4DGS360: 360° Gaussian Reconstruction of Dynamic Objects from a Single Video

We introduce 4DGS360, a di!usion-free framework for 360→dynamic object reconstruction from casual monocular video. Existingmethods often fail to reconstruct consistent 360→ geometry, as their heavyreliance on 2D-native priors causes initial points to overfit to visible sur-face in each training view. 4DGS360 addresses this challenge through anadvanced 3D-native initialization that mitigates the geometric ambigu-ity of occluded regions. Our proposed 3D tracker, AnchorTAP3D, pro-duces reinforced 3D point trajectories by leveraging confident 2D trackpoints as anchors, suppressing drift and providing reliable initializationthat preserves geometry in occluded regions. This initialization, com-bined with optimization, yields coherent 360→ 4D reconstructions. Wefurther present iPhone360, a new benchmark where test cameras areplaced up to 135→ apart from training views, enabling 360→ evaluationthat existing datasets cannot provide. Experiments show that 4DGS360achieves state-of-the-art performance on the iPhone360, iPhone, andDAVIS datasets, both qualitatively and quantitatively. Project websiteat https://jaewon040.github.io/4dgs360/