VRay and ZBrush - losing fine detail in disp map

[Morbid Angel]

the artifacts are some one known to mudbox. I recommend getting latest service pack, but besides that you can do an auto search distance and then use half of that value, minimizing search distance will reduce the black dots on the displacement map.

[HenrikBC]

I will look into the SP issue and try the search distance / half trick. Only when I made the last displacement map, I lowered it to way less than half of what Mudbox suggested. Perhaps another reason to update SP?

Got my modeller guy to export new maps from ZBrush - made to resemble the ones I got from Mudbox more closely.

http://henrikbclausen.com/kyklop_16.jpg
http://henrikbclausen.com/kyklop_17.jpg

It's a lot better than the earliest ZB results but still a world apart from my Mudbox map export. And the silhouette of the character is altered altogether - not just from displacement height settings that might be a bit off, but the form altogether. And there's the sharp edges that look like remnants from the low poly cage. I just can't believe that it's impossible to do this right directly from ZBrush... :I

[Morbid Angel]

well that could be something else. In zbrush and max if you are smoothing the model the uv's are not smoothing the same. You have to ensure that the uv's smooth correctly in both programs to get correct result.

[HenrikBC]

He got some help from a Bioware guy - but you were right on the money, Morbid. Maybe I should just get you onboard the project as chief displacement problem-solver.

He fixed the UV smoothing in ZBrush and then exported again:

http://henrikbclausen.com/kyklop_20.jpg
http://henrikbclausen.com/kyklop_21.jpg

Now we're starting to get somewhere!

[Morbid Angel]

glad I could help
this uv issue is really bad across different 3d apps too. In maya for example there is two ways you can smooth the uvs and none of them match max, where in max there is no option it just smoothes the uv's but retains uv border its totally messy and undefined.

[HenrikBC]

Yes, I read a tutorial/wishlist on Neils Blevins page about the UVs citing (just for max) irritations and issues over the smoothing.

Anyway, I'm glad we finally got it working. Hopefully it will go a lot smoother with the next characters.

Next up is testing different displacement maps for facial wrinkles hooked up to a facial rig. Any pre-emptive suggestions would be greatly appreciated.

[Morbid Angel]

only suggestion is: good luck !

[Mikokariadis]

"He fixed the UV smoothing in ZBrush and then exported again:"

Could you please elaborate a bit on that. Is there a Zbrush UV smooth value somewhere?

[Morbid Angel]

yes right near divide button there is a button called suv which stands for smooth uv. You must however smooth the uvs before subdividing the model otherwise it will have no effect.

[Mikokariadis]

Thanks for the clear up Morbid Angel. Precious info.

[HenrikBC]

only suggestion is: good luck !

Thanks - I'll keep you posted on how that turns out...

Miko: My modeller friend posted a bit of a make-shift tutorial in his CGTalk thread if you need more info: http://forums.cgsociety.org/showthre...35#post6276435

[Mikokariadis]

Thanks for the link HenrikBC.
You guys helped a ton already just bringing this up and now I see some mistakes in my processes that can be corrected.

[stevesideas]

Did you know you can use the decimator plugin with the new zbrush and retain high detail without the high poly count...apparently...ive yet to try it out..

[HenrikBC]

Miko: Glad to hear it!

Steve: I just checked it out on pixologic's site - looks good, but only seems suitable for static geometry that you wouldn't need to displace while deforming it (unlike characters). But could be very cool for high detail asteroids, rubble, etc. to retain detail without spending the same amount of polys.

[Mikokariadis]

Decimator works great for CNC work. Those folks at pixo really cover all the bases with STL data paths.