---
title: HoverEffectComponent.OpacityFunction.mask
framework: realitykit
role: symbol
role_heading: Case
path: realitykit/hovereffectcomponent/opacityfunction/mask
---

# HoverEffectComponent.OpacityFunction.mask

Applies a hover effect with full opacity when the opacity of the entity’s base material is greater than five percent.

## Declaration

```swift
case mask
```

## Discussion

Discussion The hover effect fades out with the base material when its opacity is less than 0.05. In this example, a rounded black rectangle continuously transitions between transparent and fully opaque. Applying a green highlight hover effect to the rectangle only displays the hover effect when the rectangle is at least slightly opaque. The hover effect doesn’t draw when the rectangle is transparent.