three.js/examples/js/curves/NURBSSurface.js

( function () {

	/**
 * NURBS surface object
 *
 * Implementation is based on (x, y [, z=0 [, w=1]]) control points with w=weight.
 **/

	var NURBSSurface = function ( degree1, degree2, knots1, knots2
		/* arrays of reals */
		, controlPoints
		/* array^2 of Vector(2|3|4) */
	) {

		this.degree1 = degree1;
		this.degree2 = degree2;
		this.knots1 = knots1;
		this.knots2 = knots2;
		this.controlPoints = [];
		var len1 = knots1.length - degree1 - 1;
		var len2 = knots2.length - degree2 - 1; // ensure THREE.Vector4 for control points

		for ( var i = 0; i < len1; ++ i ) {

			this.controlPoints[ i ] = [];

			for ( var j = 0; j < len2; ++ j ) {

				var point = controlPoints[ i ][ j ];
				this.controlPoints[ i ][ j ] = new THREE.Vector4( point.x, point.y, point.z, point.w );

			}

		}

	};

	NURBSSurface.prototype = {
		constructor: NURBSSurface,
		getPoint: function ( t1, t2, target ) {

			var u = this.knots1[ 0 ] + t1 * ( this.knots1[ this.knots1.length - 1 ] - this.knots1[ 0 ] ); // linear mapping t1->u

			var v = this.knots2[ 0 ] + t2 * ( this.knots2[ this.knots2.length - 1 ] - this.knots2[ 0 ] ); // linear mapping t2->u

			THREE.NURBSUtils.calcSurfacePoint( this.degree1, this.degree2, this.knots1, this.knots2, this.controlPoints, u, v, target );

		}
	};

	THREE.NURBSSurface = NURBSSurface;

} )();