View Full Version : Z-depth and planes with transparency
08-17-2007, 08:03 PM
I would like to render my images together with a z-depth channel. That's no problem and it work to get my DOF in Photoshop.
But I have a problem:
- In my scene I have some tree, wich are simples planes with a texture on it and a alpha map. In the alpha channel i see the tree nicely. But in the z-depth channel I see the plane instead of the tree. Is there any solution ?
08-17-2007, 08:37 PM
Using a reverse node from your alpha and plugging it into matte opacity should solve the problem.
08-17-2007, 08:46 PM
Thank you very much. But i do not understand exactly what you mean.
Do i deconnect my connection t the transparency and than mak e a new connection with a reverse node to the matte opacity ?
08-17-2007, 10:03 PM
No - don't do anything with your transparency connections.
You want to tell the renderer that when transparency = 100% then matte opacity must be 0%. Connect the alpha out from your transparency map to a reverse node's input. Then connect that reverse node to Matte opacity.
This should work. I haven't tested it and it could depend on other factors such as what file format you are using for z-depth, whether your alpha channel is "embedded" in your texture or if you're using "Luminance is alpha" from your file node etc.
Let me know if this works.
08-20-2007, 05:36 PM
you could also try Puppet's awesome Z shader - http://puppet.cgtalk.ru/download/z_e.shtml
08-20-2007, 06:23 PM
I tried to connect the reverse node to the alpha, but i do not know wich channel to connect. It asks for the x, y or z.
When I connect one the z-depth does not look right.
08-21-2007, 09:42 AM
Aah yes. Alpha is only a single channel (256 greyscale) rather than colour which would have 3 channels R,G and B (which could connect to x,y,z respectively) - so you would use any one of the channels x,y or z. Connect alpha to say x then connect the output x of the reverse to matte opacity.
08-21-2007, 09:42 AM
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