OctWorld: Long-Range World-Consistent Video Generation with Octree-based 3D Mapping

We present OctWorld, a video diffusion framework with 3Dmemory for generating explorable, world-consistent, and high-fidelity vi-sual scenes. Given a single image, OctWorld enables stable autoregressiveworld generation along user-specified camera trajectories. We focus onthe problem of long spatial range generation, characterized by long cam-era path and wide viewing angle coverage, where maintaining spatialconsistency – particularly when revisiting previously generated regions –becomes challenging. To address this, we first build upon a pretrained au-toregressive video diffusion model that supports longer-horizon contextmodeling. We adapt this model to RGB-D generation and introduce adepth normalization scheme for inter-chunk consistency. Next, and moreimportantly, we propose an extensible and spatially-adaptive 3D memory,termed OctMap. OctMap constructs a global 3D representation of thegenerated scene by progressively fusing the generated RGB-D frames.To accommodate diverse scene scales in the open world setting, it ap-plies adaptive spatial resolution dynamically determined by image evi-dence with a sparse octree hierarchy, which preserves effective geometricand appearance details while maintaining low memory overhead. Experi-ments demonstrate that OctWorld can generate long-range and spatiallyconsistent videos, outperforming prior methods on existing benchmarksas well as in longer-range generation cases.