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woadiestyol
10-31-2009, 12:37 AM
Hey All,

Just wrote up my first tutorial on a Zbrush/Maya workflow for creating blendshapes with corrective displacement maps. I also just noticed creatingJunk's post on his facial setup, which he seemed to accomplish the same way - so hopefully one or the other will be helpful.

Here's the link:

http://www.canyourigit.com/?p=20

I'm in a website re-design, so sorry about the mess on the site, but hopefully the tutorial displays correctly.

If anyone has any questions or feedback, I'd love to hear them since this is the first one of these I've tried.

Cheers!

-JP

archanex
10-31-2009, 08:43 PM
Thanks for the tutorial man! Looks like a very useful approach in certain situations. It seems like using this approach would lead to very long render times due to the amount of subdivisions required at render time (especially if paired with a SSS skin shader for example) How bad were your render times on the pumpkin guy?

anoopak
11-01-2009, 08:55 AM
Thanks for the tutorial.The output can be pushed to better extends with this approach.Thanks again

woadiestyol
11-02-2009, 11:47 PM
Hey guys,

Glad you like it! As for render times, what I've found is that when I do individual test renders it can take a bit of time just because Mental Ray has to load all the 32-bit displacement maps into memory (and they tend to be big files), but once the rendering started, it was pretty fast. My machine is a quad-core 2.4 ghz with 8 gigs of ram, so it's not too shabby (but also not too state-of-the-art); when I had an SSS shader on the head, a 720p frame took about 2 minutes to render with a couple area lights involved - not too bad. That being said, doing test renders is quite annoying because it takes a while for the thing to start up a render while it loads all those big maps from the disk. My solution was to have a second displacement node that I just had my base displacement map on, and i just leave this connected to my shader while testing shaders and lighting.

I think the key is not to try and use displacement maps to get 100% of your bump action, because then you will end up subdividing a ton. In my scene, my pumpkin head Ztool has 6-levels of resolution, so I got my displacement maps from level 1 but also stepped up to level 3 or 4 and rendered a normal map to get the high-frequency detail on the "base" sculpt. I don't need to get differenct normal maps because the high-frequency detail doesn't change shape, so I just grab one off my base sculpt and slap it on the material (does that make sense?). Then I set my subdivision approx node to subdivide just enough times to get a good silhouette. On my pumpkin I think i set it at 2 or 3.

Thanks for the feedback so far - I'll try and incorporate some of it into the tutorial at some point. If you guys notice anything that I went into too much or too little detail on, feel free to let me know and I'll make the updates.:)

Cheers!

JP

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