[SOLVED] Houdini Depth pass artifact when using zDefocus (Nuke7)

[Cake Kid]

Hi everyone,

 

I can't really find any usefull information about this problem. I rendered my 3D model from Houdini with settings: VEX Type: float, Quantize: 32 bit float, Sample filter: Closest Surface, no pixel filter and everything else on default. And when try using zDefocus in Nuke using this depth pass, I experience weird artifact around the edges.

Am I rendering the depth pass in a wrong way, or there's something wrong in my settings in Nuke?

I'm attaching picture of the artifact - RGB and alpha version.

Thanks

Edited December 2, 2015 by Cake Kid

[Cake Kid]

I played with rendering settings and figured out that anti-aliasing gave grey values around the edges which of course the zdepth reads as something being very close right next to something being very far and that's why I got the edge artifact.

 

Blurring the zdepth makes it worse, so solution for this problem is to render zDepth pass (Pz) with following settings:

 

1. VEX type: float type

2. quantize: 32bit float

3. sample filter: closest surface

4. pixel filter: minmax idcover = object with most pixel coverage (no filter)

everything else i set to default

 

This solved my problem.

[NSugleris]

Yea.. never blur your zdepth, and if anything I've always found that a good depth pass will show aliasing.   We had a huge hullabaloo in our 3D dept when one artists was urging the depth pass has nice edges while another artist said you need to render out the depth pass at double res to get better edges, and we landed at getting that aliasy looking depthpass as a 32bit float as a seperate image.