A dictionary of named coefficients representing the detected facial expression in terms of the movement of specific facial features.
- iOS 11.0+
Each key in this dictionary (an
ARBlend 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 (neutral) to
1 (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
ARBlend 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
init 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.