Ukramedia Has a Look at Creating a Rig That Will Let You Pick Colors By Moving a Null Around the Scene
Sergei Prokhnevskiy, a Senior Software Engineer at ukaerimedia.com shows how to create an effect in After Effects that allows you pick any color from anywhere on your screen using expressions and nulls as well! With this technique you can change the background of an element based off what’s underneath it- making onepiece design much easier than ever before.
This lets you simply move a null in the scene to change colors of an element, such as logo. This is thanks to Sergei’s sampleImage expression which reads color and alpha information from one layer and returns values for other layers it applies on top or below so they can be driven properly too!
This technique is nothing new. In fact, Dan Ebbert has written about using the sampleImage expression to access layer color in previous articles years and years ago!