In After Effects, setting the transparency of a layer will affect the entire layer. What if you wanted to only pick the parts you want transparent, like create selective transparency? You could use a matte for that, but that could bet messy. The Set Matte effect in After Effects could be what you re looking for.
With it you can designate opacity in a layer pretty easily. Let’s say that you want part of a layer to be 50% opacity, while the rest remains true to the original color. Workbench’s Joe Clay can explain it visually for you where it will instantly make more sense.
Joe says about the technique: “we can have layers that are transparent when they cross other layers, and opaque otherwise. This way you can keep a client’s color palette accurate, or you can have layers be selectively transparent so only certain layers below show through.”
It’s a great tip for easily creating selective transparency so that layers can show through.