Echo-3 is an AI world model by SpAItial that converts a few minutes of phone video into a photorealistic 3D environment at real-world scale. Users open the SpAItial app, walk slowly around a space, and Echo-3 reconstructs it as a Gaussian Splat scene with accurate dimensions. The resulting 3D world can be explored interactively, used to take measurements, and shared via a link that opens in any browser. It is designed to make high-fidelity spatial capture accessible without specialized hardware.