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View Full Version : Expression to tie opacity to brightness?



dondo
10-12-2007, 12:40 AM
I want to create a light beam effect that fades in an out based on a source clip's brightness. Its to mimic a light coming from a projector. Does anyone know of a way to do this?

Andrew Brinkhaus
10-20-2007, 02:47 PM
Not sure I understand exactly what you want to do....but give this a try. Go to the properties of the light beam, then go down to intensity and alt-click the stopwatch, then you can grab the pickwip (the wiggly line) button, and click and drag it to the source clips opacity. Now you have just linked the strength of the beam, to the opacity of the source clip. make sure they are both at 100% when you start though, or else they won't be calibrated.