to one of the SpeedLights) will make all the sparklies disappear.


    It's a 3Delight issue related to Deep Shadow Maps and unfortunately my understanding is we just have to wait for 3Delight to fix it... The best way to avoid them is to use Raytraced shadows instead. I'd guess that the lighting rigs that don't have this issue probably use Raytraced shadows.
  • Jason GalterioJason Galterio Posts: 2,562
    edited December 1969

    Well, seems like I am going to have to take your word for it...

    I discovered that there is no way to change the types of shadows using by the IG Photo Studio lights. DAZ doesn't see them as true lights. And the surfaces for the lights have options for the shadows, but not the nature of them.

  • KeryaKerya Posts: 10,943
    edited December 1969

    Is it still happening with 4.6?
    Because I rerendered some scenes from DS4.5, where I had those sparklies and didn't get them in DS4.6 ... there was a change in the 3Delight version between 4.5 and 4.6.

  • SickleYieldSickleYield Posts: 7,634
    edited December 1969

    Scott-Livingston said:
    Legionair said:
    DAZ Studio, yes. 4.6, sorry.

    But this is something that I have seen happen since 4.0.

    Usually what I do is re-render using a different Bucket Order. Then the abnormalities are in different places. Layer these two images together and erase the ones on the top level.

    It works, but its annoying and time consuming. Especially if the image takes a long time to render to begin with.

    Changing the camera angle will work, sort of. It usually just moves the abnormalities a bit.

    On a recent image they occurred all along the edge of a "Zombie Splat" model (essentially a puddle model) that was using one of Fisty's liquid shaders. I can see how passing thru the curve of the model would baffle the render. And / or cause a memory issue.

    I have also seen them come up around the edges of hair that is set fine.

    But then changing to a different lighting rig (for example from one of IG's Photo Studio rigs to one of the SpeedLights) will make all the sparklies disappear.


    It's a 3Delight issue related to Deep Shadow Maps and unfortunately my understanding is we just have to wait for 3Delight to fix it... The best way to avoid them is to use Raytraced shadows instead. I'd guess that the lighting rigs that don't have this issue probably use Raytraced shadows.

    I use 100% raytraced shadows on everything and I've never seen this artifact at all.

  • Jason GalterioJason Galterio Posts: 2,562
    edited December 1969

    Kerya said:
    Is it still happening with 4.6?
    Because I rerendered some scenes from DS4.5, where I had those sparklies and didn't get them in DS4.6 ... there was a change in the 3Delight version between 4.5 and 4.6.

    It is. But its very unpredictable.

    The same scene rendered twice, with no changes at all, can show a different number and arrangement of these artifacts.

    I've also noted that renders on my laptop are much less likely to have artifacts then renders on my (much more powerful) desktop. With the exact same scene being rendered at each.

    I am going to try and locate an example and post it. It is possible that there are multiple definitions / events at work here.

  • Sentinel-3Sentinel-3 Posts: 52
    edited December 1969

    I assume you just got a 64-bit computer. I noticed that when I bought mine. Use raytraced shadows instead of deep shadow maps and the sparkles vanish. I found that fix and looked no further. It works.

  • SickleYieldSickleYield Posts: 7,634
    edited December 1969

    Sentinel-3 said:
    I assume you just got a 64-bit computer. I noticed that when I bought mine. Use raytraced shadows instead of deep shadow maps and the sparkles vanish. I found that fix and looked no further. It works.

    And once you're on a 64 bit machine with a concomitant amount of cores, deep shadows are a false savings (baking them takes as long as just rendering the raytraced ones unless the scene is really huge).

  • KeryaKerya Posts: 10,943
    edited December 1969

    SickleYield said:
    Sentinel-3 said:
    I assume you just got a 64-bit computer. I noticed that when I bought mine. Use raytraced shadows instead of deep shadow maps and the sparkles vanish. I found that fix and looked no further. It works.

    And once you're on a 64 bit machine with a concomitant amount of cores, deep shadows are a false savings (baking them takes as long as just rendering the raytraced ones unless the scene is really huge).

    Sometimes it is an artistic decision to use deep shadow maps ...

  • SickleYieldSickleYield Posts: 7,634
    edited December 1969

    Kerya said:
    SickleYield said:
    Sentinel-3 said:
    I assume you just got a 64-bit computer. I noticed that when I bought mine. Use raytraced shadows instead of deep shadow maps and the sparkles vanish. I found that fix and looked no further. It works.

    And once you're on a 64 bit machine with a concomitant amount of cores, deep shadows are a false savings (baking them takes as long as just rendering the raytraced ones unless the scene is really huge).

    Sometimes it is an artistic decision to use deep shadow maps ...

    Really? Huh. That's an interesting idea.

  • Lissa_xyzLissa_xyz Posts: 6,116
    edited June 2013

    Legionair said:
    Well, seems like I am going to have to take your word for it...

    I discovered that there is no way to change the types of shadows using by the IG Photo Studio lights. DAZ doesn't see them as true lights. And the surfaces for the lights have options for the shadows, but not the nature of them.

    You do it via the surfaces tab. Select the Photo Studio Lights in the scene, and on the surfaces tab do a search for Raytrace. You should get the option in Light-Accent, Light-Back, Light-Key, and Light-Fill. Make sure it's set to ON in all 4 of those.

    Only other thing I can suggest is to actually post a render where it's happening so we can see and can help you better.

    Post edited by Lissa_xyz on
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