ZBrushCentral

Multiple Uv sets and or spaces and how to use them?

ZBrush Usage Questions
#1

Hi,

i´m currently experimenting with photorealistic results in an anatomical study.
Since displacement only got me that far, i´m trying to work out a workflow for creating high frequency details as a bum map (like pores and wrinkles).

you can read about my ideas and findings so far here.

Apart from the problems of polycount i mentioned there, i remembered reading about multiple UV sets and spaces.
So i´d love to see, if these could solve my issues…
My questions regarding this:

  1. When do you use multiple UV sets and when do you use multiple UV spaces? Both in zbrush and an external renderer…(for example mental ray).
  2. How could i use them to achieve highly detailed bump maps?
#2

Ok, i think i got it down…5 Minutes more of searchingand i could have saved myself the trouble…

#3

I can easily use multiple maps, but how to you use them in zbrush so it exports all the maps properly without overlapping maps? (Haven’t attempted it yet.)

#4

hm. Haven´t quite got it yet.

I know how to use multiple UV spaces now…BUT.
Since one of the problems is the polycount i need for the level of detail i´m after is my biggest problem, i did the following:

  1. Importer my new UV layout with multiple UV spaces (one for the head, one for the body) into my lvl1 model in zbrush.
  2. Grouped by UV.
  3. Split tools by polygroups.
  4. Divided each subtool 2 more times (lvl 7 now, each up to maximum 10 mill polys)
  5. Started painting my bumpmaps on each of the subtools.

While i´m writing this i´m exporting all the polypainting (wich i´m gonna use to create a bumpmap) from Uv space 1 (all groups that form the body), with “merge maps” enabled.
But since i can´t continuosly paint over several subtools at once, i will have seams between the subtools.
And since it´s gonna be an anatomical study, i can´t really hide those seams with clothing etc.

So i´m back to square one…how to get enough resolution on my subtools to produce a highly detailed bumpmap and how to do this with multiple UV-spaces to get enough resolution on my texture…

#5

If transferring polypaint (aka vertex color) from a very high poly mesh to high resolution bitmaps (where each one has it’s own UV tile beyond 0,1 no less) isn’t enough, then perhaps ZBrush isn’t the right program to meet your needs. The app Mari made by The Foundry is probably something you might want to consider instead, though it is pretty expensive. Autodesk has been touting Mudbox 2013’s handling of large texture datasets as well, though I don’t know much about it. From the sounds of things, Ptex would be the perfect solution to this conundrum (seamless bump/displacement renders and on the fly variable resolution per face).

Edit: This link looks like it might be useful so far as understanding multiple UV tiles go (using two 4k maps instead of one 8k map).

#6

I was afraid of asking if zbrus is the right tool for that…i´d really like to stick to what i got right now, even though zbrush might not be the best tool for the task.
But since i won´t start doing high-end graphics any time soon anyway (most available jobs probably involving creating simple avatars for browser games with pirating unicorns. if i get lucky)…

I just thought of a possible solution:
Go back to HD-Sculpting. Draw bumpmap as polypaint (because i can´t use cavity masking with HD sculpting. Shame!). Since i can´t work with layers just export the different layers manually.
That way i should be able to use a high enough polycount AND transfer it to a multiple UV space map.
Haven´t thought it through yet and haven´t tried it yet, but in theory that should work, even without having to worry about seams and such.

#7

looks like i found a fix for all of my latest threads in one go:

Using HD geometry and multiple UV spaces to paint a high frequency detail bump map.
And using an FS Border set to 1, so i don´t get those annyoing artifacts and distortiosn along my seams i got when it was set to 8…

Apparently sometimes less is more!

This way i can stay in zbrush, as my level of detail won´t go any higher than what i can achieve this way…

Only drawback is, that i can´t use layers with HD geometry, so if i want finder control on my bump map, i´ll have paint layers by hand and go back and forth between compositing them in Photoshop and checking the look in zbrush…