NTH

Foundation4D: Towards a unified perception and reconstruction model for autonomous vehicles

AuthorsNVIDIA, :, Sérgio Agostinho, Maximilian Apodaca, Emmanuel Attia, Guillem Braso, George Dong, Ilya Fedorov, Michele Fenzi, Gang Huang, Jiahui Huang, Shengyu Huang, Bingxin Ke, Laura Leal-Taixé, Kuan-Ting Lee, Mingxuan Liu, Tian Liu, Tim Meinhardt, Aljoša Ošep, Naveen Kumar Rai, Kefei Ren, Cristiano Saltori, Keqiang Wu, Ning Xu, Fei Xue, Jin-Bey Yu, Lei Zhang, Qunjie Zhou

October 31, 2026 2 min read
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The one-line take

Foundation4D combines multi-camera driving video to estimate scene geometry, detect objects, map occupancy, and reconstruct scenes for simulation.

Key results

1,253
PAI–Foundation4D clips

Driving clips with dense depth and semantic occupancy annotations.

60.9
nuScenes detection mAP

Foundation4D result after benchmark-specific fine-tuning.

18.1
OpenOccupancy mIoU

Foundation4D semantic occupancy score.

1.2
Detection co-training gain

mAP points gained by co-training detection with geometry and occupancy.

13.4%
Camera-to-rig translation error reduction

Reduction from co-training geometry with detection versus geometry-only training.

4.3
NuRec workflow speedup

End-to-end lidarless reconstruction turnaround improvement.

What the paper found

NVIDIA’s Foundation4D combines driving perception and scene reconstruction in one feed-forward model. A shared DINOv2 ViT-L/14 backbone processes multi-camera video using factorized attention across views and time, while separate heads predict camera poses, metric depth, 3D objects, semantic occupancy, and renderable 3D Gaussians. For long recordings, pose-graph optimization aligns overlapping windows, and offline tracking links detections into object trajectories. The team also introduces PAI–Foundation4D, a benchmark with dense depth and occupancy annotations for 1,253 driving clips. After benchmark-specific fine-tuning, the model reaches 60.9 mAP on nuScenes and 18.1 mIoU on OpenOccupancy, leading the compared methods on those measures. Joint training helps across tasks: adding geometry and occupancy raises detection mAP by 1.2 points over detection-only training, while combining geometry with detection cuts camera-to-rig translation error by 13.4% versus geometry-only training. The predicted geometry and tracks also serve as priors for lidarless NuRec; the reported end-to-end reconstruction workflow runs 4.3× faster. The results show how one shared model can produce both structured scene understanding and inputs for simulation, while performance still depends on which tasks are trained together.

Original abstract

We introduce Foundation4D, a unified feed-forward model for geometry estimation, 3D detection, semantic occupancy, and Gaussian reconstruction from multi-camera driving video. A shared backbone uses factorized spatiotemporal attention to efficiently combine observations across cameras and time. Our video inference pipeline uses pose graph optimization to refine camera trajectories and assembles object tracks across input windows. We also develop a data annotation pipeline and release PAI-Foundation4D, a benchmark with dense depth and semantic occupancy labels for 1,253 driving clips. With benchmark-specific fine-tuning, Foundation4D achieves the lowest depth AbsRel on Waymo and nuScenes, the highest detection mAP on nuScenes, and the highest occupancy mIoU on OpenOccupancy among the compared methods. Our task-combination study shows benefits for both detection and geometry: co-training detection with geometry and occupancy improves top-class mAP by 1.2 points over detection-only training, while co-training geometry with detection reduces camera-to-rig translation error by $13.4\%$ relative to geometry-only training. We further use the predicted geometry and trajectories as priors for lidarless NuRec, supporting reconstruction of driving scenes for simulation.

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