Implicit Bézier Motion Model for Precise Spatial and Temporal Control

Creating high-quality character animation remains an intricate and cumbersome process that requires skill, training, and craftsmanship to master. Recently, diffusion models have unlocked the ability to generate diverse movements from high-level condition signals such as text. For artist-friendly control, motion diffusion leveraging Bézier curves have been shown to allow precise joint-level conditioning. Yet, these works have been limited to joints at a fixed temporal stride, while animators require more temporal flexibility when keyframing or manipulating tangents to achieve animation principles such as easing in & out. In this work, we introduce a new Implicit Bézier Motion Model (IBMM), which during training is exposed to all possible configurations of control points, enabling control at arbitrary timings. This allows both precise and sparse joint-level control, anywhere in time and for any joint. In addition, we introduce a new quantitative measure of ease-in and -out, which leads to a novel condition over the motion generation process to reflect this artistic principle.