View Full Version : Depth buffer AA doesn't work?

03-22-2009, 11:49 AM
Am I right if I say that the "Depth buffer AA" doesn't work? I'm comping something in fusion (fog) and I get nasty edges around my models. And if I just take a look at the depth map channel I see the edges are jagged.
I've switched depth buffer AA on and saved my image as an RLA. Also in the extended buffer viewer it's jagged. So did I miss something here or is that feature just broken? :twak:

03-22-2009, 03:33 PM
Are you using using a 32-bit format? My understanding is that a depth buffer for a 32-bit image does not anti-alias because its values are used to determine depth, not edges. And it's worse that just that because with 32-bit formats, you only get 8-bits of data for the depth channel. I believe this is an inherent limitation with depth buffers in 32-bit formats in any program.

Somebody please correct me if I'm wrong but I think this limitation doesn't apply if you use a floating point format like OpenEXR. It's what we use here at the Box, and I don't think we have the AA problem when using depth tools like the new Variblur in Fusion. I'll verify this when I get back into work this week.

If you are using .exr, let me know and I'll ask how we're handling the data here to prevent this problem.


03-22-2009, 03:54 PM
I was using exr in the beginning of my project but I was using the material buffer from the RLA for quickly changing colors of objects in my scene.

What you are saying makes sense (the float stuff) But why does the depth buffer AA button do then? If I use the buffer export and save it as a jpg there's no AA going on in the image. Also nog when I save it as an exr. In the normal save rgb output there's no depth buffer saved in the exr. Do I need to save it in a different manner? Or uhh?