Right now After Effects doesn't offer a native effect for adding an Inner Shadow. The easiest way is using Layer Styles. Unfortunately, you need to twirl down several properties until you find what you need. I built the Inner Shadow preset to match Drop Shadow closely and added a little expression magic to fix some of the controls which I found confusing.
- Blend Mode: Change the blend mode of the Inner Shadow. I wish the Drop Shadow effect had this property.
- Shadow Color: The color of the shadow.
- Opacity: The opacity of the shadow
- Direction: This controls where the shadow is on the layer. The standard Angle control is not intuitive so I fixed it.
- Distance: The size of the Inner Shadow.
- Softness: How soft the shadow is. The Size control was too strong so I made some adjustments when using it.
I tried to mimic a native effect as much as possible. If you toggle the fx icon on/off the Inner Shadow will toggle on/off also. CS6+ compatible.
Remember, this is not really a plug-in. You'll need to install the preset by adding it to your Presets folder.
Windows: Adobe After Effects CC 2017/Support Files/Presets
Mac: Adobe After Effects CC 2017/Presets