Locking a mask's position in After Effects prevents it from moving when you transform the underlying layer. There are several methods to achieve this, depending on your workflow and desired outcome.
Method 1: Using the Layer Padlock Icon
The simplest method involves locking the entire layer containing the mask. This prevents any changes to the layer, including mask modifications.
- Locate the Padlock icon to the left of the layer in the timeline.
- Toggle the Padlock icon to lock the layer in place. This will prevent any further changes to the layer's position, scale, rotation, or mask.
- For extra security, hide the locked mask via Layer > Mask > Hide Locked Masks. This removes it from the project view, but keeps the mask applied to the layer.
Method 2: Utilizing Track Mattes for Independent Movement
If you need to move the layer independently of the mask, use a track matte. This is ideal for revealing or concealing parts of a layer without affecting the mask's position.
- Create a solid layer above the layer with the mask.
- Create a mask on the solid layer, defining the area you want to reveal or hide.
- Set the layer with the mask as a track matte for the solid layer. This allows the solid layer (with the mask) to function as a mask to the layer beneath, even if their position changes.
Method 3: Pre-composing for Isolation
This method isolates the masked layer, allowing independent animation of the layer and its mask.
- Pre-compose the layer with the mask. This creates a new composition containing only that layer.
- Animate the position of the pre-composed layer within the main composition. The mask remains unaffected as its position is relative to the pre-composed layer only.
These methods provide various solutions for controlling mask behavior, allowing independent movement between the layer and its mask. Choose the technique most suitable for your specific needs.
