Temporally Smooth Mesh Extraction for Procedural Scenes with Long-Range Camera Trajectories using Spacetime Octrees

2025-09-16

AI Summary

To address temporal and spatial inconsistencies (e.g., popping artifacts) and high computational overhead in procedural scene mesh extraction under long camera trajectories, this paper proposes a spatiotemporally consistent 4D mesh extraction method. Our core contribution is the first introduction of a binary spatiotemporal octree—a 4D hierarchical structure that jointly encodes procedural occupancy evaluation and spatial partitioning within the four-dimensional spacetime domain, enabling adaptive, incremental mesh generation. Leveraging temporal coherence, the octree dynamically prunes and reuses nodes across frames, eliminating frame-wise independent reconstruction and its associated visual discontinuities, while avoiding the memory and computational bottlenecks of static full-scene meshing. Experiments demonstrate that our method significantly improves inter-frame geometric consistency at comparable computational cost, outperforming existing baselines. Its efficiency and robustness are validated in large-scale dynamic scenarios, such as forest navigation.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Knowledge Representation and Reasoning: Geometric, Spatial, and Temporal Reasoning
• Data Mining & Knowledge Management: Mining of Spatial, Temporal or Spatio-Temporal Data

Application Category

• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs
• Systems and Infrastructure for Web, Mobile and WoT: Data management and stream processing for Web, mobile and wireless applications
• Security and Privacy: Data transparency and provenance

Abstract

The procedural occupancy function is a flexible and compact representation for creating 3D scenes. For rasterization and other tasks, it is often necessary to extract a mesh that represents the shape. Unbounded scenes with long-range camera trajectories, such as flying through a forest, pose a unique challenge for mesh extraction. A single static mesh representing all the geometric detail necessary for the full camera path can be prohibitively large. Therefore, independent meshes can be extracted for different camera views, but this approach may lead to popping artifacts during transitions. We propose a temporally coherent method for extracting meshes suitable for long-range camera trajectories in unbounded scenes represented by an occupancy function. The key idea is to perform 4D mesh extraction using a new spacetime tree structure called a binary-octree. Experiments show that, compared to existing baseline methods, our method offers superior visual consistency at a comparable cost. The code and the supplementary video for this paper are available at https://github.com/princeton-vl/BinocMesher.

Problem

• Extracting temporally smooth meshes for long camera paths
• Avoiding popping artifacts in unbounded procedural scenes
• Managing geometric detail across extended camera trajectories

Innovation

• Spacetime octree structure for 4D extraction
• Binary-octree enables temporally coherent meshing
• Occupancy function representation for unbounded scenes