turn on the view masks toggle (next to the safe areas toggle on the comp window) so you can see the mask and then use the arrow tool to click on a mask vertice. this will reveal all mask vertices – selected ones are solid and unselected are hollow. if you don’t click carefully AFX will select multiple mask points in that case shift click to turn on or off the ones you need. double clicking on a mask edge will bring up transform tools that will allow you to move, scale and rotate the entire mask. hit enter to get out of transform mode.
i will point out that it is way, way* easier to rotoscope with multiple masks (ie. one for the head, one for the left arm, one for the upper torso etc. etc.) that have fewer points than one big complicated one. it also helps because you can apply different levels of feathering to the different masks. also you may find it helpful to switch your mask to rotobezier mode (select your mask and find the option in the LAYER>MASK menu) and if you’re footage is interlaced (eg. 29.97i) to change your comp settings to 59.94 so that you’re applying keyframes on fields instead of frames.
mw
* way, way, way…