ViPlan: A Benchmark for Visual Planning with Symbolic Predicates and Vision-Language Models

Matteo Merler, Nicola Dainese, Minttu Alakuijala, Giovanni Bonetta, Pietro Ferrazzi, Yu Tian, Bernardo Magnini, Pekka Marttinen


Abstract
Integrating Large Language Models with symbolic planners is a promising direction for obtaining verifiable and grounded plans, with recent works extending this idea to visual domains using Vision-Language Models (VLMs). However, a rigorous comparison with methods that plan directly with VLMs is missing, due to a lack of visual benchmarks that support symbolic planning. We present ViPlan, the first open-source benchmark for comparing VLM-grounded symbolic approaches (VLM-as-grounder) with direct VLM planning methods (VLM-as-planner). ViPlan introduces a series of increasingly challenging tasks in two visual domains: a visual variant of the classic Blocksworld planning problem and a simulated household robotics environment. We find VLM-as-grounder methods to outperform direct VLM planning in Blocksworld (solving 46% of the tasks against 9%), where image grounding is both crucial and accurate. However, in the household robotics tasks, where linguistic knowledge helps, VLM-as-planner methods are greatly superior to VLM-as-grounder approaches (solving 34% of the tasks against 5%), which are hindered by partial observability. Thus, ViPlan domains capture fundamental shortcomings of both planning approaches, which we further diagnose with a qualitative failure analysis. Finally, across methods, we observe no consistent benefit from Chain-of-Thought prompting, suggesting persistent limitations in current VLMs’ visual reasoning abilities.
Anthology ID:
2026.findings-emnlp.1017
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:
21469–21516
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URL:
https://aclanthology.org/2026.findings-emnlp.1017/
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Cite (ACL):
Matteo Merler, Nicola Dainese, Minttu Alakuijala, Giovanni Bonetta, Pietro Ferrazzi, Yu Tian, Bernardo Magnini, and Pekka Marttinen. 2026. ViPlan: A Benchmark for Visual Planning with Symbolic Predicates and Vision-Language Models. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 21469–21516, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
ViPlan: A Benchmark for Visual Planning with Symbolic Predicates and Vision-Language Models (Merler et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1017.pdf