by slimed » Sat Mar 29, 2014 9:56 pm
if you're referring to what i think you're referring to: right click the clip, "video event pan/crop", at the bottom left hand of the dialogue box click on "mask" and check the box. then you can select the pen tool on the left and create anchor points around an object/character. and if you mean literally cut out, after tracing the character you can change the "mode" on the left to "negative"?
that said, i wouldn't recommend using sony vegas for masking, although it does suffice. from my experience the masking feature (or maybe the program itself?) isn't very frame accurate and it can be frustrating to work with.