I'm having trouble with Apple Motion. I am trying to do a ligthsaber effect by adding a white square and a small part of the picture, as it appears in this tutorial: http://cpostudios.com/LightSaberTute_Part1.html . The problem is that for some reason, a little after I started recording the frames, my whole mask will appear moved. More over, some sort of ghost effect appears on it, leaving a trail of the white shape outside the mask.
Does anybody know what I'm talking about? What might be wrong in my settings? Thanks for your help!!