RADLoader and RADSourceLoader

RADLoader parses Spark .rad metadata. RADSourceLoader creates a runtime source for range-fetching Spark .rad headers, RADC chunks, and decoded chunk tables.

Property	Value
File format	RAD
Extensions	.rad
Worker	No
Input type	ArrayBuffer, URL, or Blob
Output	RAD metadata or RADSource

Usage

Use RADSourceLoader when working with remote LoD assets:

import {load} from '@loaders.gl/core';
import {RADSourceLoader} from '@loaders.gl/splats';

const source = await load(url, RADSourceLoader);
const metadata = await source.getMetadata();
const firstChunk = await source.getChunk(0);
const firstChunkTable = await source.getChunkTable(0);

for await (const chunkTable of source.getChunkTables({
  maxChunks: 8,
  pruneLoadedLoDParents: true
})) {
  // Append each decoded chunk table to a renderer-owned page cache.
}

For full buffers, RADLoader returns just the top-level metadata:

import {parse} from '@loaders.gl/core';
import {RADLoader} from '@loaders.gl/splats';

const metadata = await parse(arrayBuffer, RADLoader);

Format Support

RADLoader and RADSourceLoader support Spark RAD version 1 files with type: 'gsplat'. The source understands:

• top-level RAD0 metadata headers
• inline RADC chunks stored after the RAD header
• sidecar chunk filenames relative to the RAD URL
• RADC chunk metadata headers
• chunk range fetching through HTTP Range requests
• RADC payload decoding for centers, alpha, RGB, scales, orientations, LoD child arrays, and optional spherical harmonics
• Mesh Arrow table construction for individual chunks

RAD is a paged LoD format, so exact Spark-style rendering still requires a renderer to drive page selection, LoD tree traversal, and GPU residency. The source exposes chunk decoding so renderers and examples can bridge RAD pages into the standard loaders.gl Gaussian splat Arrow table shape.

Options

Option	Type	Default	Description
rad.headers	object	undefined	Request headers forwarded to RAD and RADC fetches.
rad.withCredentials	boolean	false	Includes credentials for remote RAD and RADC fetches.
rad.headerByteLengths	number[]	[65536, 262144, 1048576]	Header probe sizes used while range-fetching remote RAD metadata.
pruneLoadedLoDParents	boolean	false	When iterating chunk tables, removes parent LoD splats whose children are included in the loaded chunk range.
radChunk.includeLoDTree	boolean	true	Keeps decoded child_count and child_start arrays in chunk loaderData.
radChunk.includeSphericalHarmonics	boolean	false	Adds decoded SH rest coefficients to chunk Arrow tables.