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raw-m
07-16-2013, 08:50 AM
I'm using exrTrader for exporting my renders and I'm trying to set it up so I have to do as little passes as possible. I've used the Linear Fog/Matte Object trick in the past to great effect.

I'm sure I read somewhere that the Depth Buffer gets AA'd but looking at my render it doesn't appear to be the case. Could I be missing a setting somewhere that AA's my Depth buffer?

PS. Depth Buffer AA is enabled in Render Globals.

Galleddrim
07-16-2013, 01:03 PM
I did some tests on this last week, actually. It seems like the Depth Buffer AA setting in the Render Globals only affects AA if there are objects that overlap in the FOV. It does not AA the edges that have only background behind them. At least that is what it looked like. So if you need say, a black background, maybe create a black box and put your scene inside? That's the first thing that comes to mind anyway. I have yet to try it.

raw-m
07-16-2013, 03:35 PM
Thanks Galleddrim, that's interesting, I'll take a look at that. Is it possible to do that and keep an alpha channel?

Lightwolf
07-16-2013, 03:46 PM
Yes, you can make the item black in the alpha channel.

You can also use the depth limiter that's a part of the free db&w Tools for the same effect.

What's essentially happening is that there is AA... but the samples from the background are so extremely far away that any AA (which basically averages samples) and up being extremely far away as well... making it look like nothing happened (unless you look at the actual numerical values).

Cheers,
Mike

raw-m
07-16-2013, 03:55 PM
Thanks for clearing that up, Mike, makes sense.

When you say making an item black in the alpha channel, how you doing that (I'm sure I know, just give me a nudge :D)?

Lightwolf
07-16-2013, 03:58 PM
Thanks for clearing that up, Mike, makes sense.

When you say making an item black in the alpha channel, how you doing that (I'm sure I know, just give me a nudge :D)?
Item properties:Render

Enable Matte Object.
Alpha Channel: Constant Black.

Cheers,
Mike

raw-m
07-16-2013, 04:01 PM
:foreheads

Thanks Mike!

Lightwolf
07-16-2013, 04:11 PM
:foreheads

Thanks Mike!
Hehe, my pleasure.

Cheers,
Mike

raw-m
07-21-2013, 09:42 AM
Just another quick one on Z depth (the manuals are quite poor on this one)!

Render Globals/Use Z Buffer Min Max

Without this clicked on, what do the settings default to?

Also, when I turn it on and set the Min and Max values (I'm assuming it's in the meters) I get different results if I enter the same same settings in to exrTrader's Depth Min/Max. I'm a bit confused as to what's going on!?

I guess an approach would be that if I leave "Use Z Buffer Min Max" ticked off I use the Z depth buffer in exrTrader, if I click it on then I could use the Compositing Export Buffer.

Just an observation from playing around, the Render Globals/Depth Buffer AA doesn't do all that great a job of AA'ing on the broader areas - very steppy gradients.