Home - Jangmyun/copcesium GitHub Wiki

copcesium wiki

CesiumJS provider for real-time COPC (Cloud Optimized Point Cloud) streaming and rendering.

This wiki is the in-depth companion to the README. The README covers install and quick start; the wiki covers how the internals work, how to tune them, and how to get out of trouble.

Pages

  • Architecture — the three-layer pipeline (Data → Cache & Scheduler → Render) and how a node travels through it.
  • Options & Tuning — every option, what it trades off, how to tune for quality vs. memory vs. bandwidth, and the live styling API.
  • Coordinate Systems — WKT auto-detection, the proj4 fallback table, compound CRSes, and vertical units.
  • Converting to COPC — turning LAS/LAZ into .copc.laz with PDAL, untwine, or QGIS.
  • Troubleshooting — CORS, Range Requests, blank screens, misplaced clouds, and other common failures.
  • Third-Party Licenses — what's bundled into the published package, and under which licenses.

At a glance

  • Streaming, not loading — only the octree nodes the camera can see are fetched, over HTTP Range Requests.
  • Off the main thread — LAZ decompression and coordinate transforms run in a pool of reused Web Workers.
  • Screen-space-error LoD — point density matches what the camera can actually resolve, bounded by node and point budgets, with no flash of empty space mid-transition.
  • Prefetching — nodes just outside the view are loaded ahead of a pan, without delaying what's on screen.
  • Measurable — dataSource.stats reports bytes transferred against file size, plus per-stage fetch/decode/upload timings.
  • CRS-aware — auto-detects the source coordinate system from the file's own WKT metadata.
  • Live-tunable — sseThreshold, point size (pixelSize, pointSizeMode and its attenuation bounds), heightOffset, and the whole styling API (colorMode, opacity, classificationFilter, intensityRange) can be adjusted on a running data source with no reload.
  • Genuinely drop-in — a single self-contained .mjs; the Worker and its WASM are inlined at build time.

Links