StateFlow: Building, Evolving, and Accessing 3D World States for Previsualization

Previsualization bridges ideas and production in film, games, architecture, and urban design by letting creators iteratively refine scenes, actions, cameras, and spatial-temporal dynamics. Existing generative methods instead jointly control these factors through one-shot image or video synthesis, providing limited support for local editing, long-horizon evolution, and scene revisitation. Revisiting and selectively editing interacting elements requires an explicit, persistent world state that separates scene structure, evolution, and observation. We present **StateFlow**, a state-centric framework built around an editable 3D world with three components. State Construction generates complementary front-view and bird's-eye references, matches their object evidence, and lifts the matched objects into a spatially grounded initial 3D state under geometric and physical priors. State Evolution converts user intent into selective state transitions while preserving unaffected content and accumulated world history. State Access closes the loop between camera proposals and rendered feedback to obtain feasible views of the evolving world. Experiments on complex dynamic scenes demonstrate spatial-temporal consistency across long sequences and multi-object interactions, together with high-quality video creation and game-like prototyping.