I'm having a few issues with Pz and deep rasters …

In the RGB test below, the filmstrip is a solid ribbon with a single texture map applied via a simple VOPs-based shader. The holes/notches in the filmstrip are fully transparent areas of the RGBA texture. As I'd like to add some depth cues (fog and blur) in composite, I render Pz as a 32-bit float in a deep raster.

With reference to the Pz image, you can see that (i) some of the holes are missing entirely (lack of any further geometry) and (ii) the shade inside of the holes is not correct. With respect to point (ii), like the RGB image, it should be the same shade as the ribbon in back. In the mantra ROP's Deep Raster tab, I have the sample filter set to “Opacity Filtering” with pixel filter “minmax max”. (Within the shader, the opacity of these holes/notches is that shown in the alpha image below.) I would have thought this should work?

On a somewhat related note, within the compositor how do you convert a 32-bit plane to 8-bit? I ended up doing a screen capture from mplay as I couldn't get the Pz plane into 8-bit format. I tried the convert COP with all manner of settings for black/white points.

The problem is that your opacity doesn't reflect alpha channel. If you are defining transparency with alpha channel you have to use it also as a opacity multiplier (inside your shader VOP)

I've made some explanation chart on similar topic once (first row):

http://img55.imageshack.us/img55/3223/opacitypasslg5.jpg [img55.imageshack.us]


As to conversion you have to append equalizeCOP before ConvertCOP (if I remember right, can't check now)


cheers,
sy.

SYmek
The problem is that your opacity doesn't reflect alpha channel. If you are defining transparency with alpha channel you have to use it also as a opacity multiplier (inside your shader VOP)

I thought I was doing this already. My shader's Of = (alpha,alpha,alpha).

I'm sorry for a confusion! Just didn't read your post careful… ops:


Two steps more:

1. Create new export variable like: _Pz and multiply global Pz with your alpha (because I think you cannot override Pz it self - but maybe you can..?)

2. Change “Sample Filter” for this new variable (_Pz) in ROP's deepraster settings from “Closest Surface” to “Opacity filtering”

done!

hope this will work!
cheers,
sy.

Hi SYmek, thanks very much … it works perfectly.

Actually, looking at the image more closely, I probably want to add a VOP so that the Pz multiplier can only be 0 or 1 (nothing in between) …