Soft Mask is an asset for Unity 3D that makes it possible to use semi-transparent masks in UI. It works just like standard Unity mask but supports alpha channel which allows you to make gradual and anti-aliased masks.
Soft Mask is available on Asset Store.
• Easy to use: just drop it on the Game Object in the same way as Unity’s standard Mask
• Supports Image, RawImage, Sprite and Texture
• Works with TextMesh Pro
• Allows separation of a mask from the masked hierarchy
• Can be easily supported in your shaders
• Fully real-time: create, destroy, enable, disable, move, rotate and reorder a mask and UI elements at runtime
• Can restrict input processing to only visible parts of the masked UI
• Adjustable mask sampling: use black and white images, images with transparency or set the weight of each color channel manually