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BenJH
Participant
April 30, 2021
Answered

Rotoscope mask acting erratic in main composition

  • April 30, 2021
  • 3 replies
  • 1353 views

Hi.  I'm very new to After Effects so I am not sure if I have done something wrong here.  I have rotoscoped some stock footage that I want to incorporate into a project.  I have created a precomp of the rotoscoped footage.  Within the precomposition the rotoscope works perfectly.  When I add the precomp to my main composition the mask begins to change and collapse in on itself.  When I double click back into the precomposition it is fine, no problems.  I thought it might be an error so I purged the memory and cache.  That seemed to fix the problem once, but as I made some more changes the problem came back.  I have purged again, but this time it has not solved the problem.  Is this an error with the preview or is my mask actually changing?  Anything I can do to fix this?

 

Thanks for the help!

This topic has been closed for replies.
Correct answer Rick Gerard

If the rotobrush has not been frozen you are going to have issues. 

 

Any time I use Rotobrush on a layer that is more than a couple of seconds long I pre-compose that layer moving all attributes to the new comp and opening the new comp. Now I have a separate composition that only contains one layer with Rotobrush applied and frozen. I then use the Composition menu to Pre-render that Rotobrushed layer and end up with a "lossless with alpha" copy of the footage that automatically replaces the nested comp in the project. I then delete the pre-comp, reduce the size and complexity of my project, add stability to the project, and reduce the final render time. 

 

I hope this helps. 

 

One more thing. When sharing images please use the Toolbar or drag them to the reply area and expand them. "The Drag &d drop here..." area is buggy and difficult to use for images.

3 replies

R
Community Expert
Rick GerardCommunity ExpertCorrect answer
Community Expert
April 30, 2021

If the rotobrush has not been frozen you are going to have issues. 

 

Any time I use Rotobrush on a layer that is more than a couple of seconds long I pre-compose that layer moving all attributes to the new comp and opening the new comp. Now I have a separate composition that only contains one layer with Rotobrush applied and frozen. I then use the Composition menu to Pre-render that Rotobrushed layer and end up with a "lossless with alpha" copy of the footage that automatically replaces the nested comp in the project. I then delete the pre-comp, reduce the size and complexity of my project, add stability to the project, and reduce the final render time. 

 

I hope this helps. 

 

One more thing. When sharing images please use the Toolbar or drag them to the reply area and expand them. "The Drag &d drop here..." area is buggy and difficult to use for images.

    B
    BenJHAuthor
    Participant
    May 2, 2021

    Thank you!   That did it!

    OussK
    Community Expert
    OussKCommunity Expert
    Community Expert
    April 30, 2021

    As KoMaruyama Say's, you should have the same frame rate for all your compositions 

    Ko.Maruyama
    Community Expert
    Ko.MaruyamaCommunity Expert
    Community Expert
    April 30, 2021

    If your precomped footage of the rotoscoped material isn't the same frame rate (or a stretched frame rate) in the main comp, the collapsed function may be changing when those roto keyframes land.

    In the Preomp's Composition Settings, make sure to check "preserve frame rate" - that may solve the issue.

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