From Spatial to Actions: Grounding Vision-Language-Action Model in Spatial Foundation Priors

TL;DR

FALCON introduces a novel approach that incorporates rich 3D spatial priors into vision-language-action models, significantly improving spatial reasoning, transferability, and alignment for real-world tasks using RGB data alone.

Contribution

The paper presents FALCON, a new paradigm that injects 3D spatial tokens into the action head, leveraging spatial foundation models without retraining or architectural changes.

Findings

Achieves state-of-the-art performance across benchmarks.

Robust under clutter and spatial prompts.

Outperforms competitive baselines in real-world tasks.

Abstract

Existing vision-language-action (VLA) models act in 3D real-world but are typically built on 2D encoders, leaving a spatial reasoning gap that limits generalization and adaptability. Recent 3D integration techniques for VLAs either require specialized sensors and transfer poorly across modalities, or inject weak cues that lack geometry and degrade vision-language alignment. In this work, we introduce FALCON (From Spatial to Action), a novel paradigm that injects rich 3D spatial tokens into the action head. FALCON leverages spatial foundation models to deliver strong geometric priors from RGB alone, and includes an Embodied Spatial Model that can optionally fuse depth, or pose for higher fidelity when available, without retraining or architectural changes. To preserve language reasoning, spatial tokens are consumed by a Spatial-Enhanced Action Head rather than being concatenated into the vision-language backbone. These designs enable FALCON to address limitations in spatial representation, modality transferability, and alignment. In comprehensive evaluations across three simulation benchmarks and eleven real-world tasks, our proposed FALCON achieves state-of-the-art performance, consistently surpasses competitive baselines, and remains robust under clutter, spatial-prompt conditioning, and variations in object scale and height.