ThreeJs ThreeMF loader is blocking the UI while upzipping the 3MF file.

Description of the problem

ThreeJs ThreeMF loader is blocking the UI while upzipping the 3MF file.

try {
	zip = new JSZip( data ); // eslint-disable-line no-undef
} catch ( e ) {
	if ( e instanceof ReferenceError ) {
		console.error( 'THREE.3MFLoader: jszip missing and file is compressed.' );
		return null;
	}
}

According the the JSZip documenation I assume it would be better to unzip the container asynchronously not to block the UI.

Three.js version

• [x ] Dev
• r120
• …

Browser

• All of them
• Chrome
• Firefox
• Internet Explorer

OS

• All of them
• Windows
• macOS
• Linux
• Android
• iOS

Hardware Requirements (graphics card, VR Device, …)

[Mugen87]

After a closer performance analysis of 3MFLoader.parse(), the actual overhead does indeed not come from the unzip operation. DOMParser.parseFromString() as well as the processing of the XML document takes way more time than anything else. In webgl_loader_3mf_materials, unzipping takes 2.6 ms whereas the rest of parse() takes 1.85 seconds.

So similar to ColladaLoader, the actual overhead is produced by parsing and processing XML. Hence, marking this issue as a duplicate of #11746.

[donmccurdy]

Might be a good candidate for https://github.com/mrdoob/three.js/pull/19650? We could keep JSZip but move it to a worker.