SpatialAct: Probing Spatial Reasoning-to-Action Capabilities of VLM Agents in 3D Scenes

Fuente: arXiv
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Main Authors: Liu, Tianhui, Feng, Jie, Zheng, Zhiheng, Wang, Shengyuan, Guo, Yiming, Xi, Yanxin, Fan, Hangyu, Li, Yong, Hui, Pan
Format: Preprint
Published: 2026
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_version_ 1866917547722407936
author Liu, Tianhui
Feng, Jie
Zheng, Zhiheng
Wang, Shengyuan
Guo, Yiming
Xi, Yanxin
Fan, Hangyu
Li, Yong
Hui, Pan
author_facet Liu, Tianhui
Feng, Jie
Zheng, Zhiheng
Wang, Shengyuan
Guo, Yiming
Xi, Yanxin
Fan, Hangyu
Li, Yong
Hui, Pan
contents Humans can effortlessly perceive spatial layouts, form cognitive representations, reason about spatial relations, and translate such reasoning into actions in everyday 3D environments. Although recent vision-language models (VLMs) have shown promising performance on observation-conditioned spatial perception and reasoning tasks, it remains unclear whether they can build coherent spatial understanding, act upon it, and refine their actions through multi-turn feedback. To study this problem, we introduce \textbf{SpatialAct}, a simulator-grounded benchmark for probing \textit{action-conditioned spatial reasoning} in 3D scenes. Starting from the most challenging setting, Multi-turn Interactive Refinement, we further design its decomposed counterpart, Single-step Error Detection and Fix, together with five fundamental spatial ability tasks to diagnose the underlying causes of model failures. Experiments reveal a clear reasoning-to-action gap: current VLMs can perform well on isolated spatial reasoning tasks, but struggle to maintain coherent spatial beliefs and produce reliable actions during multi-turn feedback, substantially underperforming humans. These results suggest that current VLM agents still lack robust spatial state tracking under action-induced environment changes, even when low-level control is abstracted away.
format Preprint
id arxiv_https___arxiv_org_abs_2605_31148
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle SpatialAct: Probing Spatial Reasoning-to-Action Capabilities of VLM Agents in 3D Scenes
Liu, Tianhui
Feng, Jie
Zheng, Zhiheng
Wang, Shengyuan
Guo, Yiming
Xi, Yanxin
Fan, Hangyu
Li, Yong
Hui, Pan
Computer Vision and Pattern Recognition
Artificial Intelligence
Computation and Language
Humans can effortlessly perceive spatial layouts, form cognitive representations, reason about spatial relations, and translate such reasoning into actions in everyday 3D environments. Although recent vision-language models (VLMs) have shown promising performance on observation-conditioned spatial perception and reasoning tasks, it remains unclear whether they can build coherent spatial understanding, act upon it, and refine their actions through multi-turn feedback. To study this problem, we introduce \textbf{SpatialAct}, a simulator-grounded benchmark for probing \textit{action-conditioned spatial reasoning} in 3D scenes. Starting from the most challenging setting, Multi-turn Interactive Refinement, we further design its decomposed counterpart, Single-step Error Detection and Fix, together with five fundamental spatial ability tasks to diagnose the underlying causes of model failures. Experiments reveal a clear reasoning-to-action gap: current VLMs can perform well on isolated spatial reasoning tasks, but struggle to maintain coherent spatial beliefs and produce reliable actions during multi-turn feedback, substantially underperforming humans. These results suggest that current VLM agents still lack robust spatial state tracking under action-induced environment changes, even when low-level control is abstracted away.
title SpatialAct: Probing Spatial Reasoning-to-Action Capabilities of VLM Agents in 3D Scenes
topic Computer Vision and Pattern Recognition
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2605.31148