How do I composite an interactive 3D model in a scene?

[Angelo Lorenzo]

[Chase Gillman] “How does Lord of the Rings put Golem in the scene and have Frodo walk in front and behind him? Did they seriously create a mask around Frodo and go frame by frame moving the mask path?”

Yes, while there are techniques to avoid keyframing every frame (maximizing keyframe distance by breaking up one large mask into to multiple simple shapes), rotoscope work is tedious and exacting. VFX studios have entire departments dedicated to the process.

[Chase Gillman] ” Is there no easier way such as making an alpha channel from the original video? I know how to do this using a green screen, but can I do it without?”

You could try a difference mask if the camera doesn’t move. The background shouldn’t, within a margin of error to account for video noise, change while any motion of the actor should be picked up readily. Rarely as effective as rotoscoping because difference masking will fail so easily.

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Angelo Lorenzo

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