Papers › Top-Down Beats Bottom-Up in 3D Instance Segmentation

Top-Down Beats Bottom-Up in 3D Instance Segmentation

6 Feb 2023arXiv:2302.02871archive 2025-07-28

Maksim Kolodiazhnyi, Anna Vorontsova, Anton Konushin, Danila Rukhovich

Most 3D instance segmentation methods exploit a bottom-up strategy, typically including resource-exhaustive post-processing. For point grouping, bottom-up methods rely on prior assumptions about the objects in the form of hyperparameters, which are domain-specific and need to be carefully tuned. On the contrary, we address 3D instance segmentation with a TD3D: the pioneering cluster-free, fully-convolutional and entirely data-driven approach trained in an end-to-end manner. This is the first top-down method outperforming bottom-up approaches in 3D domain. With its straightforward pipeline, it demonstrates outstanding accuracy and generalization ability on the standard indoor benchmarks: ScanNet v2, its extension ScanNet200, and S3DIS, as well as on the aerial STPLS3D dataset. Besides, our method is much faster on inference than the current state-of-the-art grouping-based approaches: our flagship modification is 1.9x faster than the most accurate bottom-up method, while being more accurate, and our faster modification shows state-of-the-art accuracy running at 2.6x speed. Code is available at https://github.com/SamsungLabs/td3d .

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Tasks

3D Instance SegmentationInstance SegmentationSegmentationSemantic Segmentation

Results from the paper archive 2025-07-28

TaskDatasetModelMetricValueRank at snapshotLeaderboardReport
3D Instance Segmentation S3DIS TD3D AP@50 70.4 #5 of 21 Archive leaderboard report
3D Instance Segmentation S3DIS TD3D mAP 58.1 #5 of 21 Archive leaderboard report
3D Instance Segmentation STPLS3D TD3D AP 54.3 #3 of 9 Archive leaderboard report
3D Instance Segmentation STPLS3D TD3D AP50 69.8 #3 of 9 Archive leaderboard report
3D Instance Segmentation ScanNet(v2) TD3D mAP 48.9 #11 of 32 Archive leaderboard report
3D Instance Segmentation ScanNet(v2) TD3D mAP @ 50 75.1 #11 of 32 Archive leaderboard report
3D Instance Segmentation ScanNet(v2) TD3D mAP@25 87.5 #11 of 32 Archive leaderboard report

Ranks are positions in the archive's leaderboards as they stood at the 2025-07-28 snapshot. Results published since then are not among these rows, so a rank here is not a current standing.

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