three.js/examples/jsm/csm/FrustumVertex.js

export default class FrustumVertex {

	constructor( x, y, z ) {

		this.x = x || 0;
		this.y = y || 0;
		this.z = z || 0;

	}

	fromLerp( v1, v2, amount ) {

		this.x = ( 1 - amount ) * v1.x + amount * v2.x;
		this.y = ( 1 - amount ) * v1.y + amount * v2.y;
		this.z = ( 1 - amount ) * v1.z + amount * v2.z;

		return this;

	}

}