If you are poking around the net looking for an easy to follow guide for working with Expressions and Fusion Macros, here is a good one for you. Motion Designer Simon Ubsdell walks through the process of using basic expressions and how to create macros in BMD’s lighting-fast compositor.
You can work with simple expressions, groups and Fusion macros to automate repetitive tasks and build tools to assist with your work. Fusion expressions are a type of scripting, that can be placed along side the controlling parameter. It’s great for calculating things, building a uni-directional parameter connections, or both.
Fusion Macros and groups offer a way to combine a series of operations with a parameter control. You can bundle individual tools to reduce clutter, add proper use and interaction and speed up your workflows.
Simon takes us through using both expressions and macros, while creating a chromatic aberration effect using the techniques. Great if you are just starting out.