1. A computer-implemented method of determining control values for controlling features of a computer-generated representation of a subject based on a performance of the subject, comprising: obtaining input data corresponding to a pose performed by the subject, the input data including position information defining positions on a face of the subject; obtaining an animation model for the subject, the animation model including adjustable controls that control the animation model to define facial features of the computer-generated representation of the face; matching one or more of the positions on the face with one or more corresponding positions on the animation model, wherein matching includes using an objective function to project an error onto a control space of the animation model; determining, using the projected error and one or more constraints on the adjustable controls, one or more values for one or more of the adjustable controls, the one or more values being configured to control the animation model to cause the computer-generated representation of the face to perform a representation of the pose using the one or more adjustable controls; and modifying the one or more adjustable controls to include the one or more values based on the projected error and the one or more constraints, wherein the modified one or more adjustable controls cause the computer-generated representation of the face to perform the representation of the pose.