This is the first of a 3-part series on how to replicate the Priori Incantatem effect from the Harry Potter films. In this part, we will take a look at matchmoving our shot and using the data to create a 3D camera inside of After Effects, as well as starting to create the particle animation. Along the way, we’ll also go through a few quick tips on how to speed up workflow by using expressions to automate animation.