Jesse Toula has a new tutorial, Creating Pseudo Effects for AE, a full intro and update on custom effects:
"Pseudo Effects, sometimes called 'custom effect controls' and 'custom expression controls' allow you to put all of your controls into a single 'effect'. You can set your own defaults and value ranges so that users can use the reset button to return to the defaults you chose. There are many more advantages to using Pseudo Effects, and this tutorial will go over all of them as I walk you through creating one from scratch. The creation of these controls is done in an .XML file, so for those of you how do not feel comfortable writing your own code, or just want to speed up the process, I also end the tutorial by showing you a way of creating all of the XML without doing any programming by hand."
Custom effects are similar to Animation presets and to the more specific but limited examples in the Behaviors Presets in AE. "Pseudo effects" is the name originally given by Charles Bordenave (aka nabscripts at AE Scripts), who posted an "Effect Creator" script at AEnhancers in 2006.
Maltaannon popularized and deployed custom effects in a variety of ways starting around 2007. See his What CustomEffects are for an introduction to his tutorials and products.
Here's a smattering of some additional custom effect resources:
- Create Your Own Custom Effects! by Momcilo Stojkovic was the opener for a week of custom effects at AE Tuts. This text tutorial shows you how to modify and reimport PresetEffects.xml, so you can group and save expression controls as a unique filter/preset in After Effects.
- AE Tuts posted a cool preset and tutorial with Distribute Your Layers in 3D – Custom Effect by Rob Schofield. This preset effect is similar to part of RGS Plane Space (was 3D Assistants) and Create3DShapes and 3D Layer Distributor from AE Scripts.
- Topher Welsh rounds up 17 Custom Effects at AE Tuts; see also the AEnhancers library
- Pie Chart, a custom effect preset for AE by Jorrit Schulte (he collected his others with a video at Video Copilot)
- Ellipse Tool Plus from Hypoly (James Chiny)
- Eran Stern has a Creative Cow AE podcast, Markers Leaks, an introduction to his preset and Custom Effect with the same name, which he uses to trigger actions using layer markers inside of After Effects.