Adobe After Effects
After Effects: Using the Roto Brush
In this After Effects Tutorial VideoFort Jon give a quickoverview on how to use the Roto Brush. With your footage imported into a new comp, select the roto brush tool at the top (next to the puppet pin tool). Go into the footage layer and draw a line down the subject you want to roto. Now you can scrub through and adjust the Roto mask as needed by adding or subtracting from the roto mask.
