Shen, Tianchang
Cosmos-Transfer1: Conditional World Generation with Adaptive Multimodal Control
NVIDIA, null, :, null, Alhaija, Hassan Abu, Alvarez, Jose, Bala, Maciej, Cai, Tiffany, Cao, Tianshi, Cha, Liz, Chen, Joshua, Chen, Mike, Ferroni, Francesco, Fidler, Sanja, Fox, Dieter, Ge, Yunhao, Gu, Jinwei, Hassani, Ali, Isaev, Michael, Jannaty, Pooya, Lan, Shiyi, Lasser, Tobias, Ling, Huan, Liu, Ming-Yu, Liu, Xian, Lu, Yifan, Luo, Alice, Ma, Qianli, Mao, Hanzi, Ramos, Fabio, Ren, Xuanchi, Shen, Tianchang, Tang, Shitao, Wang, Ting-Chun, Wu, Jay, Xu, Jiashu, Xu, Stella, Xie, Kevin, Ye, Yuchong, Yang, Xiaodong, Zeng, Xiaohui, Zeng, Yu
We introduce Cosmos-Transfer1, a conditional world generation model that can generate world simulations based on multiple spatial control inputs of various modalities such as segmentation, depth, and edge. In the design, the spatial conditional scheme is adaptive and customizable. It allows weighting different conditional inputs differently at different spatial locations. This enables highly controllable world generation and finds use in various world-to-world transfer use cases, including Sim2Real. We conduct extensive evaluations to analyze the proposed model and demonstrate its applications for Physical AI, including robotics Sim2Real and autonomous vehicle data enrichment. We further demonstrate an inference scaling strategy to achieve real-time world generation with an NVIDIA GB200 NVL72 rack.
InfiniCube: Unbounded and Controllable Dynamic 3D Driving Scene Generation with World-Guided Video Models
Lu, Yifan, Ren, Xuanchi, Yang, Jiawei, Shen, Tianchang, Wu, Zhangjie, Gao, Jun, Wang, Yue, Chen, Siheng, Chen, Mike, Fidler, Sanja, Huang, Jiahui
Previous methods for scene generation either suffer from limited scales or lack geometric and appearance Generating simulatable and controllable 3D scenes is an essential consistency along generated sequences. In contrast, task for a wide spectrum of applications, including we leverage the recent advancements in scalable 3D mixed reality, robotics, and the training and testing of autonomous representation and video models to achieve large dynamic vehicles (AV) [25, 33]. In particular, the requirements scene generation that allows flexible controls through HD of AV applications have introduced new challenges maps, vehicle bounding boxes, and text descriptions. First, for 3D generative models in driving scenarios, posing the we construct a map-conditioned sparse-voxel-based 3D following key desiderata: (1) fidelity and consistency, to generative model to unleash its power for unbounded voxel ensure that the generated scenes support photo-realistic rendering world generation. Then, we re-purpose a video model and while preserving consistent appearance and geometry ground it on the voxel world through a set of carefully designed for reliable and stable physics simulation; (2) largescale, pixel-aligned guidance buffers, synthesizing a consistent to generate scenes at map-level for traffic simulation; appearance. Finally, we propose a fast feed-forward and (3) controllability, to allow easy manipulation of the approach that employs both voxel and pixel branches to lift scene layout, appearance, and ego-car behaviors for curating the dynamic videos to dynamic 3D Gaussians with control-adversarial scenarios.
SpaceMesh: A Continuous Representation for Learning Manifold Surface Meshes
Shen, Tianchang, Li, Zhaoshuo, Law, Marc, Atzmon, Matan, Fidler, Sanja, Lucas, James, Gao, Jun, Sharp, Nicholas
Meshes are ubiquitous in visual computing and simulation, yet most existing machine learning techniques represent meshes only indirectly, e.g. as the level set of a scalar field or deformation of a template, or as a disordered triangle soup lacking local structure. This work presents a scheme to directly generate manifold, polygonal meshes of complex connectivity as the output of a neural network. Our key innovation is to define a continuous latent connectivity space at each mesh vertex, which implies the discrete mesh. In particular, our vertex embeddings generate cyclic neighbor relationships in a halfedge mesh representation, which gives a guarantee of edge-manifoldness and the ability to represent general polygonal meshes. This representation is well-suited to machine learning and stochastic optimization, without restriction on connectivity or topology. We first explore the basic properties of this representation, then use it to fit distributions of meshes from large datasets. The resulting models generate diverse meshes with tessellation structure learned from the dataset population, with concise details and high-quality mesh elements. In applications, this approach not only yields high-quality outputs from generative models, but also enables directly learning challenging geometry processing tasks such as mesh repair.
Flexible Isosurface Extraction for Gradient-Based Mesh Optimization
Shen, Tianchang, Munkberg, Jacob, Hasselgren, Jon, Yin, Kangxue, Wang, Zian, Chen, Wenzheng, Gojcic, Zan, Fidler, Sanja, Sharp, Nicholas, Gao, Jun
This work considers gradient-based mesh optimization, where we iteratively optimize for a 3D surface mesh by representing it as the isosurface of a scalar field, an increasingly common paradigm in applications including photogrammetry, generative modeling, and inverse physics. Existing implementations adapt classic isosurface extraction algorithms like Marching Cubes or Dual Contouring; these techniques were designed to extract meshes from fixed, known fields, and in the optimization setting they lack the degrees of freedom to represent high-quality feature-preserving meshes, or suffer from numerical instabilities. We introduce FlexiCubes, an isosurface representation specifically designed for optimizing an unknown mesh with respect to geometric, visual, or even physical objectives. Our main insight is to introduce additional carefully-chosen parameters into the representation, which allow local flexible adjustments to the extracted mesh geometry and connectivity. These parameters are updated along with the underlying scalar field via automatic differentiation when optimizing for a downstream task. We base our extraction scheme on Dual Marching Cubes for improved topological properties, and present extensions to optionally generate tetrahedral and hierarchically-adaptive meshes. Extensive experiments validate FlexiCubes on both synthetic benchmarks and real-world applications, showing that it offers significant improvements in mesh quality and geometric fidelity.