Rendering ZBrush Displacement-Maps In External Renderers (May 9th: 2nd file added)

[Jhotun]

Fingerman, could you post your settings for the material and for mental ray displacement? I'm dying for getting those results...

[vivien]

here is my test....

i am quite satisfied since it took me ages to figure out how to do it....but thanks to my teacher gattomanzo, my boy drummer and a fellow italian zbrush user smilegrafix (grazie a tutti!), the dirty work was finally done.

i converted the texture in photoshop to rgb 16 bit, and although some say that 16 bit doesn't work, to me it seems fine.
here is a picture of the rendering and my render tree. i increased my alpha to 4,834 (from a starting value of 0,834).
for the rest on my change range i put 1, 0, -1, 1.
if anyone who uses xsi needs more explainations i'd be glad to help

[macaco]

mangriff vbmenu_register("postmenu_193992", true); thanks for your settings! the trick was to turn off displacement!! If not max also crashes to me!

Since I haven't seen many brazil renders here is mine with a skin shader and any map used in the material.





It would be nice if people had a resume of the best way to render displacements in each software Just an idea

Bye!!

[macaco]

UOPS! I forgot! Redered in 27 seconds P IV, 1GB RAM, ati radeon 9600 pro
bye!

[obskure]

No images to post. Thanks for this thread Pixolator, it has really helped me understand displacement maps.

For those of you using 3ds Max I found that with a standard Displace modifier and a Turbo Smooth at 4 render iterations the Scanline renderer rendered the fastest with 11 secs, Mental Ray with 22 secs and Vray with 27 secs (vray took longer than 27 secs with a Turbo Smooth at 2 and a Vray Displacement Mod achieving a slightly lower quality render, Vray mod uses adaptive Subs achieving more detail but not completely smoothing the basic mesh). All renderers were default settings at 640x480 on an athlon 2500 with 1gb ram.

Zbrush has accelerated my 3d development at least 10x

[obskure]

1:11sec to render in Mental Ray with Skin shader and one light. Mesh with Turbo Smooth 4 render iterations and Displace mod.

[tisho]

Rendered with VRay and PPT, 5000 subdivs, 2 raytraced lights, GI.

[url="http://www.vrayrender.com/stuff/tisho/head.jpg"][/url]

The small grips on the shoulders can be fixed if subdivs are increased to 10000 and leave it to calculate some more minutes. Here is a test /head45/ where I left it while I was on lunch.

[ATT=9709]head45.jpg[/ATT]

[temito]

3dsmax7

[TigerZ]

I just tried it in Max with MR, and altough its slow and uber memory expensive, the results are very cool, I just wished the MR displacement had an offset parameter...

[Numse]

Needed to test how I shall configure exported displacement maps from Zbrush, this is the resault.

Vray for render

[Jason Belec]

Here is a test in Pixie (OpenSource - REYES renderer, based on the Renderman API).

'Arm' by Edwin Nortey, 'Head' by Pixolator of course.

Oh yeah... 450MHz G4 Cube - rendered in 20 seconds.

[JackMcRip]

I've been heard somebody have problems with C4D R9 and this File.
You must only import the Obj-File and add the displacement Chanal to the Material.
In the displacementchanal load the .tif Displacement textur.
Sub = 4
Strange = 0.7
Rounding

In the objectmanager flip the texturtag vertical.

Then render


Here is the File to check the settings:
http://www.total3d.de/pub/temp/C4D-Disptest.zip (4,1MB)

[sascha]

Rendered with Gelato 1.2 R2 on a 2 GHz Athlon XP / GeForce FX 5600 in 14 sec.

[YC Chen]

max 7, MR SSS fast skin mat + displace


3:17 on Athlon (don't know which) 2.0 GHz

I used the settings posted by Zeddicus on page 6 (on max 6 + MR).

Important things I had to learn to make it work:

Turbosmooth iteration: 1, no additional render iteration (this+MR displacement overstrain max = many hours of headache for stupid me).

A light behind the ear and scale conversion (under advanced options) = 0.1 should show SSS, though it's still subtle. But it works. I have to play more with SSS parameters...

Blur offset did matter and was at 0.01. At 0, I had banding, which is really apparent if the base mesh is not smoothed.

[hotsalsaept]

The concept of displacement mapping is not new, but the significant interest in it certainly is. Since the use of displacement maps is not yet a standard feature in all renderers, a certain degree of experimentation is required in order to achieve optimal results.

This thread is intended to be a 'one-stop shop' containing posts by ZBC members who have successfully rendered ZBrush-generated displacements maps in one (or more) external renderers.


Achieving optimal results in external renderers requires you to...

1. Generate the displacement map correctly.
2. Experiment and find the best render-settings in the external renderer.

To simplify the process of finding the optimal workflow, I'm including a sample low-res head mesh with its calculated Z2 displacement map (step 1). This will allow you to concentrate your efforts on getting the best results out of the external renderer (step 2).

The following is the test mesh which was created, detailed and then rendered in ZBrush with, and without, the displacement-map...




Use the link below to download a zip archive which contains 2 files: the low-resolution mesh (OBJ format) and the displacement-map (TIF format).

Click here to download the ZIP archive

Note 1: The displacement-map may need to be flipped vertically for correct UV mapping.
Note 2: The displacement-gain in ZBrush was set to 0.834; you may need to factor this value to achieve similar displacement amount in the external renderer.

Test these files in the renderer that you're using. If you have achieved successful results (similar to the above image, in any color) you're invited to post your findings in this thread, so others can benefit from them.




To keep this thread as informative as possible, please don't post unsuccessful results here. If you have encountered difficulties or have questions regarding this thread, please post them in the Q&T forum.

As time progresses, the usage of displacement and normal maps will become standardized and simpler. On the ZBrush side, we will continue to enhance these features, and will continue to share information with other companies to help streamline the process of rendering ZBrush-generated displacement and normal maps in their renderers.

Thanks
-Pixolator


Update May 9th 2004:

Here is one more displacement map test...



This test will better enable you to evaluate the accuracy of your test-render.

This displacement test is much less forgiving than the one above due to several factors...

1. Higher details ratio: 2.26 million polygons mapped into 138 polygons. Each low-res polygon represents 16384 high-res polygons.

2. The displacement is composed of geometric shapes, making any mapping distortions easily detectable.

3. The sides of the sword are perpendicular, causing abrupt changes of the normal directions within small areas.

Note 1: Since antialiasing and sampling of the displacement values are handled differently across applications, ZBrush can export the UV coordinates with or without a 0.5-pixel offset. Both files are included within the zip file. You may want to try both, to determine which one works better (i.e., is more seamless) in the external renderer.

Note 2: This test uses AUVTiles mapping. Normally, discontinuous UV mapping produces visible seam artifacts. To eliminate these artifacts, ZBrush automatically executes a smart seam-overpaint when the displacement map is generated. (The smart seam routine is optimized for AUVTiles/GUVTiles and other rectangle-based UV mapping. For other mapping methods the standard seam-overpaint is used)

Note 3: If your external renderer cannot make use of the full 16-bit resolution of the included displacement map, you may be able to improve the displacement render quality by first maximizing the grayscale contrast of the 16-bit displacement map, then reducing its depth to 8 bits.

Note 4: This test is provided because it's a very demanding displacement map. Since it requires a more accurate rendering, some visible artifacts in your test render, especially at the sharp edges of the blade, will be acceptable. Typically, mesh/displacement map combinations are less demanding, and artifacts (if there are any) are less likely to be noticeable.

Note 5: If you need to modify the included displacement file to better fit the format expected by the external renderer (i.e., by splitting the map to positive and negative displacements, or by reducing the map depth to 8 bits), please specify these steps in your post. In the near future, I plan to write a ZBrush plugin which will enable you to specify a target application, and ZBrush will export the map(s) in a ready-to-use format.


Click here to download the sword test files (Alpha gain=0.286)


Below is an alternate (easier to render) version of the Sword file.
This file is mapped with GUVTiles mapping...



... and the displacement map generated from Subdiv level 2 (instead of 1)
which reduces the HighRes/LowRes ratio to 4096 (instead of 16384).

Click here to download the alternate sword test files (Alpha gain=0.14)

hey, since I'm kinda new in maya in all. I was wondering if you could help me on this. I'm kinda dumn on this, but if you could show me a visual step by step on how to do this. The part that I'm stuck on is the displacement channels. Where to put the map to be exact. Do you put it as just a bump map? Or is there another step that I'm missing. thanks. I'm using maya6.