Tianyi Xie

Tianyi is a Research Scientist at NVIDIA Research. He did his Ph.D. at the University of California, Los Angeles, where he was advised by Chenfanfu Jiang and Demetri Terzopoulos. He received his B.Eng. in Software Engineering from Shanghai Jiao Tong University. His research focuses on bridging physics-based simulation and generative AI, embedding physical priors into generative pipelines to produce visually compelling and physically consistent content, with applications spanning computer graphics, embodied AI, and robotics.

CRoCoDiL: Continuous and Robust Conditioned Diffusion for Language

Masked Diffusion Models (MDMs) provide an efficient non-causal alternative to autoregressive generation but often struggle with token dependencies and semantic incoherence due to their reliance on discrete marginal distributions. We address these limitations by shifting the diffusion process into a continuous sentence-level semantic space. We propose CRoCoDiL -- Continuous and Robust Conditioned Diffusion for Language --  a unified fine-tuning approach that jointly trains an encoder–demasker architecture, grounding the MDM demasking in continuous latent representations.

Timing Matters: The Impact of Event-Specific Frametime Spikes in First-Person Shooter Games

Frametime spikes can disrupt gameplay in first-person shooter (FPS) games, affecting both performance and player experience. This paper examines how spikes during specific game events impact players. We developed a custom FPS game that maintains a steady 500 frames/s while inducing frametime spikes during weapon reloading, fast mouse movement, or targeting. Thirty-eight (38) participants played the game in a user study, providing both performance data and user-reported visual smoothness.

Lead Rush: A First-Person Shooter for User Studies and Understanding Effects of Frame Time Spikes

User studies are a cornerstone of human-computer interaction research, including measures of user performance and quality of experience (QoE) – particularly important for games where frame rates and frame timings can impact performance. Unfortunately, commercial games have limited options for customization and do not log player performance data with sufficient detail for use in such studies. This paper introduces Lead Rush, a first-person shooter game designed for conducting user studies on the effects of frame timing and frame rate.

Impact of Graphical Fidelity and Frame-Time Stutter in a First-Person Shooter Game

Frametime spikes and graphical fidelity both matter for the feel of first-person shooter (FPS) games, yet their combined effects are not well understood. This paper examines how graphics settings and frametime spikes during aiming interact with player performance and experience. We developed a custom FPS game with configurable textures, lighting, and visual effects, and induced frametime spikes of 0 ms, 225 ms, or 675 ms during play.

Editing Physiological Signals in Videos Using Latent Representations

Camera-based physiological signal estimation provides a convenient and non-contact way to monitor heart rate, but it also raises serious privacy concerns because facial videos can leak sensitive information about a person’s health and emotional state. We present a learned framework for editing physiological signals in videos while preserving visual fidelity. Our method first encodes an input video into a latent representation using a pretrained 3D Variational Autoencoder, and embeds a target heart-rate prompt through a frozen text encoder.