code: function(n){
          var mult = Math.sqrt(n*n/this.dot(this));
          return new Vec3(this.x*mult, this.y*mult, this.z*mult);
      }
docs: Creates a new vector from the current vector with the same direction but with provided length/magnitude.
  @memberof Vec3#
  @param   {Number} n
  @returns {Vec3}