As a motion graphics artist, I can’t believe I passed this feature up for so long. So in case you’re like me, let me direct your attention to the “Preserve Underlying Transparencies” button in After Effects. It’ll save you a lot of time and help achieve some very sleek, simple effects.
Right next to the [blending] MODE option of any layer is a little box simply labeled “T”. This is the “Preserve Underlying Transparencies” box. Click it to activate, and After Effects will take the alpha channel (or “transparency”) of the layer directly beneath and it apply it to the current layer.
Why is this special? For one thing, it saves you the time of having to create custom shapes. You can over-draw a rectangle that needs to fit inside another shape and simply check the “T” box to hide the excess. You can also use this function to save yourself having to wrestle with layer masks, shape paths, or unnecessary PreComps.
Beyond lots of interesting and dynamic animations you can create, this feature above all saves time, which is precious in a world with deadlines.
Once you get the hang of it, try more complicated effects. For example, in the piece below (created for one of our clients, Social Health Institute) we built lots of different objects that a character would interact with. Then, by checking the “Preserve Underlying Transparencies” box, he disappears when traveling outside of the objects we created. That sequence was then PreComped and placed inside new composition with background art.
We’re excited to try out more techniques with this feature. Ideas? Feel free to share in the comments below!