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Antony1991
Antony1991
Participant
May 19, 2018
Answered

When I pre-comp, the background turns black!

  • May 19, 2018
  • 2 replies
  • 14944 views

Hello guys, I am slowly trying to learn after effects and there is a big question that always bugs me and I can't figure it out.

Say I have this comp, which is too cluttered, as you can see.

So I want to pre-comp it in order to clear the space, and of course in order to animate the whole spaceship at once.

The problem is that, when I pre-comp and then try to add a background image, the image doesn't appear and the new composition background stays black, no matter what I do.

Blending modes don't help.

And I don't know what to do. I have tried the shift channels effects and the linear color key effect, but i can't get them to work. Also, transparent grid is checked as the images show.

What is the solution here?

Thanks for any input!!

    This topic has been closed for replies.
    Correct answer Carlos Ziade

    Hi,

    Can you please try to create a new null object, then select all the spaceship layers

    that you want to animate and parent them to the null object using the pickwhip,

    if your layers are 3D don't forget to switch your null object to 3D as well.

    This way you will only animate the null object that will animate the whole spaceship at once

    That's as far as I understood your project construction

    2 replies

    C
    Community Expert
    Carlos ZiadeCommunity ExpertCorrect answer
    Community Expert
    May 19, 2018

    Hi,

    Can you please try to create a new null object, then select all the spaceship layers

    that you want to animate and parent them to the null object using the pickwhip,

    if your layers are 3D don't forget to switch your null object to 3D as well.

    This way you will only animate the null object that will animate the whole spaceship at once

    That's as far as I understood your project construction

    Antony1991
    Antony1991Author
    Participant
    May 19, 2018

    Thanks for the input!

    Yes, I just did it and it works, so at least as a work-around, I can move it.

    But what about applying effects on the whole spaceship? I will have to apply them to a layer and then copy-paste to all the other layers? Isn't that why pre-comp is here....?

    I still cannot understand why pre-comp creates a black background. Even if I pre-comp everything with a normal blend mode (not screen), the black background still persists.

    C
    Community Expert
    Carlos ZiadeCommunity Expert
    Community Expert
    May 19, 2018

    if we can see more of your workflow we can offer much more help

    you can use an adjustment layer above all the spaceship layers or

    you can precompose just the spaceship layers and not all your composition,

    but make sure to animate the null as explained and rasterize in the precomped

    and only use the precomp to apply the effects

    D
    Dave Merchant
    Legend
    May 19, 2018

    In your original comp the spaceship layers are all in screen mode. When you precompose them, they remain in screen mode but ONLY in the context of the pre-comp (where there's no longer anything underneath them, hence black). The PC's layer in your main comp reverts to normal mode, so that black background is displayed. By default AE doesn't care what's inside a PC, it just treats it as a chunk of video footage.

    Click the second-left toggle switch on your PC's layer, that looks like a sunshine icon. It's called Collapse Transformations, and it tells AE to look at the properties of each layer in the pre-comp before deciding how to render it into the parent.

      Antony1991
      Antony1991Author
      Participant
      May 19, 2018

      Thanks for replying Dave!

      I was aware of the Collapse Transformations button, and indeed when I press it, the layer gets fixed and the background image is shown.

      However the problem doesn't get fixed: if I apply ANY effect on the pre-comped spaceship, the black background returns. Collapse transformations seems to work only if you don't apply any effects on the comp.

      This kind of defeats the purpose, because why pre-comp something if I can't add any effects to it...

      Maybe I am doing something wrong before I pre-comp?

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