Does someone know why i sometimes have these strange green artifacts, and how i could get rid off?

It's very annoying, it occurs with some of my koz hair (i didn't try all). This render uses HDRI map and GI, perhaps it's about that?

Can't see anything on the attached render, it's too small. Maybe, an area render blow up?

Well, you'll find it funny, but i was unable to reproduce that in bigger size. I mean even with a zoom in, the green areas were smaller again, but always there! It appear only with the antialias pass, and the shape changes with the pov.

I really don't know what happens! I don't know if it's a problem of transparency or something else.

Have you got any idea?

Maybe check the transparency tab in the advanced mat editor, an see if there is any "fading out" happening.

It's very very very annoying!!!

edit:
Perhaps it's about my antialias setting, cause it only appear with the antialias pass when tile rendering active?

It really appears to have to do with transmap. Here, the artifacts are localized around the "cap" of the hair (see the preview picture) where it touches the head. Except for the D3 picture, Each times it occured, it was there or near the eyelaches. So i really think it's a trans problem.

Anybody had the same problem?

Quote - So i really think it's a trans problem.

One thing to try is to connect the transmap to the Specular_Value input and set the Transparency_Falloff to 0.0 (many older MAT poses leave the Falloff at it's default of 0.6).

If that doesn't cure it, you might try adjusting the Shadow Bias on any lights you have castinjg shadows (given that skull cap like parts are usually very close to the surface of the head).

Yep, but the problem occures into Vue6 Esprit, and not Poser. And for this one, i didn't use Poser Shader Tree. So i don't know what i could do. It's nothing i couldn't solve with postwork, but i would like to know what it happened...

Quote - Yep, but the problem occures into Vue6 Esprit, and not Poser. And for this one, i didn't use Poser Shader Tree. So i don't know what i could do. It's nothing i couldn't solve with postwork, but i would like to know what it happened...

Sorry about giving info for the wrong app

Some material settings must get carried over even if you don't use the Poser Shader Tree, so the problem is going to have a similar cause and solution (but in this case I don't know the specifics of the answer, but the transparency / highlight settings will be involved).

Here, no highlight issue because there is no light, only HDRI illumination.

Try increasing the "Quality Boost" of your GI atmo to 1.0.  I sometimes get this problem with small images using GI

I could be wrong here, but I'm sure I've had this in the past but when I turned the AA settings higher the problem was gone. Just a thought.

@stormchaser:
As you can see, my AA settings are already up (perhaps a little too much for my needs, but i saw a difference for the quality of the hair).

Thanks to all for your help. I've been long to answer, but i was on other projects at the same time.