getPointAt( u, optionalTarget ) {

		const t = this.getUtoTmapping( u );
		return this.getPoint( t, optionalTarget );

	}
This method returns a vector in 2D or 3D space (depending on the curve definition)
for the given interpolation factor. Unlike {@link Curve#getPoint}, this method honors the length
of the curve which equidistant samples.

@param {number} u - A interpolation factor representing a position on the curve. Must be in the range `[0,1]`.
@param {(Vector2|Vector3)} [optionalTarget] - The optional target vector the result is written to.
@return {(Vector2|Vector3)} The position on the curve. It can be a 2D or 3D vector depending on the curve definition.