Dynamic Drop Shadows for Non-Shapes (Cast Proper Shadow On Rotate)

By default, when you rotate a bitmap, etc. in After Effects that has a drop shadow, the drop shadow will “stick” to the object and cast its shadow in the same direction as the rotation of the object. This is dumb!

(Shape layers don’t do this, fortunately.)

Let’s give bitmaps, etc. the Shape advantage!

1. Place your bitmap on the timeline.
2. Make it rotate: add an expression to the Rotation line and enter “time*30”.
3. Add a drop shadow: Effect > Perspective > Drop Shadow.
4. Under the Effects > Drop Shadow > Direction line for the shape, add an expression.
5. Clear our the contents of the expression and replace with: “value-transform.rotation”.

What you’ve just done is told the drop shadow’s rotation to equal the opposite of the object’s current rotation.

Bonus tip: Pick Whip tool (the spiral icon –  )

For step #5, you can set the expression by picking the target using the Pick Whip tool. See screenshot below.