Renderer Comparrison for ZBrush Displacement Maps

Become a member of the CGSociety

Connect, Share, and Learn with our Large Growing CG Art Community. It's Free!

THREAD CLOSED
 
Thread Tools Search this Thread Display Modes
  07 July 2005
Lightbulb Renderer Comparrison for ZBrush Displacement Maps

So i'm working on a female model with very limited hardware resources. Check it out here:
http://forums.cgsociety.org/showthread.php?t=261996

So I had to do a test to compare several methods of ZBrush displacement within max. I have to say the results weren't that good. But check it out below.

So now the obvious challenge comes to getting the model into 3d Studio Max. Since max's memory management and adaptive mesh algorithms (or rather lack there of) is really crappy so it can't really handle the 500k poly models that ZBrush can handle in real time.

So the obvious choice is of course ZBrush displacement maps in max so that the renderer can handle the high poly count per bucket at render time. So here are the results in the renderers that I actually have access to.

The Contenders
Mental Ray: Too slow for SSS and GI in my past experiences - didn't even try this one. If someone wants to post results that would be awesome!
finalRender: Blazingly fast GI algorithm... not so fast SSS algorithm. My favorite renderer... we'll see
VRay: Fairly fast GI algorithm with its irradiance map. SSS algorithm not really mature.

The Test
In the following lighting conditions 2 lights, both with ray traced shadows. See how long it takes to render a displacement map generated with ZBrush's displacement map feature with adaptive displacement maps. Here are the low poly control cage.


The Winner: Vray

The Results
Alternative Method
There is an alternative method to rendering high poly stuff with displacement in max. Throw a turboSmooth or meshsmooth modifier on it and crank up the render iterations to match ZBrushes. So that would be 5 for me.... unfortunately this CRASHED!

finalRender
So apparently finalRender's micro-triangle displacement algorithm is SUPER SLOW!! Check this out. The render took more than 2 minutes for 128x128 test render and I just stopped it because it was so slow.



VRay:
This ended up being the fastest using the Vray Displacement Modifier With the same setup as my pervious tests, this churned through the displacment map as if it were nothing. Check out the results below. Two different types of displacements were used.

Subivision: This, in theory should give the most accurate shapes. Unfortunately it leads to some artifacts of little bumps. Anyone know how to solve this?


2d (Landscape) This requires you to smooth out your mesh before you apply the displacement. This works just fine. But once again there are some different artificats. This time from the way the displacment map is set up itself since ZBrush outputs subdivision displacement maps.


And there you have the results.
__________________

 
  07 July 2005
just out of curiosty..what kind of image format are you using for the displacement map?
the 'Vray Subivision' method looks like an 8bit image is being used
 
  07 July 2005
While I'd agree that Vray handles displacement mapping the best out of the renderers you'd mention, I'd be curious to know more of your settings. From all of the tests that I've tried, FR's microtriangle displacements have rendered out much much faster than you are suggesting.
Also, were you using a 16bit TIF for the displacement maps, or 8bit? And what resolution? Insufficient resolution and a lower bit depth can give you banding issues. I'd imagine that filtering would play a large role in this as well.
 
  07 July 2005
VRay has fastest displacement, mental ray has almost as good as VRay and finalRenders MTD is extremely slow.
mental ray has the fastest SSS (fast-sss and diffusion shaders) not the slowest. Last time i checked finalRenders SSS doesn't support mtd. VRays sss is also good if you use irradiance map to interpolate it.
 
  07 July 2005
Quote: From all of the tests that I've tried, FR's microtriangle displacements have rendered out much much faster than you are suggesting.

yes, i second that. i guess AtmaWeapon has just used a too high subdivision level. i usually start with 2-3 and work my way up to 7 at max(it isn't that slow at those values at all). i found that it is sometimes even faster using a lower subdivision level like 4 and do extra subdivision by using turbosmooth. nonetheless, finalrenders MTD is far from being perfect, but as far as i know it's going to be updated in SP3, which gets possibly released after Siggraph(just guessing here).

Last edited by pd : 07 July 2005 at 08:34 AM.
 
  07 July 2005
edit: doublepost, sorry.
 
  07 July 2005
Arrow

While Vray's quality displacement is top notch, the best/fastest displacement way is using displace modifier + strong bump map. I get almost EXACT results in seconds.

Advantages:

Render time: a few secs
Works perfectly with scanline:
Compatible with all hair/plugins without need to compose
No need to buy 3rd party plugs (Mental Ray displacement is crap, it works worse than any, and when you get good quality (means small bump mapping detailing), render time gets shot to the moon)
It can render to texture
etc.

If you use bump mapping correctly tweaking bitmap levels inside max, the mesh isn't that complex, with 2-3 iterations for the displace modifier u're done.

That's what I've experienced

DDS
__________________
www.albertfeliu.com

Last edited by DDS : 07 July 2005 at 10:47 AM.
 
  07 July 2005
mental ray is fast. You just dont know how to use it.

Here is example:
1. 2 area lights.
2. 2 area lights, sss and displacement. Took 2min 20sec to render
3. 2 area lights, sss, displacement and final gather. Took 3min to render
Rendered on amd 1800+.
Attached Images
File Type: jpg mr_no_disp_sss.jpg (8.9 KB, 43 views)
File Type: jpg mr_disp_sss.jpg (18.8 KB, 51 views)
File Type: jpg mr_disp_sss_gi.jpg (19.1 KB, 84 views)

Last edited by Bercon : 07 July 2005 at 01:42 PM.
 
  07 July 2005
Second the Mental Ray is fast.

http://www.dis-assembly.com/skintest.jpg
 
  07 July 2005
Arrow

Originally Posted by MasterBercon: mental ray is fast. You just dont know how to use it.

Here is example:
1. 2 area lights.
2. 2 area lights, sss and displacement. Took 2min 20sec to render
3. 2 area lights, sss, displacement and final gather. Took 3min to render
Rendered on amd 1800+.


oh ok, if that what you call detail, then yes, MR is fast.

Any specs for your displacement values? This is a helping but not a staggering thread

Thanks.
__________________
www.albertfeliu.com
 
  07 July 2005
Post Thank you for all your replies

Hey guys, first of all I want to thank you all for your replies!

Quote: just out of curiosty..what kind of image format are you using for the displacement map?
the 'Vray Subivision' method looks like an 8bit image is being used

The displacement map is 1280x1280 for just the head alone and was exported using a tiff format. Also I'm using percision 16 in the Vray displacement modifier. Anyone got suggestions for this one?

Quote: mental ray is fast. You just dont know how to use it.
I have no doubt that MR is fast at displacement, I've done some tests when I was first picking up ZBrush, but the GI algorithms of MR although are incredible versitile, just aren't fast enough for my needs at the quality that I want.

Quote: the best/fastest displacement way is using displace modifier + strong bump map
I tried this in the tests, but when you up the subdivision iterations to the same amount as in ZBrush, my computer crashed and ran out of memory. You simply can't get the same kind of detail you get ZBrush using this method.

Quote: From all of the tests that I've tried, FR's microtriangle displacements have rendered out much much faster than you are suggesting.
Here are the FR settings I used: Subdivision level: 4, edge length: 10, depth and height at 4. Also, I was seeing some banding issues with this as well.

Quote: u should check out this thread: http://206.145.80.239/zbc/showthread.php?t=20310
Believe me, I've been following this thread for a very long time. Thanks!
__________________

 
  07 July 2005
Thread automatically closed

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.
__________________
CGTalk Policy/Legalities
Note that as CGTalk Members, you agree to the terms and conditions of using this website.
 
Thread Closed share thread



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
CGSociety
Society of Digital Artists
www.cgsociety.org

Powered by vBulletin
Copyright 2000 - 2006,
Jelsoft Enterprises Ltd.
Minimize Ads
Forum Jump
Miscellaneous

All times are GMT. The time now is 04:35 PM.


Powered by vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.