# blendShapes A dictionary of named coefficients representing the detected facial expression in terms of the movement of specific facial features. ``` var blendShapes: [ARFaceAnchor.BlendShapeLocation : NSNumber] { get } ``` ## Discussion Each key in this dictionary (an [`ARFaceAnchor.BlendShapeLocation`](/documentation/ARKit/ARFaceAnchor/BlendShapeLocation) constant) represents one of many specific facial features recognized by ARKit. The corresponding value for each key is a floating point number indicating the current position of that feature relative to its neutral configuration, ranging from `0.0` (neutral) to `1.0` (maximum movement). You can use blend shape coefficients to animate a 2D or 3D character in ways that follow the user’s facial expressions. ARKit provides many blend shape coefficients, resulting in a detailed model of a facial expression; however, you can use as many or as few of the coefficients as you desire to create a visual effect. For example, you might animate a simple cartoon character using only the [`jawOpen`](/documentation/ARKit/ARFaceAnchor/BlendShapeLocation/jawOpen), [`eyeBlinkLeft`](/documentation/ARKit/ARFaceAnchor/BlendShapeLocation/eyeBlinkLeft), and [`eyeBlinkRight`](/documentation/ARKit/ARFaceAnchor/BlendShapeLocation/eyeBlinkRight) coefficients. A professional 3D artist could create a detailed character model rigged for realistic animation using a larger set, or the entire set, of coefficients. You can also use blend shape coefficients to record a specific facial expression and reuse it later. The [`ARFaceGeometry`](/documentation/ARKit/ARFaceGeometry) [`init(blendShapes:)`](/documentation/ARKit/ARFaceGeometry/init(blendShapes:)) initializer creates a detailed 3D mesh from a dictionary equivalent to this property’s value; the serialized form of a blend shapes dictionary is more portable than that of the face mesh those coefficients describe. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)