Startups like Decart and Odyssey have released free demos, and Google’s Genie is still in limited research preview. Marble differs from these — and even World Labs’s own real-time model, RTFM — because it creates persistent, downloadable 3D environments rather than generating worlds on-the-fly as you explore. This, the company says, results in less morphing or inconsistency, and lets users export worlds as Gaussian splats, meshes or videos.