Using the Rotobrush Tool with a Graphics Tablet in After Effects I'm having a lot of trouble making this work. I select rotobrush tool, I put my pen down on the graphics tablet and suddenly I'm painting instead of rotobrushing. Why is this happening? Also it happens again even when I try to use the mouse instead. The rotobrush tool is selected, yet the effect is paint.
The roto-brush tool is a painting process - you paint green in the areas you want to rotobrush, red in the areas you don't, then tidy up edges with the feathering tool. See example here: