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Main Authors: Wang, Xinyi, Yang, Xun, Xu, Yanlong, Wu, Yuchen, Li, Zhen, Zhao, Na
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2511.10017
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author Wang, Xinyi
Yang, Xun
Xu, Yanlong
Wu, Yuchen
Li, Zhen
Zhao, Na
author_facet Wang, Xinyi
Yang, Xun
Xu, Yanlong
Wu, Yuchen
Li, Zhen
Zhao, Na
contents Effective human-agent collaboration in physical environments requires understanding not only what to act upon, but also where the actionable elements are and how to interact with them. Existing approaches often operate at the object level or disjointedly handle fine-grained affordance reasoning, lacking coherent, instruction-driven grounding and reasoning. In this work, we introduce a new task: Fine-grained 3D Embodied Reasoning, which requires an agent to predict, for each referenced affordance element in a 3D scene, a structured triplet comprising its spatial location, motion type, and motion axis, based on a task instruction. To solve this task, we propose AffordBot, a novel framework that integrates Multimodal Large Language Models (MLLMs) with a tailored chain-of-thought (CoT) reasoning paradigm. To bridge the gap between 3D input and 2D-compatible MLLMs, we render surround-view images of the scene and project 3D element candidates into these views, forming a rich visual representation aligned with the scene geometry. Our CoT pipeline begins with an active perception stage, prompting the MLLM to select the most informative viewpoint based on the instruction, before proceeding with step-by-step reasoning to localize affordance elements and infer plausible interaction motions. Evaluated on the SceneFun3D dataset, AffordBot achieves state-of-the-art performance, demonstrating strong generalization and physically grounded reasoning with only 3D point cloud input and MLLMs.
format Preprint
id arxiv_https___arxiv_org_abs_2511_10017
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle AffordBot: 3D Fine-grained Embodied Reasoning via Multimodal Large Language Models
Wang, Xinyi
Yang, Xun
Xu, Yanlong
Wu, Yuchen
Li, Zhen
Zhao, Na
Computer Vision and Pattern Recognition
Effective human-agent collaboration in physical environments requires understanding not only what to act upon, but also where the actionable elements are and how to interact with them. Existing approaches often operate at the object level or disjointedly handle fine-grained affordance reasoning, lacking coherent, instruction-driven grounding and reasoning. In this work, we introduce a new task: Fine-grained 3D Embodied Reasoning, which requires an agent to predict, for each referenced affordance element in a 3D scene, a structured triplet comprising its spatial location, motion type, and motion axis, based on a task instruction. To solve this task, we propose AffordBot, a novel framework that integrates Multimodal Large Language Models (MLLMs) with a tailored chain-of-thought (CoT) reasoning paradigm. To bridge the gap between 3D input and 2D-compatible MLLMs, we render surround-view images of the scene and project 3D element candidates into these views, forming a rich visual representation aligned with the scene geometry. Our CoT pipeline begins with an active perception stage, prompting the MLLM to select the most informative viewpoint based on the instruction, before proceeding with step-by-step reasoning to localize affordance elements and infer plausible interaction motions. Evaluated on the SceneFun3D dataset, AffordBot achieves state-of-the-art performance, demonstrating strong generalization and physically grounded reasoning with only 3D point cloud input and MLLMs.
title AffordBot: 3D Fine-grained Embodied Reasoning via Multimodal Large Language Models
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2511.10017