facialrig

Facial rig, or facial rigging, refers to the process and result of creating a control system that drives the deformation of a character's facial geometry to produce expressive movements. It is a core part of character animation in film, television, and games.

Rigging typically combines a skeletal/joint-based structure with one or more sets of morph targets or blendshapes. A joint-based approach uses bones for key regions such as the jaw, brows, eyelids, lips, and cheeks to animate movement, while blendshapes store specific facial expressions and phonemes. Many pipelines use a hybrid approach, where joints define broad motion and blendshapes add fine detail and more natural deformation.

Control systems, or control rigs, translate animator input into character deformations. Controllers may drive individual joints, blendshape weights, or driven by expressions and constraints. Tools and practices include weight painting, skinning, corrective shapes, pose space deformation, and rig automation via set-driven keys or custom attributes. Rigging aims for an intuitive, robust interface that can be reused across characters with varying topology.

Common target regions include jaw articulation, eyebrow and eyelid motion, lip shape and smile, cheek puff, tongue and mouth interior, and overall facial symmetry. Facial rigs support lip-sync, gaze direction, blinking, micro-expressions, and speech-driven animation, often in combination with motion capture data.

Challenges include maintaining natural tissue deformation, avoiding unwanted distortions during extreme expressions, ensuring performance for real-time applications, and keeping rigs maintainable as character assets evolve. Proper calibration and testing across a range of expressions are critical for believable results.