For the project I'm working on, I created a cool little intro screen with a swinging street lamp. I key-framed the movements in order to make the swinging look realistic. And in order to make the spotlight, I added the CC Light Sweep effect to my solid black layer, and then drew a triangular mask around it. What I want to happen now however, is to make the text outside of the mask disappear. Essentially, I want to create a spotlight effect to only show the text within and mask.
I've tried experimenting with the alpha channels with no luck. I'm thinking it has something to do with an additional adjustment layer, or duplicating a specific file. I'm still new to After Effects, and feel like I've exhausted my well of limited knowledge. I'm hoping someone out there as a solution! I've included a screen shot of my project. Thanks!
If I understand correctly what you did, it should just be a matter of using the mask on your light layer on the text layer. You can use track matte or just copy and paste the mask with all keyframes.
A better way to do this is to have 3D layers- make text 3d, ad a light (spotlight) and apply Trapcode Lux on top. This will give you a 3d light cone with nice falloff and nice shadows. It will be just a matter of adjusting the angle of the cone for the spotlight in such a way that you will get the effect you're after.
I would avoid using a masked iteration of light sweep and use a real AE light. Then, as has already been said, you can make your text 3d and have it accept shadows. When the light rotates away from the text, it will disappear. As for making the light appear volumetric (i.e. so you can see the light 'in the air' as well as on the objects it illuminates), you COULD use a 3rd party plugin or you could go with a cheaper solution: this oldie but goodie tutorial from Maltaannon.