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

[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)

[system]

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

Attachments

[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.

[phx.official]

First of all, try this tutorial from “sunit”:
http://archive.zbrushcentral.com/zbc/showthread.php?t=22176

You can open the Approximation Editor as shown in the first image. After making your settungs there (discribed in the tutorial), you push the “output connections” button (marked with red dot) of the ShaderNode to go to the ShadingGroupNode. The InputNode gets your DisplacmentTexture (markedwith yellow dot). You will get a DisplacementNode, too. Don’t delete this.

With you FileNode open, you have to edit the AlphaGain and AlphaOffset. (marked with blue dot) First type in the Value, you got from ZBrush in the AlphaGain field. If you scaled your model in Maya, you have to rise this value too, even if you freezed transformation afterwards. The AlphaOffset is the negative half of AlphaGainValue. Type it in, or use the expression of the tutorial

I’ve scaled my model to 3.1
In the first image i used the values i got from zBrush, and you see it very smooth but is missing details. The second one is made with values multiplied with 3.1 and now the details are good, but at the tip of the thorns, it’s ugly.

This is o.k., with Gain 0.350 / Offset -0.175

This is the original mesh in ZBrush and a NormalMap rendering with Maya SoftwareRenderer. Very fast, and good quality but I’didn’t get any good results mith NormalMaps and MentalRay yet. I tryed different tutorials and shaders, switched and mixed the colors but nothing.

Don’t blame me for my grammars, my nativ language is german

[CharlesWoods]

Bet you thought this thread was dead and gone!
Lightwave 8.3 on XPPro.
Subpatch level of 15 (612k polygons)
Using Lynx’s NormalDisplacement plugin and an 8bit grayscale
conversion of the ZBrush map.
Same map is used in the bump channel at 200%
Lightwave doesn’t support subpixel displacement at this time,
so using the bump mapping helps to beef up the detail.
FPrime 1.5 Render with a generic three light setup.

[jojolo]

Maya 7 & Mental Ray
24 seconds

[bkulyk]

WoodyLWG: Can I get a step by step of your process. I have been trying to render this sample for a week with no results. Also attachment you posted does not work. Thanks for your help.

[PixelDroid]

http://archive.zbrushcentral.com/zbc/attachment.php?attachmentid=16628&stc=1

Woody, the link doesn’t go to a page w/images on it.

MR

[Suzana]

Hi
My first little contribution.
6 lights
MR

[ilusiondigital]

Vray displacement, we can see a few black points in the face.

Attachments

[metamesh]

Hi
IlusionDigital, i’m not sure but maybe u didn’t use any antialiasing for the image? that could be the reason for the black spots, if u activate it it will probably fix that…

[ilusiondigital]

Yes, Metamesh. I forget activate the AA mode

Thanks

[ksgant]

Here is a version in 3dsmax 7 and Maxwell renderer:

This took about 20 minutes. I don’t have a precise time because I stopped the render around then.

[metamesh]

KSGAN hi,
i see that u used maxwell for that image, how is the displacement in maxwell? is it an own mawell displacement or just a displace modifier over meshsmooth? thanks man!

[ksgant]

This is just the displacement modifier in 3dsmax then rendered in Maxwell.

[ilusiondigital]

Another vray displacement

Attachments

[samysuns]

I want to bring the low res mesh into ZBRUSH and use this displace ment map

to make a highres , is it posible? how is the workflow? thanks

[Jason_Belec]

Welcome samysuns, what you want is possible. Many posts on the forums explain this for the various apps people use outside Zbrush, and simple search will yield many great tips.

In essence, load your mesh into Zbrush, store a morph (unless you are going to radically alter the surface - then you can use cage near the end), model away, using whatever tools, subdivide as needed, model more, then when done, revert back to the original geometry and create displacement or morph or normal or all. This is really glossy of course.