/// <summary>
/// Constructs the rotation matrix for an angle counter-clockwise (right-handed) about an arbitrary axis
/// </summary>
/// <param name="angle">Angle in radians</param>
static public Matrix RotationMatrix(Vector axis, double angle)
{
axis = axis.UnitVector();
var matrix = new Matrix(3, 3);
double cos = Math.Cos(angle);
double sin = Math.Sin(angle);
double oneMinusCos = 1 - cos;
matrix[0, 0] = cos + UtilityFunctions.Square(axis.X) * oneMinusCos;
matrix[0, 1] = axis.X * axis.Y * oneMinusCos - axis.Z * sin;
matrix[0, 2] = axis.X * axis.Z * oneMinusCos + axis.Y * sin;
matrix[1, 0] = axis.Y * axis.X * oneMinusCos + axis.Z * sin;
matrix[1, 1] = cos + UtilityFunctions.Square(axis.Y) * oneMinusCos;
matrix[1, 2] = axis.Y * axis.Z * oneMinusCos - axis.X * sin;
matrix[2, 0] = axis.Z * axis.X * oneMinusCos - axis.Y * sin;
matrix[2, 1] = axis.Z * axis.Y * oneMinusCos + axis.X * sin;
matrix[2, 2] = cos + UtilityFunctions.Square(axis.Z) * oneMinusCos;
return(matrix);
}