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Activity Forums Adobe After Effects Delete background, leave moving objects

  • Delete background, leave moving objects

    Posted by Dave Woodrock on August 21, 2014 at 7:37 am

    I have two videos, one of them is an Scalextric black track, the other one in the same track with cars running in it.

    I want to take the difference, and leave only the cars running without track in the picture.

    So far I’ve tried:
    -Rotobrushing, but cars are too small.
    -Double the video track, move one of them a frame later, and make a blending mode in ‘difference’, so later on I can use that layer to get the differences.
    -‘Difference matte’ with the empty track video.
    -Different stuff with UnMult, but track is black (but shiny).

    In all cases, part of the track is showing (because of shadows and small reflections) or cars are swollen up. The video is beign taked at high shutter speed and cars are moving at the lowest speed, so minimum blur. Only hope I see is spray the track green/blue matte.

    Been lurking these past 5 years in CCOW, first post, be gentle to me!

    Dave Woodrock replied 11 years, 8 months ago 2 Members · 2 Replies
  • 2 Replies
  • Hannes Andersson

    August 21, 2014 at 3:08 pm

    you can not solve it with a combination of the difference matte and some color keys to remove only the shadows?

    Donuan
    Digital Artist / Film Maker / VJ / Animator
    https://donuan.tv

  • Dave Woodrock

    August 22, 2014 at 7:58 am

    Thanks for your answer Hannes.

    It ends up affecting the black in the track. And besides, the difference matte is not great.

    Right now we ended painting part of the track in green (turned out a great solution), but any other solution will be welcome since we’ll have to paint 65ft.

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