SpatialGuard: Harness-Guided Verifiable Spatial Reasoning for Text-to-Image Generation

Ziyun Qian, Zizhi Chen, Yizhou Liu, Mingyang Sun, Dingkang Yang, Lihua Zhang


Abstract
Complex 3D spatial text to image generation requires models to convert natural language into stable visual geometry, not merely semantic appearance. Existing prompt-driven or layout-conditioned methods improve controllability, but often lack an optimizable and verifiable spatial intermediary before visual sampling. As a result, object relations, occlusion, visibility, and camera constraints can decay during multi-round generation. This paper presents SpatialGuard, a structured layout-guided framework for complex 3D spatial text-to-image generation. SpatialGuard parses prompts into image synthesis-oriented 3D layouts through a Spatial Layout Architect, realizes them as visual conditions and candidate images through a Visual Realizer, and uses a Visual Alignment Critic to validate consistency among prompt, layout, and image. To keep constraints stable across iterations, SpatialGuard introduces a Layout Harness that organizes rule constraints, tool invocation, shared knowledge, and feedback loops around the editable layout state. This design turns complex spatial generation from implicit prompt following into a verifiable process of planning, realization, validation, and repair. Comprehensive experiments show that SpatialGuard achieves state-of-the-art performance in complex 3D spatial layout generation and improves spatial faithfulness over existing text-to-image and layout control baselines.
Anthology ID:
2026.emnlp-main.653
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
15022–15032
Language:
URL:
https://aclanthology.org/2026.emnlp-main.653/
DOI:
Bibkey:
Cite (ACL):
Ziyun Qian, Zizhi Chen, Yizhou Liu, Mingyang Sun, Dingkang Yang, and Lihua Zhang. 2026. SpatialGuard: Harness-Guided Verifiable Spatial Reasoning for Text-to-Image Generation. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 15022–15032, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
SpatialGuard: Harness-Guided Verifiable Spatial Reasoning for Text-to-Image Generation (Qian et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.653.pdf