Okay. I have the basirfx plgun for motion tracking on Vegas. And of course theres masking. But I need to know how people make a mask on something that's moving, like where a mask tracks a moving object, for ex like I'm running in a field and I want the 3d text from cinema 4d behind me but while I'm running, not a screen shot though. Any way I can do this? YouTube tutorial? I've seen this mask effect on soooooo many videos. Any clue?