I have been planning on this tutorial for a long time. Working on a project, I discovered that I could use a gradient shader in the Alpha Channel of a Material to work as a linear wipe in After Effects. I would control the start and end of the gradient using two nulls. With great excitment I pushed the technique even further and discovered that I could use the same principle to get a Spherical or cylindrical Wipe. I intended to do three separate mini tutorials on these. Later I found out that somebody else had posted something similar on the internet (Lasse Clausen, https://vimeo.com/109315806 (greetings to you, Lasse!)). At first I got discouraged, because I thought that this blew away my idea, but later I decided to to a tutorial on how create a Xpresso setup that incorporates all three Wipe Transition types. I wanted this setup to be as flexible and automated to use as possible. You can easily switch or add numerous gradient shaders to control with a single null. And if you don’t see any practical use for this preset, then it will surely count as a smart exercise in Xpresso. May be you would have to watch this video more than once to fully understand it. If you have questions, fell free to ask in the comments section.
Scene files: http://goo.gl/j40fi3