OriGround: Orientation-Aware Neuro-Symbolic Zero-Shot 3D Visual Grounding

Haochen Li, Jiaxin Shi, Ruonan Liu, Luo Liufu


Abstract
Zero-shot 3D visual grounding (3DVG) aims to localize a referred object in a 3D scene without task-specific grounding supervision. Existing training-free methods commonly reason over object categories, centers, and bounding boxes, but these representations do not encode the local reference frames needed to interpret viewpoint-dependent expressions such as left of, behind, or facing the door. We propose OriGround, an orientation-aware neuro-symbolic framework that explicitly models object-centric orientations and infers observer viewpoints for zero-shot 3DVG. OriGround parses each query into a viewpoint-aware symbolic program, estimates object-centric orientation bases from multi-view observations, performs anchor- and observer-specific geometric relation scoring, and constructs a reference-frame-aligned visual prompt for final VLM-based disambiguation. On Nr3D, OriGround improves over the strongest training-free baseline by 8.4 points in overall accuracy, with larger gains of 8.9 points on hard queries and 5.6 points on view-dependent queries. On ScanRefer, OriGround further improves overall Acc@0.5 by 17.3 points over VLM-Grounder. Project page: https://origround.github.io/
Anthology ID:
2026.findings-emnlp.2237
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
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SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
47877–47897
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URL:
https://aclanthology.org/2026.findings-emnlp.2237/
DOI:
Bibkey:
Cite (ACL):
Haochen Li, Jiaxin Shi, Ruonan Liu, and Luo Liufu. 2026. OriGround: Orientation-Aware Neuro-Symbolic Zero-Shot 3D Visual Grounding. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 47877–47897, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
OriGround: Orientation-Aware Neuro-Symbolic Zero-Shot 3D Visual Grounding (Li et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.2237.pdf