Toward Physically Stable Motion Generation: A New Paradigm of Human Pose Representation

Abstract

In machine learning, generating realistic human motion is paramount for a range of applications that require lifelike movements. Traditional methods have often overlooked the adherence to physical principles, leading to motion sequences that exhibit unrealistic behaviors such as foot sliding, penetration, and floating. These issues are particularly pronounced in complex tasks like dance choreography, which demand a higher degree of fidelity and realism. To address these challenges, we introduce RF-Rotation, a novel approach to human pose representation that strategically repositions the root joint of the SMPL model to align with both feet, while representing other joints through recursive bone rotations. It not only aligns more closely with the natural dynamics of human movement but also integrates an advanced contact predictor to ascertain the ground contact status of both feet, thereby preventing physically implausible movements on feet. We note that RF-Rotation is compatible with any motion generation tasks, including dance choreography, text-to-motion synthesis, and motion prediction, and can be seamlessly integrated into existing frameworks without modifications. Extensive experiments across three distinct tasks demonstrate the superior performance of RF-Rotation in enhancing the realism and stability of generated motion sequences. This method can significantly reduce foot sliding, floating, and penetration issues, without affecting computational efficiency, underscores its potential to set new standards in human motion generation.