ZBrush -> Messiah test

[lmilton]

There are known issues with Zbrush output, but your cracks are quite extreme. Did you MetaNURBS the model? Also, what's your displacement subdiv level?

-lyle

[Swissphil]

Lyle,

It seems, this is not a Messiah problem. I applyed the displacement map inside ZBrush to the LowRes model and it shows the same artifact. Obviously it happens when I create the displacement map inside ZBrush.

But thanks for your help anyway :)

[AlexK]

I start to get the impression that ZBrush isn't so great at all. I mean nearly every post I read is about crack issues. Are there any positive comments about ZBrush?

[Swissphil]

I think if you want to bring in a lowres model into ZBrush for detailing it might be a good idea to have a prober layed out UV Map. I created mine inside ZBrush and therefore had no control over the seams.
The huge crack I get at the wings base is obviously a error in the map that lays on such a seam. I'll do more tests, with other models, don't worry :)

[kobi1kobi]

Hi

I've had some problems rendering the sword scene too (MAYA+Turtle) but the nice people in turtle told me to use the higher subd level model and the appropriate mesh.
Sometimes it's not possible to use the lowest level to get good displacement, but even using 1 level higher - lets say 5k poly instead of 1k poly, is better then 3m poly model.
So, export a higher subd level obj file, get the appropriate displacement map, and experiment with the mapping options.
Biggest problem - not all render engines think alike - what works with renderman won't work with MR and won't work with messiah.

thats my 2c, and I hope it will help you.

kobi

[Swissphil]

Kobi.

I'll try it with the higher Suvdiv level Model. but I think render times will increase significantly...

[kobi1kobi]

I don't think so, but let me know.
As far as I know (and I'm talking from MAYA render point of view) the displacements are rendered when the object is rendered as a subd model. I know know if messsiah renders subd directly (like prman) or it converts it to lots and lots of polygons at render time.
In the second case, you might get a higher render time, but not very much, and the quality should be better.
If it renders subd directly, then it won't matter.

[Swissphil]

Kobi

Rendertime increased from less than a minute to about 5 minutes, but the result was the same. Anyway, as the error has nothing to do with Messiah, this isn't the way anyway. I played with the settings inside ZBrush and got this result:


http://homepage.mac.com/philippweimer/MessiahDragonCol.jpg


Definitly an improvement but not yet perfect :))

[WesComan]

I've just been playing with some of the ZBrush values today to try and get rid of the displacement cracks and have had pretty good success tweaking the Texture->AdjustU and AdjustV setings. On a 2048 texture I started methodically adjusting them by 0.5 pixels to get the best I could, and then by 0.25, 0.1, 0.05 and then fine tweaking of 0.01. It's pretty boring...adjust the values, export the object, reload the messiah scene, render -> adjust the values, export, reload, render etc... I pretty much got the cracks down to a negligible degree (they almost antialias out), but couldn't get rid of them completely.

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