# `GSComponent pieceValue(forKey:)`

*Instance Method*

The explicit interpolation value for a smart-component axis, or `nil` when the axis has no explicit value.

## Declaration

```swift
func pieceValue(forKey key: String) -> CGFloat?
```

## See Also

### Smart Components

- [`GSComponent.pieceSettings`](/Core/GlyphsCore/GSComponent/pieceSettings) — Explicit interpolation values for smart-component axes.
- [`GSComponent setPieceSettingsFast:`](/Core/GlyphsCore/GSComponent/setPieceSettingsFast:) — Replaces the smart-component settings without copying, undo, or change notifications.
- [`GSComponent setPieceValue:forKey:`](/Core/GlyphsCore/GSComponent/setPieceValue:forKey:) — Sets an explicit interpolation value for a smart-component axis.
- [`GSComponent removePieceValueForKey:`](/Core/GlyphsCore/GSComponent/removePieceValueForKey:) — Removes an explicit interpolation value for a smart-component axis.
- [`GSComponent valueForAxis:`](/Core/GlyphsCore/GSComponent/valueForAxis:) — The effective interpolation value for a smart-component axis.