I have the "official fix instructions" from digitalbabes2, but they simply say "Turn Texture Filtering On." P7 apparently does not have Texture Filtering; at least I can't find it on the Render Settings. (Is it just me, or does it seem like one of the "big improvements" in P7 was to hose any third party fixes to P6?)

What really puzzles me is that the "black chunks" problem in Koz hair is fixed in the P6 Koz Hair for Jessi, but the material settings are identical to the ones that don't work for Koz hair from digitalbabes2. To whit: Here is a render of Posette w/Koz hair ( I didn't bother to position it) and Deidre (V2, I think) with the same hair but pulled from P6/Koz/Jessi. Obviously, the difference isn't the render settings, 'cause there they are: same render. If there is a difference in the Material settings, I can't see it.

BTW: It looks like Render's "Texture Filtering" has become a Material setting called Filtering that can be adjusted to "Quality," "Fast," or "None." I assume "Quality" is "On," but in any case the hair materials are both set to "Quality."

Note: I just tried copying the Material settings from Deirdre to Posette, and the result was the same. So the difference is not in the Mats.

M

The black chunks are reversed normals in the mesh.  Try checking normals forward in the materials settings.  This sometimes fixes the problem.  An older way I've sometimes used is to plug a simple color node set to white into the displacement channel.  

In P7, texture filtering is now on the materials settings for every material.  It's default is Quality.  

I don't know if anyone else has any ideas.

Quote - The black chunks are reversed normals in the mesh.  Try checking normals forward in the materials settings.  This sometimes fixes the problem. 

"Sometimes" as in it randomly might or might not. Sigh. This is where I started, by discovering that  Normals_Forward didn't fix it. I was reading the "black blocks" discussion elsewhere and tried the recommended fix. It did not work.

However, while I was waiting for an answer, I read the HR2's, where I found three differences that might have mattered but didn't. Then I checked Normals_Forward again, and this time, it fixed it. Same scene, same figures, but I've swapped out the "broken" hair a half dozen times, and suddenly the fix works. Not only that but I replaced Deirdre's hair with proper MW Short Hair, and it was broken until I checked Normals_Forward.

Apparently the Koz hair in P6 and P7 has the normals problem fixed in some way not accessible to mere mortals. It does not come in with Normals_Forward checked.

Now if I can just locate my P6 installer....
M

Make a note of where the problem areas are, and reverse their normals in a modeling application, and export the fixed mesh as a .obj file. If you don't have one I believe wings is free. I hope this helps.

Had the same problem.  Fixed it by pluggin in the texture map to the displacement plug and setting it to .016666.  I also added a white specular highlight to the hair and of course used the firefly renderer with displacement maps on.  At least that's what worked for me. 

Hope this helps.

Sincerely
~ Boni ~

Plug in to displacement rings a bell. Thanks,
M

texfiltering defaults to "quality" in P7. svdl wrote a script that turns it off for all materials. without that script, it's a RPITA to turn 'em all off, but it's usually a good idea to turn 'em all off.