🤖 AI Summary
Existing methods struggle to efficiently generate high-quality, complete 3D assets suitable for multi-view simulation from sparse and heavily occluded real-world driving scenes. This work proposes a “reconstruct-then-generate” 3D latent diffusion model that first constructs a high-fidelity object latent space by integrating LiDAR and camera data through occlusion-aware neural rendering trained jointly across multiple scenes. A 3D latent diffusion model is then trained in this space to synthesize diverse assets with complete geometry and appearance. By uniquely combining occlusion-aware neural reconstruction with 3D latent diffusion generation, the method significantly outperforms existing approaches on real-world driving data, achieving superior completeness, diversity, and simulation readiness, thereby enabling large-scale autonomous driving simulation applications.
📝 Abstract
High-quality 3D assets for traffic participants are critical for multi-sensor simulation, which is essential for the safe end-to-end development of autonomy. Building assets from in-the-wild data is key for diversity and realism, but existing neural-rendering based reconstruction methods are slow and generate assets that render well only from viewpoints close to the original observations, limiting their usefulness in simulation. Recent diffusion-based generative models build complete and diverse assets, but perform poorly on in-the-wild driving scenes, where observed actors are captured under sparse and limited fields of view, and are partially occluded. In this work, we propose a 3D latent diffusion model that learns on in-the-wild LiDAR and camera data captured by a sensor platform and generates high-quality 3D assets with complete geometry and appearance. Key to our method is a "reconstruct-then-generate" approach that first leverages occlusion-aware neural rendering trained over multiple scenes to build a high-quality latent space for objects, and then trains a diffusion model that operates on the latent space. We show our method outperforms existing reconstruction and generation based methods, unlocking diverse and scalable content creation for simulation.