/// <summary>
/// Gets the space normal vector.
/// </summary>
/// <param name="point"></param>
/// <param name="curve"></param>
/// <returns></returns>
public static XYZ GetSpaceNormal(this Curve curve, XYZ point)
{
var line = curve as Line;
var p1 = line.GetEndPoint(0);
var p2 = line.GetEndPoint(1);
return(point.GetSpaceNormal(p1, p2));
}