Glass Animation Tutorial: Keyframing Refraction & Light Sweeps in After Effects

Core Motion Principles for Realistic Glass

Rigid materials like glass must convey weight, inertia, and optical responsiveness during motion. When animating a glass UI card, you aren't just moving pixels—you are moving a physical lens through a dynamic light environment.

Step 1: The Inertial Card Entry Animation

1. Create a Null Object named [Card_Controller] and parent your glass shape layer to it.
2. Set Position keyframes: start the card 300px below the screen and animate to center over 24 frames.
3. Open the Graph Editor (Shift + F3). Pull the incoming bezier handle to create an exponential deceleration curve (Influence: 85%).
4. Apply a subtle Overshoot & Bounce expression to Position using Motion Tools V2 to give the card physical heft upon stopping.

Step 2: Synchronizing Light Sweeps with Camera Velocity

As the card decelerates, the angle between the viewer, the card surface, and the key light shifts. Simulate this by keyframing CC Light Sweep:

• Set Center coordinate from top-left (-200, -200) to bottom-right (1920, 1080).
• Match the Light Sweep speed graph to the deceleration curve of the card so the shine glints across the glass right as the motion settles.

Step 3: Handling Motion Blur with Optical Plugins

Native After Effects motion blur does not automatically calculate the blur of displaced background pixels inside adjustment layers. To achieve broadcast realism, apply ReelSmart Motion Blur (RSMB) on the final precomp to compute vector-based optical flow blur across the entire frame.