For example in The first hobbit movie, they captured Andy Serkis acting as golum within a motion capture suit. However the model of golum is smaller than the actual actor, meaning if they overlayed the model ontop of the original footage it wouldn’t match up and you would still see the actor in the backplate.
How do big companies achieve this effect. Do they shoot the same scene 2 times for a backplate?
I’m just curious.