@xeokit/xeokit-xkt-utils

xeokit-xkt-utils

Use xeokit-xkt-utils to:

Convert BIM and AEC models into XKT files for super fast loading into xeokit
Generate XKT files with JavaScript

View this XKT model

Contents

Introduction
Acknowledgements
Resources
Features
Installing
Components
Using ```convert2xkt```

+ [Converting an IFC file into an XKT file on the command line](#converting-an-ifc-file-into-an-xkt-file-on-the-command-line)
+ [Converting an IFC file into an XKT file in Node.js](#converting-an-ifc-file-into-an-xkt-file-in-nodejs)
+ [Converting IFC file data into XKT data in Node.js](#converting-ifc-file-data-into-xkt-data-in-nodejs)

Using ```XKTModel```

+ [Programmatically Building an XKT File](#programmatically-building-an-xkt-file)
+ [Serializing the XKTModel to an ArrayBuffer](#serializing-the-xktmodel-to-an-arraybuffer)
+ [Loading the ArrayBuffer into a Viewer](#loading-the-arraybuffer-into-a-viewer)
+ [Loading IFC into an XKTModel](#loading-ifc-into-an-xktmodel)
+ [Loading glTF into an XKTModel](#loading-gltf-into-an-xktmodel)
+ [Loading STL into an XKTModel](#loading-stl-into-an-xktmodel)

Building

+ [Building Binaries](#building-binaries)
+ [Building Tests](#building-tests)

---

Introduction

```xeokit-xkt-utils``` provides the means to convert 3D BIM and AEC models into XKT files for super fast loading into xeokit, along with programming tools to generate XKT files with JavaScript on Node.js.
The XKT format compresses large double-precision models to a compact payload that loads quickly over the Web into a xeokit viewer running in the browser. We can use xeokit-xkt-utils to convert several source formats into XKT, such as IFC, glTF, 3DXML and CityJSON.

Acknowledgements

Our thanks to the authors of these open source libraries, which we use internally within ```xeokit-xkt-utils```:

loaders.gl - Copyright (C) 2015 Uber Technologies,

Inc. (MIT License)

Pako - Copyright (C) 2014-2017 by Vitaly Puzrin and Andrei

Tuputcyn (MIT License)

zip.js - Copyright (C) 2021 Gildas

Lormeau (BSD 3-Clause License)

earcut - Copyright (C) 2016,

Mapbox (ISC License)

web-ifc - Copyright (C) 2020-2021 web-ifc contributors (Mozilla Public License

Version 2.0)

Resources

Features

A Node-based CLI tool to convert various 3D model formats to XKT files.
A JavaScript toolkit of components for loading, generating and saving XKT files.

Installing

````bash npm i @xeokit/xeokit-xkt-utils ````

Components

The table below lists the components provided by ```xeokit-xkt-utils```.
At the center of the toolkit, we've got the converter tool, provided as both a Node.js function and CLI executable.
Bundled with the converter, we've got the XKT document model, a bunch of loaders for different formats, and a function to serialize the document model to a BLOB. We use these components within the converter tool, and also provide them as part of the public API for extensibility.
| Component | Description | | --- | --- | | convert2xkt (function)
convert2xkt (Node script)| A Node-based JavaScript function and CLI tool that converts various AEC model formats into xeokit's native, super-fast-loading XKT format. | | XKTModel | A JavaScript document model that represents the contents of an XKT file in memory. Using this, we can programmatically build a document model in JavaScript, adding geometries, materials, objects etc, then serialize it to an XKT file. | | parseIFCIntoXKTModel | Parses IFC data into an ```XKTModel``` | | parseGLTFIntoXKTModel | Parses glTF into an ```XKTModel``` | | parse3DXMLIntoXKTModel | Parses 3DXML into an ```XKTModel``` | | parseCityJSONIntoXKTModel | Parses CityJSON into an ```XKTModel``` | | parseLASIntoXKTModel | Parses LAS and LAZ into an ```XKTModel``` | | parseSTLIntoXKTModel | Parses STL into an ```XKTModel``` | | writeXKTModelToArrayBuffer | Serializes an ```XKTModel``` to an XKT file |

Using ```convert2xkt```

The ```convert2xkt``` tool converts various model formats into xeokit's native XKT format, which is designed to load super fast over the Web into a xeokit viewer. We provide this tool as both a CLI script() and as a function to use within our own Node scripts.
````bash node convert2xkt.js -h
Usage: convert2xkt options
Options:

-v, --version            output the version number
-s, --source [file]      path to source file
-f, --format [string]    source file format (optional); supported formats are gltf, ifc, laz, las, pcd, ply, stl and cityjson
-m, --metamodel [file]   path to source metamodel JSON file (optional)
-o, --output [file]      path to target .xkt file; creates directories on path automatically if not existing
-l, --log                enable logging
-h, --help               output usage information

````

Converting an IFC file into an XKT file on the command line

Let's use the convert2xkt Node script to convert an IFC file to XKT on the command line.
````bash node convert2xkt.js -s rmeadvancedsampleproject.ifc -o rmeadvancedsampleproject.ifc.xkt -l
Reading input file: rmeadvancedsampleproject.ifc Input file size: 35309.94 kB Converting... Converted objects: 6442 Converted geometries: 3897 Writing XKT file: rmeadvancedsampleproject.ifc.xkt XKT version: 9 XKT size: 1632.98 kB Compression ratio: 21.62 Conversion time: 54.41 s ````

Viewing the XKT file with xeokit

Now that we've got an XKT file, we can now view it in the browser using a xeokit Viewer configured with an XKTLoaderPlugin .
````javascript import {Viewer, XKTLoaderPlugin} from

"https://cdn.jsdelivr.net/npm/@xeokit/xeokit-sdk@1/dist/xeokit-sdk.es.min.js";

const viewer = new Viewer({

canvasId: "myCanvas"

});
const xktLoader = new XKTLoaderPlugin(viewer);
const modelNode = xktLoader.load({

id: "myModel",
src: "./rme_sample_project.ifc.xkt"

}); ````

Converting an IFC file into an XKT file in Node.js

We can use the convert2xkt function from within our Nodejs scripts to programmatically convert files to XKT.
This is awesome for automated model conversion, and our performance test suite.
````javascript const convert2xkt = require("@xeokit/xeokit-xkt-utils/dist/convert2xkt.cjs.js");
convert2xkt({

source: "rme_advanced_sample_project.ifc",
output: "rme_advanced_sample_project.ifc.xkt",
log: (msg) => {
    console.log(msg)
}

}).then(() => {

console.log("Converted.");

}, (errMsg) => {

console.error("Conversion failed: " + errMsg)

}); ````

Converting IFC file data into XKT data in Node.js

When using the convert2xkt function in our Node scripts, we can manage all file data in memory.
This is great for when we want more control over where we read and write the files.
````javascript const convert2xkt = require("@xeokit/xeokit-xkt-utils/dist/convert2xkt.cjs.js"); const fs = require('fs');
convert2xkt({

sourceData: fs.readFileSync("rme_advanced_sample_project.ifc"),
outputXKT: (xktData) => {
    fs.writeFileSync("rme_advanced_sample_project.ifc.xkt")
}

}).then(() => {

console.log("Converted.");

}, (errMsg) => {

console.error("Conversion failed: " + errMsg)

}); ````

Using ```XKTModel```

```XKTModel``` is a JavaScript class that represents the contents of an XKT file in memory.
It's a sort of XKT document model, with methods to build 3D objects within it, functions to import various model formats, and a function to serialize it to an XKT file.
We can use these tools to:

programmatically XKT files,
combine multiple models into an XKT file, from different formats,
develop custom XKT converters, and
extend ```convert2xkt``` to support more formats.

Programmatically Building an XKT File

To demonstrate the API, let's use ```XKTModel``` 's builder methods to programmatically build a model that resembles the screenshot below. Then we'll serialize the ```XKTModel``` to an ```ArrayBuffer```, which we'll finally load that into a xeokit ```Viewer``` using ```XKTLoaderPlugin``` .
We'll code this example to run in the browser, using the ES module in xeokit-xkt-utils.es.js. We could also code it to run on node, using the CommonJS module in xeokit-xkt-utils.cjs.js.
XKTModel Example

````javascript const {

XKTModel,
parseGLTFIntoXKTModel,
writeXKTModelToArrayBuffer

} = require("@xeokit/xeokit-xkt-utils/dist/xeokit-xkt-utils.cjs.js"); const fs = require('fs');
const xktModel = new XKTModel();
// Create metamodel - this part is optional
// Create property sets to hold info about the model
xktModel.createPropertySet({

propertySetId: "tableTopPropSet",
propertySetType: "Default",
propertySetName: "Table Top",
properties: [
    {
        id: "tableTopMaterial",
        type: "Default",
        name: "Table top material",
        value: "Marble"
    },
    {
        id: "tableTopDimensions",
        type: "Default",
        name: "Table top dimensions",
        value: "90x90x3 cm"
    }
]

});
xktModel.createPropertySet({

propertySetId: "tableLegPropSet",
propertySetType: "Default",
propertySetName: "Table Leg",
properties: [
    {
        id: "tableLegMaterial",
        type: "Default",
        name: "Table leg material",
        value: "Pine"
    },
    {
        id: "tableLegDimensions",
        type: "Default",
        name: "Table leg dimensions",
        value: "5x5x50 cm"
    }
]

});
// Create a hierarchy of metaobjects to describe the structure of the model
xktModel.createMetaObject({ // Root XKTMetaObject, has no XKTEntity

metaObjectId: "table",
metaObjectName: "The Table",
metaObjectType: "furniture"