xeokit Streaming Loader

Loads chunked models from a manifest into a SceneModel and optional DataModel.

Large BIM and CAD models are often delivered as chunked geometry plus matching semantic data. ModelChunksLoader reads a manifest for those chunks and loads each one with the configured per-chunk loader.

Shape

classDiagram
    direction TB
    class ModelChunksLoader {
      +sceneModelLoader : ModelLoader
      +dataModelLoader? : ModelLoader
      +load(params)
    }
    class ModelChunksLoaderParams {
      +sceneModelLoader : ModelLoader
      +dataModelLoader? : ModelLoader
    }
    class ModelChunksManifestParams {
      +sceneModelMIMEType : string
      +sceneModelFiles    : string[]
      +dataModelFiles?    : string[]
    }
    class LoadModelChunksParams {
      +modelChunksManifest : ModelChunksManifestParams
      +baseDir             : string
      +sceneModel          : SceneModel
      +dataModel?          : DataModel
    }
    class SceneModel {
      <<scene>>
    }
    class DataModel {
      <<data>>
    }
    ModelChunksLoader ..> ModelChunksLoaderParams : constructor
    ModelChunksLoader ..> LoadModelChunksParams : load
    LoadModelChunksParams o-- ModelChunksManifestParams
    LoadModelChunksParams o-- SceneModel : writes
    LoadModelChunksParams o-- DataModel : writes

Manifest shape

The manifest is a small JSON file pairing geometry chunks with the matching semantic chunks:

{
    "sceneModelMIMEType": "arraybuffer",
    "sceneModelFiles": [
        "model.xgf",
        "model2.xgf",
        "model3.xgf"
    ],
    "dataModelFiles": [
        "model.json",
        "model2.json",
        "model3.json"
    ]
}
Copy

• sceneModelFiles lists the geometry chunks (XGF, glTF, …).
• dataModelFiles (optional) lists matching DataModel JSON chunks.
• sceneModelMIMEType chooses how chunks are fetched ("arraybuffer" for binary, "json" for text).

Features

• One call loads the whole model — pass the manifest, baseDir, and the target SceneModel + DataModel.
• Pluggable per-chunk loaders; pass an formats!XGFLoader | XGFLoader for geometry, DataModelImporter for semantics, or any other loader that implements ModelLoader.
• Geometry and semantics stay aligned — chunks share an ordering so the loader emits SceneObjects and DataObjects with matching ids.
• Resolves when loading finishes — the returned Promise settles once every chunk reaches its target model.

Installation

npm install @xeokit/sdk
Copy

Quick Start

1) Import the entry point

import { ModelChunksLoader } from "@xeokit/sdk/model/streaming";
import { XGFLoader }         from "@xeokit/sdk/formats/xgf";
import { DataModelImporter } from "@xeokit/sdk/formats/datamodel";
Copy

2) Construct with per-chunk loaders

const modelChunksLoader = new ModelChunksLoader({
  sceneModelLoader: new XGFLoader(),
  dataModelLoader:  new DataModelImporter()
});
Copy

3) Load a manifest

const manifest = await fetch("modelChunksManifest.json").then(r => r.json());

await modelChunksLoader.load({
  modelChunksManifest: manifest,
  baseDir: ".",
  sceneModel,
  dataModel
});
Copy