LASLoaderPlugin

Viewer plugin that loads lidar point cloud geometry from LAS files.

[Run this example]

Summary

• Loads LAS Formats up to v1.3 from both .las and .laz files. It does not support LAS v1.4.
• Loads lidar point cloud positions, colors and intensities.
• Supports 32 and 64-bit positions.
• Supports 8 and 16-bit color depths.
• Option to load every n points.
• Does not (yet) load point classifications.

Performance

If you need faster loading, consider pre-converting your LAS files to XKT format using xeokit-convert, then loading them with XKTLoaderPlugin.

Scene and metadata representation

When LASLoaderPlugin loads a LAS file, it creates two Entitys, a MetaModel and a MetaObject.

The first Entity represents the file as a model within the Viewer's Scene. To indicate that it represents a model, this Entity will have Entity#isModel set true and will be registered by Entity#id in Scene#models.

The second Entity represents the the point cloud itself, as an object within the Scene. To indicate that it represents an object, this Entity will have Entity#isObject set true and will be registered by Entity#id in Scene#objects.

The MetaModel registers the LAS file as a model within the Viewer's MetaScene. The MetaModel will be registered by MetaModel#id in MetaScene#metaModels .

Finally, the MetaObject registers the point cloud as an object within the MetaScene. The MetaObject will be registered by MetaObject#id in MetaScene#metaObjects.

Usage

In the example below we'll load the Autzen model from a LAS file. Once the model has loaded, we'll then find its MetaModel, and the MetaObject and Entity that represent its point cloud.

• [Run this example]

import {Viewer, LASLoaderPlugin} from "xeokit-sdk.es.js";

const viewer = new Viewer({
     canvasId: "myCanvas",
     transparent: true
});

viewer.camera.eye = [-2.56, 8.38, 8.27];
viewer.camera.look = [13.44, 3.31, -14.83];
viewer.camera.up = [0.10, 0.98, -0.14];

const lasLoader = new LASLoaderPlugin(viewer, {
    colorDepth: 8, // Default
    fp64: false,   // Default
    skip: 1        // Default
});

const modelEntity = lasLoader.load({
    id: "myModel",
    src: "../assets/models/las/autzen.laz"
});

modelEntity.on("loaded", () => {

     const metaModel = viewer.metaScene.metaModels[modelEntity.id];
     const pointCloudMetaObject = metaModel.rootMetaObject;

     const pointCloudEntity = viewer.scene.objects[pointCloudMetaObject.id];

     //...
});

Transforming

We have the option to rotate, scale and translate each LAS model as we load it.

In the example below, we'll scale our model to half its size, rotate it 90 degrees about its local X-axis, then position it at [1842022, 10, -5173301] within xeokit's world coordinate system.

const modelEntity = lasLoader.load({
     id: "myModel",
     src: "../assets/models/las/autzen.laz"
     rotation: [90,0,0],
     scale: [0.5, 0.5, 0.5],
     origin: [1842022, 10, -5173301]
});

Configuring a custom data source

By default, LASLoaderPlugin will load LAS files over HTTP.

In the example below, we'll customize the way LASLoaderPlugin loads the files by configuring it with our own data source object. For simplicity, our custom data source example also uses HTTP, using a couple of xeokit utility functions.

import {utils} from "xeokit-sdk.es.js";

class MyDataSource {

     constructor() {
     }

     // Gets the contents of the given LAS file in an arraybuffer
     getLAS(src, ok, error) {
         utils.loadArraybuffer(src,
             (arraybuffer) => {
                 ok(arraybuffer);
             },
             (errMsg) => {
                 error(errMsg);
             });
     }
}

const lasLoader = new LASLoaderPlugin(viewer, {
      dataSource: new MyDataSource()
});

const modelEntity = lasLoader.load({
     id: "myModel",
     src: "../assets/models/las/autzen.laz"
});

Showing a LAS/LAZ model in TreeViewPlugin

We can use the load() method's elementId parameter to make LASLoaderPlugin load the entire model into a single Entity that gets this ID.

In conjunction with that parameter, we can then use the load() method's metaModelJSON parameter to create a MetaModel that contains a MetaObject that corresponds to that Entity.

When we've done that, then xeokit's TreeViewPlugin is able to have a node that represents the model and controls the visibility of that Entity (ie. to control the visibility of the entire model).

The snippet below shows how this is done.

import {Viewer, LASLoaderPlugin, NavCubePlugin, TreeViewPlugin} from "../../dist/xeokit-sdk.es.js";

const viewer = new Viewer({
    canvasId: "myCanvas",
    transparent: true
});

new TreeViewPlugin(viewer, {
    containerElement: document.getElementById("treeViewContainer"),
    hierarchy: "containment"
});

const lasLoader = new LASLoaderPlugin(viewer);

const sceneModel = lasLoader.load({  // Creates a SceneModel with ID "myScanModel"
    id: "myScanModel",
    src: "../../assets/models/las/Nalls_Pumpkin_Hill.laz",
    rotation: [-90, 0, 0],

    entityId: "3toKckUfH2jBmd$7uhJHa4", // Creates an Entity with this ID

    metaModelJSON: { // Creates a MetaModel with ID "myScanModel"
        "metaObjects": [
            {
                "id": "3toKckUfH2jBmd$7uhJHa6", // Creates this MetaObject with this ID
                "name": "My Project",
                "type": "Default",
                "parent": null
            },
            {
                "id": "3toKckUfH2jBmd$7uhJHa4", // Creates this MetaObject with this ID
                "name": "My Scan",
                "type": "Default",
                "parent": "3toKckUfH2jBmd$7uhJHa6"
            }
        ]
    }
});