WorldCraft: Persistent Object-State Control in Camera-Navigable Video World Models

Recent video world models enable interactive camera navigation but provide limited control over individual objects. We study persistent object-state control in autoregressive video world models, where an object-trajectory action must remain effective across viewpoint changes, generation chunks, and intervals of temporary invisibility. This setting introduces an action-memory conflict because autoregressive memory records the last observed object state, whereas an intervening action may update that state off-screen. We present WorldCraft, the first camera-navigable autoregressive video world model to jointly compose camera navigation and object-trajectory control. Given a user-selected object and a 2D motion path, Normalized World Trajectory (NWT) anchors the path in a normalized world coordinate system and projects it into each camera view, producing a consistent object-action signal throughout the autoregressive rollout. Trajectory-Anchored State Persistence (TASP) combines persistent NWT guidance with selective memory refresh to maintain action-updated object states through off-screen intervals and re-entry. A pathway-selective LoRA introduces object control while retaining the pretrained camera controller. WorldCraft achieves accurate composable camera-object control and preserves camera fidelity. We further find that it maintains action-updated object states across extended intervals of complete target invisibility without off-screen trajectory supervision.