An empirical rig for jaw animation

Abstract

In computer graphics the motion of the jaw is commonly modelled by up-down and left-right rotation around a fixed pivot plus a forward-backward translation, yielding a three dimensional rig that is highly suited for intuitive artistic control. The anatomical motion of the jaw is, however, much more complex since the joints that connect the jaw to the skull exhibit both rotational and translational components. In reality the jaw does not move in a three dimensional subspace but on a constrained manifold in six dimensions. We analyze this manifold in the context of computer animation and show how the manifold can be parameterized with three degrees of freedom, providing a novel jaw rig that preserves the intuitive control while providing more accurate jaw positioning. The chosen parameterization furthermore places anatomically correct limits on the motion, preventing the rig from entering physiologically infeasible poses. Our new jaw rig is empirically designed from accurate capture data, and we provide a simple method to retarget the rig to new characters, both human and fantasy.

3D Morphable Face Models—Past, Present, and Future

“…While most hair acquisition focuses on static reconstruction, some do capture hair in motion or estimate physical properties for hair simulation [Hu et al 2017a]. Especially challenging is the acquisition of partially or completely hidden properties, such a the tongue [Hewer et al 2018], the skull [Achenbach et al 2018;, or the jaw [Zoss et al 2019[Zoss et al , 2018, where oftentimes specialized imaging systems are required, such as Computer Tomography (CT), Magnetic Resonance Imaging (MRI), or Electromagnetic Articulography (EMA). Lastly, even skin itself requires specialized treatment in some areas, such as lips [Garrido et al 2016b] or eyelids [Bermano et al 2015], where the local appearance and deformation exceed the capabilities of the more generic methods.…”

TsFPS

“…DodecaPen [27] proposes an accurate pen-tip tracking approach by estimating the motion of a marked dodecahedron solid, an algorithm combines marker-based pose estimation and semi-dense photometric refinement is introduced to track the dodecahedron. The same method is adopted by Zoss et al [34,35] to collect motion data of the jaw animation accurately, but the performance of this method is greatly influenced by illumination variation, motion blur and occlusion. Our system can achieve relatively stable results even under those adverse conditions by introducing a robust region-based method.…”

“…These methods rely on feature-detection algorithms to obtain specific features, which means the feature-detection has a strong impact on the final tracking performance. By contrast, the marker-based method explicitly provides artificial features, which are usually considered to be relatively more stable and reliable [20], hence, it plays an irreplaceable role in object tracking area, especially for those scenarios require high accuracy [8], such as facial bones tracking [34,35], stylus tracking [27] and surgical instruments tracking [9,15].…”

“…The most closely related work to our own, DodecaPen [27], designs a marked dodecahedron solid for pen-tip tracking, it first does a rough pose estimation based on the detected markers, then a pose refinement step based on the photometric constraint is employed. Likewise, the same method is introduced by Zoss et al [34,35] to collect motion data of the jaw animation. However, this method suffers from illumination variation and motion blur, any environmental changes or occlusions happen may lead to bad tracking result or even failure.…”

Functionality‐Driven Musculature Retargeting

“…[HMD05] provided a comprehensive reference of muscle modelling parameters for lower and upper limbs. Anatomical modelling for specific body parts, such as face [SNF05, IKKP17], feet [PYL18], hands [SKP08, SSB*15], shoulders [VdH94, KVdH04, MT00], tongue [SLF12], and jaw [ZBBB18], has been explored for last two decades. Comprehensive full‐body musculoskeletal modelling and simulation systems are also available freely [DAA*07] and commercially [DRC*06].…”