How do I animate layer opacity in the compositor?

Hi Sean,


I'm working on a project where I have various collections in layers and want to animate the different layer opacities. Is it a good or bad idea to use the compositor to animate the higher level layer's opacity? E.g. imagine a human model where I want to animate the skin layer opacity to show muscles and bones.

I'm currently using After Effects to animate the opacity of layers that I've imported from   passes in the EXR file, but was wondering if this can be achieved using the compositor.

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  • Dwayne Savage(dillenbata3) replied

    Yes you can. Just use mix nodes or alpha over node and animate the factor. Just place mouse cursor over the factor and press I to insert keyframe. To see the key frames in dopesheet or graph editor you will need to have the node(s) selected or you can click on the arrow icon in their header to show all keyframes. 

  • Sean Kennedy replied

    Yep, exactly what Dwayne said! :)

    1 love
  • aaronstalling replied

    Thanks.

    Is there any tricks to getting the result showing in the 3D Viewport in Render Preview mode with the Compositor set to Always? 

    When I tried putting different passes other than the view layer into the Alpha Over node, everything in the 3D viewport disappeared and the message "Viewport compositor setup not fully supported"

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  • Martin Bergwerf replied

    Hi aaaronstalling ,

    Render Passes are (at least at the moment) not supported in the Viewport Compositor.

    2 loves
  • Dwayne Savage(dillenbata3) replied

    You use the image editor if you don't want to use backdrop. Once you add a viewer node the image editor will have an option in the image drop-down for viewer node.