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Unwanted seams while using displacement map.

ZBrush Usage Questions
#9

The last stable official release of Vray was 1.09.03r I believe, so you should probably think about updating. :slight_smile:

Edit: Not 100% sure about fix seams, UV adjustment, check UV’s, and smooth UV’s, so I removed part of this post. Maybe Aurick or Pixolator will comment on this (I’m curious too).

#10

You mean that FIX SEAMS function makes some change to the UV coordinate system rather than the texture bitmap? :eek: I’ll check it later. :smiley:

#11

What are the settings that you used in the Displacement menu before generating the map?

Can you try testing the map with a different renderer? This will determine whether the problem lies with the map or with the renderer or render settings (which is actually the most likely case).

#12

Also, you didn’t mention in your clarification whether or not you’re applying any iterations of mesh smoothing to your model at all. This does help sometimes with the exploding mesh problem (like the second image shows). And the first image still definitely looks like some of the problems I’ve encountered with Vray’s 2d mapping method in the past.

#13

To Aurick:

Adaptive is on, SmooothUV is on, and DPResolution is set to 1024. I’ve tried to turn either and both of them off, but nothing changed.

To Zeddicus:

  1. I checked. The FIX SEAM Function just did some trick to the texture instead of the UV coordinate system, according to my test.

  2. Yes, I added a meshsmooth modifier, and the iteration level was set to 1. (I tried 2 or 3. Nothing helpful)

#14

To Aurick:

I exported it again and tried it with both Vray and FinalRender(MTD). Although the image generated by finalrender is worse, but you can see clearly that the seam were always in the same place.

(And BTW, would you pleas tell me where I may put this model temporarily? I think it would be more easy to find out the bug with the file in your hand. Thank You)

The following picuture is generated by FR:

[img]http://www.albumsnaps.com/viewPhoto.php?id=32915[/img]

And the next one, by Vray:

[img]http://www.albumsnaps.com/viewPhoto.php?id=32914[/img]
#15

I notices the same problem ate the UV seams when i apply a displacement map in Zbrush on a model. The problem is not visible in preview mode, until you aply the displacement map.

#16

Can this problem be model-related? This model was exported from 3DSMAX as an .obj file and then imported into Zbrush. But not all the models from Zbrush bear this issue. :qu: :qu: :qu: :qu: :qu:

Is there any thing I shall not miss to get a displacement map that works correctly? (I think I’ve read the reference carefully.)

#17

I have the same matter :mad:
If it´s impossible to fix ,how can I to avoid it?
Vray 1.5 …?

#18

Although you haven’t shown a wireframe, it looks like the seams are probably due to triangles or diagonal discontinuity.

Displacement maps are very sensitive to changes that may appear at the UV borders!

There are several things that can be done to avoid visible seams. The fastest and easiest is to use a quad-based mesh with AUVTiles (at the default AUV ratio) or GUVTiles mapping.

If the mesh contains triangles, you may want to try the following:

  1. Go to subdivision level 2 (which is 100% quad-based).
  2. Press Tool>Geometry>Del Lower to make this the new subdivision level 1.
  3. If you wish to use a map size other than 1024x1024, create a texture of the size that you would like. ZBrush works best with a power of 2 (256x256, 512x512, 1024x1024, 2048x2048, or 4096x4096).
  4. Set the displacement map size to match the texture size, and create your displacement map.
  5. Export the displacement map and the mesh to the external renderer.

This approach will allow ZBrush’s SmartSeams routines to execute automatically.

#19

Thank you very much Aurick, I´ll check all things you say(I´ve been changing a lot of things those days and I´m a bit confused).

Here is my mesh and especifications.
www.cgshopping.net/chuske/problema2.jpg

Maybe I´ve diagonals discontinuities…

:rolleyes:

#20

Thank you Aurick for your suggestion. I tried it but the problem remained. But thank you all the same. I think I’ll try to find some way out myself, and I’ll post it here whenever I find the answer.

#21

I’m getting almost the same problem except in lightwave and was just going to post to see if anyone knew why it was happening. Check the screenshot below it’s the render in lightwave, i have the problem areas circled.

#22

I just wanted to bump this one up cause it’s happening to me too. It’s funny because I see tons of renders with Vray in Max and none of them have seams. Yet, when I try, it’s really bad. My uneducated guess is that I’m (we’re) doing something wrong at the UV creation stage in ZBrush. I don’t think it has anything to do with VRay because others have shown the same results with other renders (BTW: With LW, the new Normal Displace plugin seems to help).

So, if anyone is able to render ZBrush displacements in VRay, please let us know your ZBush UV settings.

Thanks!

#23

Hi.
I have a similar problem.

I have done the UVs in Maya.
Export the model from Maya into Zbrush.
Then generated the displacement map with Adaptive on, SmooothUV on, and DPResolution set to 2048.
In Maya, I applied the map to the bump channel.
Mental ray for Maya to renderd the model.

I can see many seams especially around the forehead.
Also the surface in Maya is not clean compared to in Zbrush.
How can I fix this?

UV

Zbrush

Mental ray for Maya

#24

your uv is all seperated mill that will definitely cause problems, it’s best to get as close to huge continous sheets as possible, like you are unwrapping the pelt of something

hmm so just a question, are tiles generally incompatible with triangles because I noticed my quad model that looks fine ahead of time once put into a game engine (which automatically triangulates) the seams of the tiling become visible at certain angles - also I notice this is probably because the tiled texture has a definite space between every tile, is there a way to eliminate this maybe?

edit: aha i see the fix seam option perhaps it can help

#25

Thank you for your reply.

AUV mapping solved the problem.

But I want to make UVs in Maya.
Because I don’t want to assign too much pixels to the top of the
head or the back of the neck.

Is there a way to import UV mapped objects from Maya?

About game.
I think that’s because a texture used in game is low resolution.
The pixels around the UV borders become relatively big.
How about increase the Fix Seam Border slider?

#26

that’s possible, I tried some tests with fix seam and whatnot and I still have trouble though, I think tile methods will lose their integrity on triangulated game models so I’m not going to bother anymore, just use my own uvs

“Is there a way to import UV mapped objects from Maya?”

yes, save it as an obj, import it in zbrush and then click tool> poly groups> uv groups and it will use your uv’s

#27

Thanks.
But if I make uvs in Maya, Zbrush gives me seams.
Even though there is enough space between uv borders.

#28

select your mesh in maya.

attributes->add attributes->vray->displacement control