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View Full Version : LW depth buffer..why so ugly?



spigolo
08-21-2013, 02:03 AM
I'm using the lightwave depth buffer for a motion graphic work, but I should say that the buffer generated makes it really unusuable..
The AA doesen't work..and the result generate a depth of field very fuzzy..
I know other people are compleining about that..I think Newtek should fix this asap as it's a crucial element for people that does compositing..

JonW
08-21-2013, 02:19 AM
I haven't needed depth much but did it a few times using Fog setting the min & max distance & 0% 100%

sukardi
08-21-2013, 02:26 AM
Hi Sigolo,

Did you render it to 16 or 32 bit. Rendering it to exr, I found it quite usable...

BeeVee
08-21-2013, 03:13 AM
You cannot antialias a depth of field buffer. The levels of grey denote the depth, so antialiasing, which adds levels of grey to smooth, would result in tearing.

B

spigolo
08-21-2013, 03:19 AM
Hi Sigolo,

Did you render it to 16 or 32 bit. Rendering it to exr, I found it quite usable...

No i didn't? did you set the depth buffer as a sequence of exr? and what EXR? there are 4 of them..

- - - Updated - - -

ok but why the result is so ugly?

sukardi
08-21-2013, 03:38 AM
I use LW_OpenEXR_MultiHalf (16 bit). The LW_OpenEXR_MultiFP is 32 bit.

It is right at the very top when using save to file in Compositing Buffer.

Lewis
08-21-2013, 04:41 AM
You cannot antialias a depth of field buffer. The levels of grey denote the depth, so antialiasing, which adds levels of grey to smooth, would result in tearing.

B

Hmm, so what does "Deph Buffer AA" button do then ? It's in render globals.

erikals
08-21-2013, 06:10 AM
if it can, i hope it gets fixed, until then i guess OLM Smoother is a partly solution...
OLM will not apply motion blur though, neither will a depth map afaik...
the solution might be to use a fog pass, see link below

seems if fixed it would increase rendertime...
http://forums.cgsociety.org/showthread.php?t=201038

Cageman, where are you...?

edit: some good answers here > (fog pass) (DPont DP_IFNE)
http://forums.newtek.com/showthread.php?107401-Depth-matte
older, but might still apply >
http://forums.newtek.com/showthread.php?10045-Depth-Buffer-Antialiasing-where

if you are a freelancer and want it 100% accurate fast, a cheat is to just paste the .mov into the background in Layout. now, just hit render. adjust the colors etc in post, the minus to this method is that you will then not have a depth buffer available in your post-application.

Lightwolf
08-21-2013, 06:16 AM
One thing to remember is that the AA essentially averages the depth values that make up a specific pixel. While this produces a decent result in most cases, it doesn't if the pixel (partially) covers the background.
The background in LW is _very_ far away - and as soon as that is a part of a pixel, the resulting average will still be extremely far away, making it look like no AA has happened against the background.

One way around it is to place a flipped, matte sphere with 0 alpha around the scene to provide a maximum depth for the depth buffer. Another option is to use the Depth Limiter pixel filter that's a part of the free dbb&w Tools.

And yes, save it as float since the depth buffer stores the distance from the camera in metres. Anything further away than 1m will thus be white in a non-float image.

Cheers,
Mike

djwaterman
08-21-2013, 07:02 AM
There's also the trick of rendering out the depth buffer at double size, it helps to reduce the jaggies some since there are gonna be more pixels packed into the frame. But it is a bit of a an extra step.

Lightwolf
08-21-2013, 07:08 AM
There's also the trick of rendering out the depth buffer at double size, it helps to reduce the jaggies some since there are gonna be more pixels packed into the frame. But it is a bit of a an extra step.
But that also requires a comp of all elements at twice the size and subsequent (after any depth relevant operations are done) scale down. Essentially it's like performing some of the AA in post.

Cheers,
Mike