Method 1: Using the Pan Behind Tool

How Do I Move an Image Inside a Mask in After Effects?

Moving an image within a mask in After Effects is easily achieved using a few different techniques. The best method depends on your desired workflow and whether you want to maintain the mask's position relative to the image or vice versa.

This method is ideal for simple movements where you want the image to move within the confines of the mask.

1. Select your image layer. Ensure your image is placed on a layer above the layer containing the mask.
2. Press Y on your keyboard to activate the Pan Behind tool.
3. Click and drag within the mask's area to move the image. The mask will remain stationary.

Method 2: Pre-composing for Independent Movement

This approach provides more control, especially for complex animations or when you need to scale or rotate the image independently of the mask.

1. Select your image layer and mask layer. Select both the image and its associated mask layer.
2. Pre-compose the layers. Right-click and choose "Pre-compose." In the Pre-compose dialogue box, ensure the "Move all attributes into new composition" box is unchecked. This keeps the mask and image position separate.
3. Move the image layer within the pre-composition. Now you can freely move, scale, and rotate the image layer within the pre-composition without affecting the mask layer's position.

Method 3: Using Separate Layers for Mask and Image

This technique allows for ultimate control and flexibility but might seem a little more involved.

1. Create a solid color layer beneath your image layer.
2. Create your mask on the solid layer. Draw the mask shape you want for your image.
3. Position the image layer above the mask layer. The mask automatically reveals the desired portion of the image. Move and animate the image layer independently from the mask.

Troubleshooting and Additional Tips

• Track Matte: For a more sophisticated solution (especially for complex reveals), consider applying a track matte to the image layer using the mask layer as the alpha channel. This creates an accurate mask that adapts seamlessly to the image’s movement.
• Anchor Point: Adjusting the anchor point of your image layer can make positioning and movement more intuitive within the mask.

Remember to choose the method best suited to your specific requirements and project complexity. The Pan Behind tool is great for simple movements, while pre-composing or using separate layers offers more control for complex animations.