Chen Geng?
My first name is Chen, and my last name is Geng.
I prefer to be addressed by my first name Chen. I also go by "Ken" sometimes.
Possible pronunciation: Chen(ch-uhn) Geng(guh-ng).
My research lies at the intersection of 4D Computer Vision, Graphics, and Machine Learning. I'm broadly interested in data-driven modeling of the physical world and applications of such models in robotics and natural science. Currently, I'm obsessed with developing neural simulators for the (inverse) modeling of macroscopic mechanical systems.
Email: X × Y, where X = {gengchen}, Y = {@cs.stanford.edu}
04/2025: Our paper "Birth and Death of a Rose" is selected as an oral presentation at CVPR 2025.
03/2025: One paper is accepted to SIGGRAPH 2025.
02/2025: Two papers are accepted to CVPR 2025.
02/2024: One paper is accepted to CVPR 2024.
01/2024: One paper is accepted to ICLR 2024.
Invited Talks 🎤
Rethinking Inverse Simulation through the Lens of Lagrangian Mechanics[Abstract]
Abstract: Building simulation models for diverse physical systems from observational data is critical for many downstream applications, such as creating digital twins for robot learning. However, such inverse modeling remains challenging to scale: each new object requires selecting a category-specific physical model, then recovering its parameters through often-fragile system identification.
In this talk, we ask whether we can build a neural simulation system with a single governing structure that models diverse physical phenomena, from articulated rigid bodies to deformable solids, without category-specific equations. One natural design is to keep Lagrangian mechanics as the universal physical principle shared across these phenomena, while the category-specific structure is absorbed into generalized coordinates learned across categories from large-scale, multi-category 4D data. We show that the covariance of the Euler–Lagrange equations extends even to such overcomplete, learned coordinates, and simulate by solving these equations directly in the latent kinematic space, reframing inverse simulation as a generative modeling problem. The resulting system turns raw 3D shapes of diverse categories into simulatable assets in a feed-forward manner, with no physical annotations or per-object fitting, and generalizes to real-world scenes scanned with a phone.
     (* denotes equal contribution, ^ denotes student (co-)mentored, representative works are highlighted)
     For the comprehensive list, check out my Google Scholar page.
tl;dr: A feed-forward method for human performance capture that progressively updates a canonical space with incoming monocular RGB frames, using probabilistic regression to produce sharp novel-view renderings.
tl;dr: We decompose the shading of objects into a tree-structured representation, which can be edited or interpreted by users easily.
Abstract: We study the problem of obtaining a tree-structured representation for shading objects. Prior work typically uses the parametric or measured representation to model shading, which is neither interpretable nor easily editable. Our method uses the shade tree representation, which combines basic shading nodes and compositing methods, to model and decomposes the material shading. Such a representation enables users to edit previously rigid material appearances in an efficient and intuitive manner. In particular, novice users who are unfamiliar with the construction of such shade trees can quickly obtain such a representation. The extraction of such a representation enables the editing and understanding of object shading, even for novice users. The biggest challenge in this task is that the discrete structure of the shade tree is not differentiable. We propose a hybrid algorithm to address this issue. First, given an input image, a recursive amortized inference model is leveraged to initialize a guess of the tree structure and corresponding leaf node parameters. Then, we apply an optimization-based method to fine-tune the result. Experiments show that our method works well on synthetic images, realistic images, and non-realistic vector drawings, surpassing the baselines significantly.
tl;dr: We accelerate the learning of neural volumetric videos of dynamic humans by over 100 times.
Abstract: This paper addresses the challenge of quickly reconstructing free-viewpoint videos of dynamic humans from sparse multi-view videos. Some recent works represent the dynamic human as a canonical neural radiance field (NeRF) and a motion field, which are learned from videos through differentiable rendering. They generally require a lengthy optimization process. Other generalization methods leverage learned prior from datasets and reduce the optimization time by only finetuning on new scenes, at the cost of visual fidelity. In this paper, we propose a novel method for creating viewpoint-free human performance synthesis from sparse view videos in minutes with competitive visual quality. Specifically, we leverage the human body prior to define a novel part-based voxelized NeRF representation, which distributes the representational power of the canonical human model efficiently. Furthermore, we propose a novel dimensionality reduction 2D motion parameterization scheme to increase the convergence rate of the human deformation field. Experiments demonstrate that our approach can be trained 100 times faster than prior per-scene optimiztion methods while being competitive in the rendering quality. We show that given a video capturing a human performer of 100 frames, our model typically takes about 5 minutes for training to produce photorealistic free-viewpoint videos on a single RTX 3090 GPU. The code will be released for reproducibility.
tl;dr: Given sparse multi-view videos of crowded scenes with multiple human performers, our approach is able to generate high-fidelity novel views and accurate instance masks.
@inproceedings{multinb,
     title = {Novel View Synthesis of Human Interactions from Sparse
Multi-view Videos},
     author = {Qing, Shuai and Chen, Geng and Qi, Fang and Sida, Peng and Wenhao, Shen and Xiaowei, Zhou and Hujun, Bao},
     booktitle = {SIGGRAPH Conference Proceedings},
     year = {2022},
}
Experience 🧑🎓
NVIDIA June 2026 - Present, Santa Clara, California