public Vector3 GetNormal(float time, Vector3 up)
{
BezierPoint3D startPoint;
BezierPoint3D endPoint;
float timeRelativeToSegment;
this.GetCubicSegment(time, out startPoint, out endPoint, out timeRelativeToSegment);
return BezierCurve3D.GetNormalOnCubicCurve(timeRelativeToSegment, up, startPoint, endPoint);
}