Zbrush -> Maya -> Turtle Tutorial

[Jacob]

Here is a quick tutorial of how to succeed in rendering ZBrush displacement in Turtle for Maya. I have also attached a pdf with more details of the different steps.

This tutorial assumes that the model, the texture mapping and the displacement texture are already generated. For details about these steps, please refer to Pixologic's tutorials and documentation. The values used below are the ones I used for the GUVTiles sword test file.


The Quick Guide

1. Start Maya with Turtle loaded from start


2. Import the .obj file and enable Turtle -> Render as subdivision surface under the shape node of the mesh. Set the subdivision depth to 4.

3. Assign a new material to the mesh and assign an ilrDisplace shader to this material.


4. Load the texture into the shader. Enable Flip Y, set displacement offset to 0.5 and the scale to an appropriate value (10 in this case).


5. Use the preview mode and a small resolution and render. If needed, adjust the displacement scale to get the desired look of the sword.


6. When satisfied, use a higher sample setting and render the final image.




In the image above, I have added some HDRI lighting too.

I hope this is helpful. Please tell me if anything is unclear.

Jacob

[sadicus]

Thamks for the steps!
Have you used TURTLE with a model you have created?

i also get good results with the provided ZB2 models, but any of the models i create, don't look so good!

"scale to an appropriate value (10 in this case). "

is setting the scale just a trial and error?

I know in ZB2 prefs there is a Uniform Scale, but on Exporting an .obj there is also a scale feature. How does the Export scale = Maya units?

i usualy leave mine at 1, but maybe thats why my models look crappy in Maya!

Thanks!

[Jacob]

Hello.

Yes, I have successfully used Turtle with numerous models that I have created myself, and models I have got from other ZBrush users.

I personally set the displacement scale by trial and error once I'm rendering. There is quite some parameters in ZBrush to control the scale, so I have not yet found a good answer to this. Let me know if you find a good solution.

Some comments.

- Choose a UV scheme that does not cut up the UVs too much. A more continous UV scheme is less prone to generate cracks and holes, when ray tracing the model. A UV scheme where each base mesh polygon is cut up and spread out more or less randomly in UV space is the worst possible case.

- Use smoothUVs when generating the map in ZBrush, check the [mrg] uv's button when exporting the .obj file and make sure the [grp] button is unchecked. Subgroups does not contain the connectivity needed to subdivide the basemesh.

- I have experimented with both the "cage" and "MorpthTarget" as base meshes, and both seems to work well.

I hope this helps!

Jacob

[sadicus]

"- Choose a UV scheme that does not cut up the UVs too much."

.... Like GUV tiles? (that is what i've been useing in zbrush)

Thanks for the advice!

Also, i think i'm expecting to much from DispMaps. Like Displacing teeth, instead of actualy modeling the teeth. Disp Maps should be used for more subtle detail like veins, or small bumps, not to create horns or teeth that stick far out of the body, but instead be used as small displacement on such forms....?

What would be the correct way to get the "fin" effect as in this fish example?
http://pixologic.com/zbrush/media_links/movies.html

what subd level would you export the Cage or Morph in order to get the Fins to properly displace for animation in Maya6?

[Sleepwalker]

Hi there, I've been betatesting Turtle for a day now and I can't seem to get rid of the tiny black dots on some parts of my models, even if I lower the shadowmap zcutoff ? Have you encoutered this problem on any of your own model Jacob? Displacement is quite straightforward, thx to your tut BTW

[sadicus]

I also get the black dots. zcut seems to make little difference.

[Dan B]

Sleepwalker and sadicus - try setting the render quality options as high as they will go and use a .1 or lower setting on the contrast ratio - this is all under the turtle Globals. Also try using the multi-pixel flitering - and using Turtle shadow maps seems to help as well. Usually when I get all those errors I scale the object up several times - the larger it is in World Space the more accurate the displacement tends to be. ( .1 was not the correct setting until I scaled up the object ) I hope this helps - those little black dots are annoying! I used Turtle for this project ....

http://www.zbrushcentral.com/zbc/showthread.php?t=021075

and once I got the right settings all the little errors disappeared.

Jacob and the guys at Turtle are always helpful and want to make turtle the best renderer out there, so don't hesitate to send them the file you are having problems with - I've done it many times before

[sadicus]

I have no idea why i always work in the default Maya Grid! Doh! like it represents the edge of the world. Maya is not Flat!
Anyway, Yes The TURTLE team is great, but i know it's usualy something ignorant on my part as far as settings go.

Thanks for the advice!

[Sleepwalker]

I'm no maya expert, when you mean get the highest are you talking about sampling ? I stayed within Maya grid, switch off emit photons in the light tab, turn off LOD and now I can get general or closeup shots without problem.
Sadicus, zcutoff didn't make any change for me how did you get rid of those dots so easily :-)
THX guys
ps: Dan B and Sadicus in case you need closeup skin shots I uploaded a hires .tiff on this link:
http://www.zbrushcentral.com/zbc/sho...t=22217&page=1 (bottom of the page).

[maiomika]

hello, i have been trying to use turtle in maya to bake maps but am very new at it and find that there website is just too complex to understand for a beginner like me. i was really happy when i found your post on using maya turtle, but when i tried the link it just wouldnt work for me. does anyone know of anywhere else you can find a turtle bakeing tutorial, or undertands enough about how to set up baking and use it in maya to explain how you do it step by step, but with a bit more information then what was giving on the first post of this posting?

[redsunlee]

Thanks for your sharing. Thanks for sharing this useful information. It's great.


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