I've been playing around with AE now for about a day and I love it!... but I'm stuck trying to make lines (or an image) display in a shape but hide when outside the shape, but still keeping the background image or video.
Is this possible?
I thought that this would be done with a mask. Am I right?
I have attached an image to make it a littler easier so you know what i'm on about :D
The lines will be animated to move along the red shape from right to left, but as you can see its a strange shape and I want the green lines to hide when they are out of red shape but still keeping the image in the background (currently black)
If all of the green lines are on one layer and the red shape on another layer. You can duplicate the red shape, put the duplicate above the green lines layer and set the track matte of the green lines layer to alpha. This will use the red shape as a "cutout." There are a dozen different scenarios, so it might be better to see you timeline.