HERO: Hierarchical Traversable 3D Scene Graphs for Embodied Navigation Among Movable Obstacles

TL;DR

HERO introduces a hierarchical 3D scene graph framework that models movable obstacles as traversable pathways, significantly improving navigation efficiency and reachability in complex environments for embodied agents.

Contribution

The paper presents HERO, a novel hierarchical 3D scene graph approach that redefines traversability by incorporating movable obstacles as pathways, enabling better reasoning and planning.

Findings

PL reduced by 35.1% in partially obstructed environments

SR increased by 79.4% in fully obstructed environments

Enhanced efficiency and reachability in complex scenes

Abstract

3D Scene Graphs (3DSGs) constitute a powerful representation of the physical world, distinguished by their abilities to explicitly model the complex spatial, semantic, and functional relationships between entities, rendering a foundational understanding that enables agents to interact intelligently with their environment and execute versatile behaviors. Embodied navigation, as a crucial component of such capabilities, leverages the compact and expressive nature of 3DSGs to enable long-horizon reasoning and planning in complex, large-scale environments. However, prior works rely on a static-world assumption, defining traversable space solely based on static spatial layouts and thereby treating interactable obstacles as non-traversable. This fundamental limitation severely undermines their effectiveness in real-world scenarios, leading to limited reachability, low efficiency, and inferior extensibility. To address these issues, we propose HERO, a novel framework for constructing Hierarchical Traversable 3DSGs, that redefines traversability by modeling operable obstacles as pathways, capturing their physical interactivity, functional semantics, and the scene's relational hierarchy. The results show that, relative to its baseline, HERO reduces PL by 35.1% in partially obstructed environments and increases SR by 79.4% in fully obstructed ones, demonstrating substantially higher efficiency and reachability.