Rotoscope Tracking

Hello all. I downloaded this free stock video from pexels, and wanted to remove the background. The plane is large however, so it would take a very long time to rotoscope out frame by frame. I figured rotoscope tracking was my best option, but Mocha Hitilm was having trouble folowing the plane because the angle the camera is seeing it at is constantly changing. Is there any way to get it to follow the plane better?


  • PalaconoPalacono Website User, HitFilm Beta Tester Posts: 3,442 Enthusiast
    edited July 2018

    When the plane is on the ground mocha would be the thing to use, and you'd need to break the plane up into several parts, just like you do with a person, so: wings, body, fuselage, engines, tail all separate and overlaid.

    Once it is off the ground and only against sky it gets a little easier. You can use Hue & RGB Key on the sky in RGB mode with the tolerance at about 9% and softness at 1% or so. This eats away the sky and parts of the plane. But, as nearly all the parts it eats away are surrounded by darker areas of the plane, you can get those back by having a fairly loose mask follow well inside the plane body, tail,engines etc. to recombine with the plane with the holes in. Rotoscoping these sections would be fairly easy as you'd just need to update them every 10-20 frames or so on a separate layer, and keep them inside the border of the shape where you are trying to patch the holes. So one for the tail, one for the fuselage and one for each engine should work OK.

    As the colour of the sky changes as the camera turns, you might want to set a few keyframes on the sky colour you are eyedropping - one at about 2/3rds of the way through and another at about 3/4 should do it - so it consistently removes the sky colour, even though it changes.

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