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Rendering Zbrush Displacement in Maya2008 - Separating Faces in Render

ZBrush Usage Questions
#1

Hope this is not too stupid a question, but I seem to be stuck for the last few days with this.

I have been searching the Forum/Google on and off all day, and I can’t find a solution. I have been trying all sorts of different settings in zbrush and maya and still I’m getting this problem.

In the pic attached,

Displaceboom.jpg
Displaceboom.jpg1335×504 23.4 KB

  1. is the base mesh in Maya ( brought from Zbrush )

  2. is the detailed mesh in Zbrush ( with the UVs done in Headus then imported back into SubD1 )

  3. is what I’m getting when I try render the displacement map in Maya2008. All my faces appear detached and floating. I can see some of my details very faintly on the floating faces and it appears to be lining up with the UV map correctly.

The weird thing is, if I take a Maya poly sphere and drop the Shader onto it, of course the detail will be scrambled because the UV layout is different, but you can see it displacing the correct height, without seperating faces in any way.

I can gladly give any settings or details, as I have my scene file handy, but I thought perhaps someone would know exactly what I’m doing wrong just by seeing pic 3).

I did turn on set the preference in Maya " Use Maya Style Alpha Detection On File Textures". I set the displacement alpha gain/offset as shown on the forum ( 2.2 and -1.1 ). The last setting I used was DE-LBEK-EAEAEA-D32 as the code for the disp map ( thought I also tried with Auto and R32 variations). I tried turning off “feature displacement” in maya but on or off I get the same result. And I tried a few scripts, but I guess they were not for my problem because they didn’t help.

Any help would be greatly appreciated !

#2

How did you setup the UV’s?

If you use AUV tiles… if you do a UV >tex map and take a look at it… 20 to 1 you will have large open spaces between your polygons. if you don’t… when you bring it into maya… give the whole thing a quick merge UV’s… they may be overlapping but not actually sewen together.

#3

Lusankya,

Thanks so much for responding.

How did you setup the UV’s?

The first time, I used AUV. I did see the gaps in the UV tiles, and didn’t know how to fix that in Zbrush, so I took the base model into HeadusUV instead and did more of a pelt-like layout. So, in that kind of layout there are going to be spaces between UV shells. But when I checked out my UV editor in maya, the faces were most certainly seperated when trying to select my Shells. I did a merge UV like you suggested ( though on my Headus layout ), and it totally made the pieces sewn together where they should be.

The new render still shows exactly the same problem though, unfortunately.

Like I said, when I apply the same workflow to something organic, that I will apply a Mental Ray Subdivision Approx to as well as a Displacement map, it doesn’t split apart. It’s only happening to me now that I want to use sharp edged flat faced geometry for displacements. I tried dropping the map onto a regular Poly Cube in maya, and all the 6 faces of the cube seem to seperate as well.

What is the code you would normally use for MultiDisp3 in Zbrush ? At the moment I have it set to the R32 code that people around the forum seem to like.

I am gonna try more to fix it today. Hopefully my keyboard will survive me this time ( hulk smash ).

Thanks for the tips.

#4

Having just successfully gotten displacements working myself… and not having done hard edged objects… I cannot assist further…

As for my MultiDisp settings… hmm actually I don’t use it. I tried the tutorials and workarounds I’ve found here and in even in the Scott Spencer book (random plug) but never got it working… finally i went back to my school and sat down (for 3 hours) with someone that works with zbrush and maya at midway and he didn’t even bother to use MD3… got our settings correct which were different then any of the tutorials or books, such as the 2.2/-1 alpha gain/offset… the use of the displacement approximation and MD3, exprted as a tiff using normal zb3 export and poof my displacements finally worked and I now know how to get them working… organic ones at least…

#5

any chance you could lay out your workflow here ?

#6

ZBRUSH
Export model w/o groups
Create displacement… turn on adaptive, and Mod… smooth UV optional on occasion. Set map size to desired… I use 3072
Flip alpha along the V… export using regular zbrush export as a tif
use convert batch file to change tif to map

Maya2008
Import OBJ
Turn off feature displacement
Delete OBJ texture
Create blinn or Phong
Add displacement node… add map file
Change color balance of file node
(this is where everyone says use 2.2 and -1)
try this instead in the file offset use the expression
file1.alphaOffset = file1.alphaGain /2 * (-1);
change the file1 to whatever the name ends up being
Select model and open mentalray zpproximation… add subdivision approx… change to spatial
Min is 1
Max is up 4 or 5 depending on system (start with 2)
length is .1 or less… the longer the length the shorter the render time (not confirmed)
set mental ray settings to draft for speedy results.
Click render

It appears the alpha gain and the max subdivisions settings are the 2 that determine how strong the displacement is.

Not 100% foolproof… its not totally working on another model I have that was imported into zbrush… but the above worked perfectly for a zsphere based creation.

#7

Thanks !!

I really appreciate you taking the time to lay out your workflow.

I will try it out. The main difference seems to be the way you create the Displacement Map in Zbrush, so I am going to definitely try this out today. Will write back with results.

Again, thanks.

#8

Survey Says?

#9

i m also having the same prob
and when i used the displcement map in the bump map node instead of dispalcement node in maya , the problem goes.
i don’t know how to use it with displacement node