IRAY Hair Translucency
marble
Posts: 7,500
I've noticed a recent problem when rendering some hair - particularly OOT products. The two renders below illustrate the problem which turns out to be fixed by setting Translucency Weight to zero. The thing is that I have renders from a few weeks ago which don't show this problem yet, if I load the scene now and render it, the Translucency needs correcting. So I can only assume that something in DAZ Studio 4.15 (IRay?) has changed. The two renders are of the same hair but with Translucency Weight set to zero on the second render.
Everyday Updo.png
800 x 800 - 776K
Everyday Updo NT.png
800 x 800 - 603K
Post edited by marble on
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I tried and saw the same problem with other OOT hairs - Marlene Hair and Various Age Bob Hair. The effect is introduced when I go the the Materials and click the OOT supplied "Apply This First" setting.
This happens for me with just a base G8F and the hair in the scene. No volumetrics (I don't think that I've ever used volumetrics), no billboards. It seems to be only OOT hair and only some of them but it is definitely zeroing the Translucency Weight setting that removes the problem. If TW is set to anything but zero the problem appears and it is not gradual - it is constant at any weight setting.
Instead of setting Translucency Weight to 0, I change every hair surface (except the cap) that use 1.0 cutout opacity to 0.99. Should fix it (I read that solution somewhere but don't remember where).
Thank you - that worked like a charm. :)
Thanks for this. I was having the same problem with the Karla hair in 4.15.
daz: 4.15.0.2
Setting the cutout opacity to .99 fixed the problem.
Anyone know when this will be fixed?
Setting the cutout opacity to any value below 1 actually sets the "Thin Walled - ON" parameter.
This means disabling the following parameters: Transmitted Measurement Distance / Transmitted Color / and SSS parameters.
In theory, this makes the hair worse. At least not the way the hair creator intended it to be.
This is a workaroud until nVidia is able to fix Iray and we get a DS update with the fixed version, not a denial that there is a real issue.
I've found using a gradient map on cutout, and setting it to about .8 works pretty good at softening the ends of dforce hair.
Gradient used attached below.