getPoint( t, optionalTarget = new Vector3() ) {

		const point = optionalTarget;

		const points = this.points;
		const l = points.length;

		const p = ( l - ( this.closed ? 0 : 1 ) ) * t;
		let intPoint = Math.floor( p );
		let weight = p - intPoint;

		if ( this.closed ) {

			intPoint += intPoint > 0 ? 0 : ( Math.floor( Math.abs( intPoint ) / l ) + 1 ) * l;

		} else if ( weight === 0 && intPoint === l - 1 ) {

			intPoint = l - 2;
			weight = 1;

		}

		let p0, p3; // 4 points (p1 & p2 defined below)

		if ( this.closed || intPoint > 0 ) {

			p0 = points[ ( intPoint - 1 ) % l ];

		} else {

			// extrapolate first point
			tmp.subVectors( points[ 0 ], points[ 1 ] ).add( points[ 0 ] );
			p0 = tmp;

		}

		const p1 = points[ intPoint % l ];
		const p2 = points[ ( intPoint + 1 ) % l ];

		if ( this.closed || intPoint + 2 < l ) {

			p3 = points[ ( intPoint + 2 ) % l ];

		} else {

			// extrapolate last point
			tmp.subVectors( points[ l - 1 ], points[ l - 2 ] ).add( points[ l - 1 ] );
			p3 = tmp;

		}

		if ( this.curveType === 'centripetal' || this.curveType === 'chordal' ) {

			// init Centripetal / Chordal Catmull-Rom
			const pow = this.curveType === 'chordal' ? 0.5 : 0.25;
			let dt0 = Math.pow( p0.distanceToSquared( p1 ), pow );
			let dt1 = Math.pow( p1.distanceToSquared( p2 ), pow );
			let dt2 = Math.pow( p2.distanceToSquared( p3 ), pow );

			// safety check for repeated points
			if ( dt1 < 1e-4 ) dt1 = 1.0;
			if ( dt0 < 1e-4 ) dt0 = dt1;
			if ( dt2 < 1e-4 ) dt2 = dt1;

			px.initNonuniformCatmullRom( p0.x, p1.x, p2.x, p3.x, dt0, dt1, dt2 );
			py.initNonuniformCatmullRom( p0.y, p1.y, p2.y, p3.y, dt0, dt1, dt2 );
			pz.initNonuniformCatmullRom( p0.z, p1.z, p2.z, p3.z, dt0, dt1, dt2 );

		} else if ( this.curveType === 'catmullrom' ) {

			px.initCatmullRom( p0.x, p1.x, p2.x, p3.x, this.tension );
			py.initCatmullRom( p0.y, p1.y, p2.y, p3.y, this.tension );
			pz.initCatmullRom( p0.z, p1.z, p2.z, p3.z, this.tension );

		}

		point.set(
			px.calc( weight ),
			py.calc( weight ),
			pz.calc( weight )
		);

		return point;

	}
Returns a point on the curve.

@param {number} t - A interpolation factor representing a position on the curve. Must be in the range `[0,1]`.
@param {Vector3} [optionalTarget] - The optional target vector the result is written to.
@return {Vector3} The position on the curve.