/// <summary>
/// Returns the rotationaxis of a orthogonal matrix and the rotation angle.
/// </summary>
/// <param name="Angle">Angle of the rotation of the matrix</param>
/// <returns></returns>
public LineType GetRotationAxis(ref double Angle)
{
Matrix M = this;
xyz P1 = new xyz(1, 0, 0);
xyz P2 = M * P1;
xyz P3 = M * P2;
LineType Result;
if (P2.Equals(P1))
{
P1 = new xyz(0, 1, 0);
P2 = M * P1;
P3 = M * P2;
if (P2.Equals(P1))
{
Result = new LineType(P1, new xyz(1, -1, 0));
Angle = Utils.Angle(new xyz(0, 0, 1), M * (new xyz(0, 0, 1)), new xyz(1, 1, 0));
if (System.Math.Abs(Angle) < 0.000001)
{
Result = new LineType(xyz.Null, new xyz(0, 0, 1));
}
return(Result);
}
}
Plane Plane1 = new Plane(((P1 + P2) * 0.5), P2 - P1);
Plane Plane2 = new Plane(((P2 + P3) * 0.5), P3 - P2);
return(Plane1.Cross(Plane2));
}
