BaseImporterPlugin

Source Code — API Reference

Abstract base plugin for file importers. Subclasses provide an Importer instance that defines the supported file extensions, MIME types, and loader class. When the plugin is added to the viewer, the importer is registered with the AssetManager's import pipeline. When removed, it is unregistered.

Creating a Custom Importer Plugin

A subclass needs two things — a PluginType and an _importer:

import {BaseImporterPlugin} from 'threepipe'
import {Importer} from 'threepipe'
import {MyFormatLoader} from './MyFormatLoader'

export class MyFormatPlugin extends BaseImporterPlugin {
    public static readonly PluginType = 'MyFormatPlugin'

    protected _importer = new Importer(
        MyFormatLoader,     // Loader class (extends three.js Loader)
        ['myf', 'myformat'],// Supported file extensions
        ['model/myformat'], // Supported MIME types
        false               // root: true if this is a primary scene format
    )
}

The Importer Constructor

new Importer(cls, ext, mime, root, onCtor?)

Parameter	Type	Description
cls	Class<Loader>	The loader class (must extend three.js Loader)
ext	string[] | () => string[]	Supported file extensions (lowercase). Can be a function for dynamic evaluation.
mime	string[]	Supported MIME types (lowercase)
root	boolean	Whether files of this type are "root" files — when importing folders/zips, only root files are loaded if any exist; non-root files are loaded only if no root files are found
onCtor	callback (optional)	Hook called after loader construction for setup (e.g., WASM paths, extensions)

Adding a Transform

When the raw loader output needs conversion (e.g., BufferGeometry to Mesh), use an anonymous inline class with a transform method:

import {ILoader} from 'threepipe'

protected _importer = new Importer(class extends STLLoader implements ILoader {
    transform(res: BufferGeometry): Mesh | undefined {
        if (!res) return undefined
        return new Mesh(res, new PhysicalMaterial({
            color: 0x888888,
            metalness: 0.5,
        }))
    }
}, ['stl'], ['model/stl'], false)

Properties

Property	Type	Description
_importer	Importer (abstract)	The importer instance subclasses must provide
toJSON	null	Serialization disabled — importer plugins represent capability, not state

Lifecycle

onAdded(viewer): Registers _importer into viewer.assetManager.importer.addImporter()

onRemove(viewer): Unregisters via viewer.assetManager.importer.removeImporter()

dispose(): No-op. Override in subclasses if cleanup is needed.

Built-in Subclasses

Core Package

Plugin	Extensions	Root	Notes
Rhino3dmLoadPlugin	.3dm	yes	Configurable UI properties
PLYLoadPlugin	.ply	no	Wraps geometry in Mesh
STLLoadPlugin	.stl	no	Wraps geometry in Mesh
KTX2LoadPlugin	.ktx2	no	WASM transcoder setup
KTXLoadPlugin	.ktx	no	Simplest subclass
USDZLoadPlugin	.usdz, .usda	no	Custom parse for USDA

External Packages

• @threepipe/plugins-extra-importers — 14 additional formats: 3DS, 3MF, Collada, AMF, GCode, BVH, VOX, MDD, PCD, Tilt, VRML, LDraw, VTK, XYZ
• @threepipe/plugin-blend-importer — Blender .blend files
• @threepipe/plugin-3d-tiles-renderer — B3DM, CMPT, PNTS, I3DM, DZI, slippy map tiles

The Simplest Subclass

KTXLoadPlugin:

import {BaseImporterPlugin} from '../base/BaseImporterPlugin'
import {Importer} from '../../assetmanager'
import {KTXLoader} from 'three/examples/jsm/loaders/KTXLoader.js'

export class KTXLoadPlugin extends BaseImporterPlugin {
    public static readonly PluginType = 'KTXLoadPlugin'
    protected _importer = new Importer(KTXLoader, ['ktx'], ['image/ktx'], false)
}

Related

• Loading Files — Guide on loading assets in threepipe