Iray - Which settings are causing transparent eyes?
linvanchene
Posts: 1,382
I noticed that some Genesis 8 female Iray skins render with transparent eyes.
Can someone help me to learn which settings to adjust to fix this myself?
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I created a simple test scene with Genesis 8 female and a ringlight created from a torus.
With that basic setup everything renders fine.
Result with Genesis 8 female:
Unfortunately when I apply the skin of some custom characters they eyes collect fireflies and then start to become transparent.
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I attached the ringlight test scene with Genesis 8 Female from the Starter Essentials.
https://www.daz3d.com/forums/uploads/FileUpload/55/5949e69e60b5c48416ec6facfc1d94.zip
Keep everything in the scene the same and apply different Iray Skin materials to G8F to find out which characters render with transparent eyes and which not.
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I now tested several characters of the same artists and they all render with transparent eyes.
Characters from other artists render properly with the same scene.
I am at this point interested in actually learning how to fix this issue myself by adjusting the proper material settings.
1) Can someone tell me which settings need to be adjusted to be able to render those characters without transparent eyes?
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Comments
No idea if it may be related, but I recall seeing something in a 'eye product' that noted that 'if eyes go transparent when no background behind figure' change SSS mode from Chromatic to Mono
Thank you. Had not looked into that yet.
Switching the Sclera material from Choromatic to Mono did not fix it though.
All I can observe is that after switching to mono at first some of the "Transmitted Color" values are picked up as well.
A few minutes of rendering later the whole eye is full of white fireflies as well.
The firefly filter is on btw.
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Update / Edit:
Submitted as
Request #270433
Maybe DAZ3D staff has an idea what exactly is causing this.
Some values do this when the SSS Type is sset to Chromatic - setting it to Mono, or enabling Draw Dome avoids the issue. It won't always happen with Chromatic SSS, but I don't know that anyone has figured out the pattern for triggering it.
I made some quick tests with "Draw Dome" enabled.
Scene and Dome default
Scene and Dome with black image set as environment map
There is still something off with the eyes compared to other character skins but now at least the extreme fireflies and the transparency are gone.
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So yes, enabling the dome seems to get rid of the fireflies.
But this then also means that iray seems to need a manual background set up to calculate proper results.
As far as I know other render engines just "simulate" or "assume" a black background if the user does not have one set manually.
Maybe the temporary solution is in this case to always manually set background and then to use render canvases again to render out just the character without background...
In the long run I really hope the DAZ team is forwarding some information to the Iray Developers in order to adress such limitations.
I don't know if this is a shader bug, a DS, bug, an Iray bug, or the way one of the foregoing reacts to impossible combinations of settings. Hopefully if it is a bug it will be fixed.
I don't think it is a bug, it is a shader settings problem, I prefer to use Mono instead of Chromatic for SSS Mode for skin. I recommend turn off Translucency and enable Thin Wall just for Eyes. The eyes got affected by skin translucency it does not absorbs enough light and this light ends up affecting the eyes.
This is a comparison of skin settings, the custom shader(Shader Mixer) involves absorption, the other two are the default for the most recent characters, just changed the SSS Mode, clearly Chromatic Mode improves absorption but still falls short. The Mono Mode is uniformily translucent.