How to Add a Stroke Mask in After Effects

Introduction

Stroke masks are commonly used to highlight areas of a video, create reveal animations, or add stylish outlines. In this tutorial, you’ll learn how to create a stroke mask effect in After Effects using masks and the Stroke effect.

Step 1: Import Your Video

Go to File → Import → File and import your video. Drag it onto the timeline.

Step 2: Create an Adjustment Layer

Go to Layer → New → Adjustment Layer. Apply the Gaussian Blur effect from Effects & Presets to the adjustment layer. This helps you clearly see the masked area while creating the stroke effect.

Step 3: Create a Mask

Select the adjustment layer. Use the Shape Tool (Q) or Pen Tool (G) to draw a mask around the area you want to highlight. Choose the appropriate Mask Mode (for example, Add or Subtract) depending on the desired effect.

Step 4: Apply the Stroke Effect

From the Effects & Presets panel, apply the Stroke effect to the adjustment layer. In the Effect Controls panel:
Set Paint Style to On Transparent or Reveal Original Image
Choose Mask 1 (or enable All Masks if you are using multiple masks)
Adjust Brush Size to control stroke thickness
Choose a Color for the stroke Step 5: Preview the Result

Preview your composition and fine-tune the stroke size, color, and blur amount to achieve the desired look.Conclusion

By combining Adjustment Layers, Masks, and the Stroke effect, you can easily create clean and flexible stroke mask effects in After Effects for highlights, reveals, and creative transitions.