Lines on forehead possible solution?

gripper4hire

I think I might have found something to check on for those annoying black "tear" lines on the forehead (caused by skull caps and such) in the iray render. I did a forum search and havn't seen any posting proposing this. Most posts mention about adjusting skull caps, or repositioning the character to the world-center.

However, first, try selecting ALL the materials (and I mean ALL) in the scene... this can be a challenge if you have a lot of objects. And then simply apply the "Iray Uber Base" shader to it to make sure all surfaces are using iray.

I have now done this several times over the past few weeks - without having to adjust skull caps, or reposition characters to the center of the world (0,0), and it has worked every time to get rid of those stupid tearing lines. When I thought it didn't work, I looked further into the scene and found something - a small Genesis 3 peice of jewlery or a prop from Poser - that was not using iray materials, and when I applied the Iray Uber Shader to all the material zones on the item, the tearing goes away. This is immediately seen when using the NVIDIA Iray view in the viewport... tear on forehead, apply Uber Shader, the viewport turns grey for a second as it re-renders, and voila, forehead is now clean and everything looks good.

I am wondering if the iray rederer is creating these tears when it trying to resolve light paths for 3Delight (i.e. non-iray) content?

Hope this info might be useful, for an eventual fix from DAZ, as I never noticed this issue in older versions of DAZ Studio.

Cheers,

g4h

DMax

Hmmm that tip sounds delicious! I will definitely give it a shot when I next have the ugly scalp links (which is rather often!). Thank you :)
In my other thread, the suggestion of changing the instancing optimization to "speed" helped instantly as well... not sure if it's only for that particular case.
https://www.daz3d.com/forums/discussion/411941/adding-hair-produces-unsightly-scars-on-forehead#latest

fastbike1

Studio / Iray should be automaically applying the Uber Shader to non Iray materials. However, that may stil be less than optimal. The line will go away with a small expansion of the cap. Won't need to use uber for everything unles you havven't been using Iray Hair.

Leana

fastbike1 said:

Studio / Iray should be automaically applying the Uber Shader to non Iray materials.

Not exactly. DS converts materials at render time, it doesn't automatically change the surface settings to apply Iray Uber shader. End result should be the same though.

kenshaw011267

It's way easier to adjust the skullcap

Sevrin

kenshaw011267 said:

It's way easier to adjust the skullcap

I'll say.

fastbike1 said:

Studio / Iray should be automaically applying the Uber Shader to non Iray materials. However, that may stil be less than optimal. The line will go away with a small expansion of the cap. Won't need to use uber for everything unles you havven't been using Iray Hair.

Not everyone renders using Iray.