ZBrushCentral

Help me fix a zbrush issue – earn $200. Texture-bump map tiling along UV map seams –

ZBrush Usage Questions
#1

Here’s the problem:

When painting a model using projection master, everything looks great. When I exit out of projection master, you can see a grid effect that appears to be based on the UV map (AUV tiles.) This effect is easy to miss until I load up the bump surface, at which point it is extremely obvious where the geometry is deformed, and invisible where it isn’t. It is especially noticeable where the bump map banks up or down, and is less noticeable where the bump is a flatter plane.

This is all in Zbrush 2. It’s running on a Mac so unfortunately there’s no option to upgrade to 3 yet. I can export to Lightwave 9.2 and see a similar result. The texture only looks good, but the bump/displacement/normal maps all have the grid effect on it. The displacement map looks exceptionally bad.

Here’s what I’ve tried so far:
Texture size is 4096x4096

I have tried both AUV and GUV tiles. I prefer to use AUV.

Currently the AUV ratio is set at 1, and I don’t think it would affect this issue, but I’d be willing to try some different numbers there if anyone thinks it would help.

With AUV tiles, I tried to Fix seams with the FS border being 1, 4, 8, 16, and 32. These all produced the same results (the tile effect shown above).

I also tried to fiddle with the adjU and adjV numbers in increments from .5 to .01 and had no luck there either.

My original thread regarding this is at:

http://www.zbrushcentral.com/zbc/showthread.php?t=48855

I’ve read a few threads with this issue, and none of the solutions suggested in them have worked. Also, every thread seems to have ended without a confirmation of solution by the original poster.

The $200 challenge is, how do I fix this? I will gladly donate $200 to the first person to give me a solution that fixes my problem.

#2

Sorry, I forgot to include an example.

[TILE MESH.jpg]

#3

How many subdivision levels are you using, and did you turn ON SUV in the Geometry subPallette?

EDIT:
What resolution is the file you’re using, and is it a JPG btw?
You might try resampling it up to 4096 x 4096 in PS and saving it out as a PSD file and then re-importing.

Upload the texture image you’re using if possible :slight_smile: I’ll check it out for you

#4

What’s your poly count and have you tried increasing it before generating the map?

#5

Subdivision levels are up to 5. I have tried with or without SUV with similar results. The texture resolution is up to 4096x4096. I don’t know what the texture file type is when it is created, but I do export it as a PSD. I’ll try exporting and re-importing in a bit.

#6

The poly count is about 7600 before any subdivision. I can try bumping it up a level, deleting the lower and painting on that, but unfortunately that’s not an effective solution for animation, which is what is going to happen when I get it back into Lightwave.

#7

Addition:
I should also mention that this has something to do with the interaction between texture and UV, especially where it applies to deforming the object. Usually I apply the UV first, but I’ve tried to paint on objects with no UVs and they work fine. Once I apply the UV, the issues appear.

#8

I don’t know what the texture file type is when it is created
It matters not :wink:
If you simply export the texture you have; upload it so it can be analyzed, then a more thorough conclusion might be resolved :slight_smile:

It’s always possible that your vertices might be flush with each other, yet not merged accuratly from some other app. … but it DOES seem to me that your initial bitmap is insufficient in its resampling (it appears bilinear rather than bicubic)
The issue is not one of UVs :slight_smile:

C.

#9

Did you try subdividing? Stand-in.

#10

always manualy unwrap your model because the auto unwrap feature of zbrush disects the polygones witch is nice and bad.

the bad thing is is that any sort of texture filtering will brake the texture.
any sort of subdivision will brake your model 2.

#11

ever solved?

you never say you create the 4096x4096 texture first or not before selecting auv or guv…which is necessary for them to work well with your chosen texture size.