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Displacement map are being created as almost entirely gray

ZBrush Usage Questions
#1

Hi I’ve been using Zbrush for a while now and I keep running into the same problem. After a while all of my Ztools (OBJ’s imported from MAYA or XSI) start producing bad displacements maps. In the beginning my meshes would produce nice low alpa depth ( 1 to 0.25 range) well defined displacement but now they produce almost invisible huge alpha depth (300 to 400) crap

The problem I think occured when I exported the mesh as an obj in at the lowest level SUB-D level to correct some UV issues in XSI. I Imagine I should have have fixed the issue on the original meshes in XSI using the texture that Check UV creates as a guide then reexported as an ob and reimported that instead to correct the overlapping UVs. ( this method was advised in both the Maya and XSI Zrush workflow pdf’s) I really hope there is a way to again get good Displacement out of the meshes ( crevise map and normal maps both work fine ) I have heard so many different theory on starting your work flow for ZBRUSH ( storing a morph target, not storing a morph target.) I’ve been getting good results with both the morph/no morph methods in both XSI and MAYA. I’m really hope my ZTL havent gone corrupt, Thanks for your help.

#2

what are you using for the base…your reimported base mesh or stored mt? if you are reimporting are ya using the level 1 base that has been changed by zbrush or the original? am curious for myself.

#3

I am using the base that has been modified by ZBRUSH, exporting that to XSI to correct the UV’s then reimporting. Is that the wrong procedure?? I could Swap the corrected UVS from the new ZBRUSH mesh to my original base mesh and reimort that. I’ve been told by many people (Zbrush employees even) that you no longer have to use a morph target or cage, and I’ve been getting good results from the Displacement map on my ZBRUSH level 1 mesh in both XSI and Maya. Should I still be using the original mesh because it scemes that with most models the under lying modification to the base mesh are so drastic that the original mesh could not support the changes. Thanks alot for your swift reply

#4

well i am no expert by any means. but I would at least try it as it might help to narrow down the “why” some of your models work and some don’t with displacements.

Since it worked before you exported it out to change uvs…and that seems to be where the problem begins I have to think that something in xsi or maya changes the mesh some how…don’t know if it has to do with smoothing routines or what cuz i just don’t know enuf about this stuff but i find it interesting. do you do any smoothing or ummmm whats the word i am looking for…for uv’s…aw crap I can’t think of the name right now . anyways…what do you do with the model to create your uv’s? perhaps it’s something there?

#5

Also, have you checked to see if you have a stray point anywhere? That would cause the entire map to be skewed, with the details being overpowered by the single point of very high displacement.

#6

Thanks for the advice, I’ve had some stray point but I fixed all of them/. Do you know whats funny, I was getting pretty damn good displacement with my stray point even though the UV shot to the bottom right corner of my UV field. As for my method of UV creation, I unwrap everything in Maya or XSI prior to importing into ZBRUSH. I then detailed the mesh in the Brush and after doing a Check UV I noticed that I had some overlapping UVs, so I followed the procedure in XSI_ZBRUSH pipeline PDF reimported my corrected UV mesh at level 0 and viola my UV troubles were fixed. but Alas that is When my displacement creation troubles began. Stupidly I went ahead and painted for a good Day or two before creating a new displacemnt and finding out I’m getting a grey square. Thanks again, hopefully theres a solution for this problem.

#7

Getting the exact same issue too - it is totally mind boggling because, like you, I had done several models previously with perfect displacement maps generated (from the MD2 plugin) - now the displacement maps are 100% gray.

I just finished trying 10 different variations in my displacement settings and all 10 are gray.

My process involves simply importing a base mesh from Maya then ZBrushing, applying UV map in ZBrush, generate displacement - then back into Maya. But now every displacement is gray…

Any suggestions ??