I’m using weirdhat’s tutorial on compositing and video. I understand everything except for how he got the monkey to look like it was behind his hand. For my animation a glowing ball moves behind my body. My body doesn’t move and I added a plane to represent my body but I don’t understand how to make it still show the video, but make it so the ball disappears when it goes behind my body. If somebody could help please thanks.

I gave mine a shadeless material with the movie put on it with win mapping on.

Generally… to make something go “behind” something else, you must have a way to mask the thing that it’s supposed to disappear-behind. The usual means of doing such a thing in Blender is with alpha information … a fourth channel of information (in addition to R, G, B) that describes transparency. Then you stitch the whole thing together using the AlphaOver/AlphaUnder filters in the Sequence Editor.