enter image description hereI'm having trouble adding a render layer, the layers I have are:

  • Stars
  • Sky
  • Clouds
  • Billboard (problem)

I've managed to merge together stars, sky and clouds. However I'm having trouble adding the billboard layer. The rest show through one another but the billboard layer has a black background.

How can I make just that layer transparent?

  • 1
    $\begingroup$ Welcome to Blender Stack Exchange! You might in the future add more details to your questions, so it will be easier to identify the issue and solution. I hope I understood corretly. $\endgroup$ Aug 8, 2016 at 13:47
  • $\begingroup$ Was the billboard generated in blender? If so, just set the background to be transparent instead of black. $\endgroup$
    – user1853
    Aug 8, 2016 at 15:02

1 Answer 1


First Possibility

You might use the Color / Mix / Add node, or use the Color / Mix / Mix and with Fac of your billboards luminosity, which can be obtained with the Converter / Separate HSVA node.

Mix with Luminosity

Second Possibility

Insert a Converter / Math / Bigger Than node between the Separate HSVA and the Mix nodes abowe. This will only make totally black pixels transparent.

Third Solution

If your Billboard is rendered in Blender, you can set the background of the render to be transparent. In Blender Internal renderer set Properties Panel / Render / Shading / Alpha to Transparent. In Cycles renderer set the Properties Panel / Render / Film / Transparent checkbox to true.

  • $\begingroup$ Thanks for the help, its sort of done what I wanted it do to, however its made the model transparent as well (I've added a screen shot to my original post as that most likely would have been helpful the first time lol). $\endgroup$
    – Jordan
    Aug 8, 2016 at 14:23
  • $\begingroup$ I have updated my answere. $\endgroup$ Aug 8, 2016 at 15:02
  • $\begingroup$ Thank you, seriously!!! your second solution worked perfectly. Man I was so stressed about that. $\endgroup$
    – Jordan
    Aug 8, 2016 at 18:45

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