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

[squeige]

Ok heres a maya default renderer test
same procedure as above just no surf approx setting, the only setting that changes is feature displacement is off and sample rate is 32 and 16 accordingly, guys one more thing make sure u have wrap u and wrap v off and maya has a default filter for all textures if u leave it on ull loose some details in your map so just set it to 0
RenderTime 16 secs... :P

[Zeddicus]

squeige: Lot's of banding in that last one. I take it this is Maya your using? So now I've seen this phenomena in two apps other than Max. I don't feel so bad anymore, lol. Nice to know I'm not alone hehe.

[squeige]

after testing the matter i found out its my bump map making all that banding, seems mayas default renderer sucks at bump mapping creates the banding effect, referred to as moire

[pooverfish]

For those experiencing stepping in the displacment map when using max and mental ray: try resaving the image as a 16bit RGB uncompressed tif file through photoshop.

If you check out the mental ray render messages it indicates that the .tif that came in the zip is not supported and it is passing the image as raw data: it looks like it converts it to an 8 bit format.

I resaved it to a tif format that it does support (as listed above) and it neither messaged that it was converting, nor rendered with the stepping that I was getting with the original tif.

cheers,
grant

[pooverfish]

Also, regarding converting from grayscale to RGB in photoshop: be aware that your colour profile settings may mean that the midpoint gray of the original grayscale image is converted to something other than 0.5, with the defaults I had it was visually darker and a -0.5 offset with the same displacement values used for vray was not rendering the same result in mental ray.

Once I had fixed my photoshop colour settings it then worked just fine.

cheers,
grant

[moob]

That seems to fix it converting to rgb though seems to change the neutral gray had to set the offset in max to -0.58

edit: nm you posted again

[jotajota]

saludos..aqui va mi experiencia con lightwave 7.5

[Zeddicus]

Hehe, just saw your post after asking about Max/MR banding in the other thread. FWIW, resaving in PS still gives the "format not supported / converting to RAW" error, so there is still banding as a result. I also tried both 16-bit greyscale and 16-bit color versions saved in PNG format which MR doesn't mind at all in Max, but still got identical banding to the uncompressed TIF. Like I said, not that big of a deal to me since I use Vray, but I'm curious and thought maybe I might be able to find a work around that could help folks stuck with MR. If only MR would obey changes to the blur setting like Vray does, then it would be problem solved most likely.

Edit: By the way, just thought I'd mention to all that if your renders (in any program) have a general mottled bumpiness in areas where it should be remaining smooth, then you more than likely are being bit by the banding gremlin too. I've found that certain settings can make clearly defined banding in one render, look like the bumpy surface of an orange peel in another (yes, the Lightwave post above mine prompted me to mention it). Converting to 8-bit instead of using 16-bit can do it for example. So can certain blur settings. Hoping this info helps you all get better renders in the future.

[ghopper]

quote:

---

Posted by Matthew
I was able to almost completely eliminate the banding caused by C4D's insistence on reading it as an 8 bit image.

---

Hi Matthew,
did you try to convert the displacement map to RGB. If you then load it into C4D it shows up as 24bit. Don't know whether it will make a difference though.

Also I tried your suggestions to use the blur settings, but it blurs out the finer displacement details too much I think.

Hopefully we can eliminate the banding soon and achieve the same displacement quality as Pixolator's image

[wierdPal]

squeige could I trouble you to post some screen shots of the process using default render in Maya that is similar to the ones cornel did for C4D 8.5 on the first page of this thread?

[Zendoftheworld]

Hi Zheads,

Here's my test - rendered in AIR Renderman renderer.



Using the same technique as per some of my previous tutorials and article featured in Highend Magazine Issue's 3 and 4


Best regards,
Zendoftheworld...

[MrBraun]

Rendered with Cinema4d 8.5 !
Saved displacement map to 8 bit not compressed and flipped vertically!
Hypernurbs render level 5.

Displacement 0.6m with Filter:
Brightness: -2%;
Contrast: 94%

Shader Oren-Nayar, rendered with Defaul Light no shadow!




Tnx Pixolator for this tread !!

[somlor]

Quick AIR test:


Workflow:

1. Download and install Liquid Maya plugin
http://liquidmaya.sourceforge.net/

2. Download and install AIR demo
http://www.sitexgraphics.com/html/air.html

3. Download Olivier's normalmap_displace.sl and compile it for AIR
http://www.drone.org/tutorials/rayDi...renderman.html

4. Import .obj into Maya. Select mesh.
Liquid>Attributes>Add Subdivision Surface

5. Set up render preferences with Liquid>Render Globals, position camera, add light(s) and render.

6. Open .RIB that was created in text editor and add:

# This determines the dicing rate for true displacement. The smaller the number the higher the micropolygon count.
GeometricApproximation "flatness" [.2]

# This turns on true displacement
Attribute "render" "integer truedisplacement" [1]

# This is the displacement bound giving the maximum distance the surface will be displaced. It seems that the ZBrush displacement gain # works nicely here.
Attribute "displacementbound" "float sphere" [.85]

# This applies Olivier's displacement shader to your object. Km is the displacement multiplier which you need to experiment with. I think I may have jacked it up a little too high.
Displacement "normalmap_displace"
"float Km" [5.5]
"string displace_map" ["DispTestHead_Disp16.tif"]

6 minute render time on my very slow Athlon with 768 ram and a zillion apps open at once.

[mondeo30]

Here's another render done in xsi, see the detail it get....

[somlor]

Some more AIR tests revealed persistent banding issues, particularly around the neck.

I seem to remember having some trouble with Olivier's shader in the past. I think it works better with a displacement AND normal map. Zendoftheworld, do you mind sharing what shader you are using and your settings? Is your shader capable of more detail? There are subtle details washed out in the render you posted.