# `GSGlyph interpolateFull:masters:scale:keepSmart:layerName:additionalLayers:error:`

*Instance Method*

A detached layer interpolated for an instance, or `nil` when interpolation fails.

## Declaration

```objc
- (GSLayer *) interpolateFull:(GSInstance *) instance masters:(NSArray *) masters scale:(CGFloat) scale keepSmart:(BOOL) keepSmart layerName:(NSString *) layerName additionalLayers:(NSMutableArray *) additionalLayers error:(NSError **) error;
```

```python
interpolateFull_masters_scale_keepSmart_layerName_additionalLayers_error_(instance: GSInstance, masters: list, scale: float, keepSmart: bool, layerName: str, additionalLayers: list) -> tuple[GSLayer, NSError]
```

## Parameters

- `instance` — The instance that supplies the interpolation location and settings.
- `masters` — The font masters participating in the interpolation.
- `scale` — The coordinate scale applied to the result.
- `keepSmart` — Whether Smart Components remain components when possible.
- `layerName` — The name of corresponding source layers to interpolate, or `nil` for the primary layers.
- `additionalLayers` — A collection to which interpolated color and corner layers are appended, or `nil` when they are not needed.
- `error` — On return, an error that prevented interpolation.

## Discussion

This method accounts for active Intermediate and Alternative layers, Smart Components, and pre-interpolation filters. The source layers must have matching structure.