When trying to cut a moving object out of a picture, let the keyframe interpolation and mask feathering work for you.
If you feather your mask a little bit, you don't neet to follow every tiny nook and cranny of the object you're cutting out. Obviously, the finer the detail, the less this will work, but generally speaking, the fewer anchor points on your mask, the better. If you're trying to isolate and object, for example, draw your mask a little bit outside the lines of your object, then feather in a little bit.
When you keyframe the mask along your timeline, don't go into it frame by frame, redrawing your mask one at a time. Instead, draw your initial mask, then jump ahead, say, 10 frames, and adjust your mask accordingly. Vegas will interpolate the mask along those ten frames, so the mask will move approximately with the object. Go frame by frame to check how close it is. Depending on the complexity of the object and the amount of shape change, you may find that you have to do little work between the keyframes -- especially if your mask feather is ideal.
If you feather your mask a little bit, you don't neet to follow every tiny nook and cranny of the object you're cutting out. Obviously, the finer the detail, the less this will work, but generally speaking, the fewer anchor points on your mask, the better. If you're trying to isolate and object, for example, draw your mask a little bit outside the lines of your object, then feather in a little bit.
When you keyframe the mask along your timeline, don't go into it frame by frame, redrawing your mask one at a time. Instead, draw your initial mask, then jump ahead, say, 10 frames, and adjust your mask accordingly. Vegas will interpolate the mask along those ten frames, so the mask will move approximately with the object. Go frame by frame to check how close it is. Depending on the complexity of the object and the amount of shape change, you may find that you have to do little work between the keyframes -- especially if your mask feather is ideal.
