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I am trying to figure out how to work with render layers. Now I have two render layers connected to the output via Alpha Over node. But when I render the composite output layer is not the combined output of the two separate render layers. What is my stupidity?

enter image description here

p2or
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  • related: http://blender.stackexchange.com/questions/7573/how-do-i-composite-render-layers-in-2-69-using-cycles, more explanation: http://blender.stackexchange.com/a/3003/3710 – p2or Sep 10 '15 at 11:43
  • Cycles or internal? The question is tagged with cycles, but you are using internal (screenshot). – p2or Sep 10 '15 at 11:58
  • I edited my question. How to get the composite output I want (the combined render layers) ? –  Sep 10 '15 at 13:12
  • You want to have both cubes, right? Please try to explain what is wrong with 3pointedit's answer and what you don't understand exactly. – p2or Sep 10 '15 at 13:27
  • done. see my added comment –  Sep 10 '15 at 14:25
  • I think I understand this idea of transparency now. But this means that if i want a combined layer of two render layers (with a background) I have to define a third render layer that consists of both individual render layers ? –  Sep 10 '15 at 15:05
  • Let us continue this discussion in chat. –  Sep 10 '15 at 15:06

1 Answers1

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It could be that you are not actually providing the compositor with any transparency. The alpha output socket from the scene node will just be a solid white unless you check the following properties:

Blender Internal: Turn on Shading > alpha > transparent, in render properties.

Cycles: Turn on film > transparent, in render properties.

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3pointedit
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  • Thanks for explaining how to work with transparency / alpha channels. Maybe I was not very clear in my question. I have now added a new picture showing the composite layer in cycles blender. Why is only one render layer in the composite layer ? I want both render layers in the composite layer. How to do that ? –  Sep 10 '15 at 14:23
  • @JanScherders Simply because your images (see the render layer preview window) are not transparent. As I suggested, read this post carefully. Here is a blend, open it and hit F12: http://blend-exchange.giantcowfilms.com/b/488/ – p2or Sep 10 '15 at 15:05