Skin turns black in patches in Iray.

[slitherhence]

So two things jump out at me right away.

1. there's black shit eating my character's boobs.
2. there's black shit eating only my character's boobs.

Here look at this:



No more black shit, right? That's Breastacular. Breastacular is a geograft.



I turned breastacular off in the two images above... and you can see where the geograft ends and the torso begins. Now go back to that first image. Look where the blackness stops... right where the breastacular geograft does.

SOP you add the breastacular geograft then use the script that comes with it to copy the skin material from the torso to the geograft. So the skin material on the breasts should be the same material the rest of the torso uses. And yet... it's behaving very differently.

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Spectral rendering and caustics are off. And it's not always like this. In fact, I could probably move the character around a bit in the scene and the issue would go away.... but this keeps happening and I keep having to tinker to make it go away. Any Ideas?

(btw I'm mostly being silly. I'm not actually panicked by this or anything. But it is a genuine issue I'm having.)

UPDATE
So I've done a lot more tinkering with this. Looks like the transparency thing was a red herring. That is a separate issue that's caused by the shell clipping through the graft... which only happens when the base character is hidden. Since i'll never be hiding the base figure but leaving the breastacular graft visible in a scene... it's not an issue I care about. But maybe it's related somehow. Additionally, this means there is no relationship between the shell and the issue... I can even remove the geoshell entirely and the geograft still has the black patches.

I've taken another close look at the breasts in the scene in the screenshots above... I can't see inside the mesh at all. Not even using a spot light source inside the torso. So these black patches are not transparency... they are actually black. I was wrong about that.

Here is some additional screenshots to provide more context...

First we have the exact same character (including the same... currently hidden... hair and clothing), but in a different environment... my "studio lighting" environment I use for character design. As you can see there is no black shit eating the boobs in this one.


This makes it seem like the environment is a factor. That environment being PW Nirvana Space Station. Oddly, removing the space station and everything but the figure from the scene and then replacing the environment settings (hdri, etc) entirely has no effect... as if the black patches get baked into the skin somehow.

And here we have a screenshot of the same everything except the character is in a different part of the same environment as the first two screenshots above. Note that the issue is much less pronounced here. In fact, in previous cases like this I've simply fixed the issue in post.

 

[slitherhence]

Hmm, looking into it further, looks like the geoshell that comes with Breastacular is somehow interacting with the geograft. I thought I had already tested this but... Turns out I had already tested this. It's a red herring, see the updated OP.

The irritating thing is that this only just became an issue in the last few days. But I've been using these for weeks now.

 

[Spin256]

Maybe a UV issue. Looks like a face between the boobs which suggests the entire skin map is being applied to the Breastacular part.

 

[slitherhence]

I've updated the OP with more info.

Maybe a UV issue. Looks like a face between the boobs which suggests the entire skin map is being applied to the Breastacular part.

Thanks for the suggestion. Unfortunately, I don't think that's the case:

And in the first image in the OP you can see the nipple/areola from the base skin on the breastacular graft. Then there's the first image in the update of the OP where there is no issue at all.

 

[probably_dave]

Hi slitherhence, how far away is the character from the centre of the scene (position 0)? I've had similar issue with odd geography cut out (most famously the eyes), when the character is very far from the centre. You might be experiencing something similar. If so, it's just a case of grouping your entire scene into a group and moving it so it's closer to the centre. Might be a red herring of course.

 

[slitherhence]

Hi slitherhence, how far away is the character from the centre of the scene (position 0)? I've had similar issue with odd geography cut out (most famously the eyes), when the character is very far from the centre. You might be experiencing something similar. If so, it's just a case of grouping your entire scene into a group and moving it so it's closer to the centre. Might be a red herring of course.

Interesting idea, lemme try that...

[several minutes and some tinkering later...]

So I made a note of the character's coords before grouping everything, grouped everything in the scene together, then subtracted the old character coords (-4875.027, 7.0, 1580.581) from the new group's coords (0.0, 0.0, 0.0) and set that as the new group's coords (4875.027, -7.0, -1580.581). This places the character model directly in the center of the scene (same as it usually is in my "studio" scene).



And the result (drum roll please...)?




Thank you probably_dave. I never would have guessed. Come to think of it, even having this character a few hundred centimeters from 0, 0, 0 was enough to occasional cause some black patches to appear in the eyes... just as you mentioned. Well, the more you know...

Thank you again. Exactly the kind of deeper knowledge I needed access to in order to solve this.

 

[Blackthunder_vn]

Hello,

had an issue with the eyes in daz, The Problem was the Char was to far from the middle away.

Searched for an script to set the activated Object as middle, all cams positioned as it is.

Result was no Black eyes more.

If you need it text me. Evtl. it is the help for your problem.

Greetings Blackthunder