View Full Version : Z-depth and planes with transparency

08 August 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 August 2007, 08:37 PM
Using a reverse node from your alpha and plugging it into matte opacity should solve the problem.

08 August 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 August 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 August 2007, 05:36 PM
you could also try Puppet's awesome Z shader -

08 August 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 August 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.

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08 August 2007, 09:42 AM
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