public void ShiftToB(CopyOfPoint3D b, double shift)
{
X1 += (b.X1 - X1) * shift / Dist(b);
X2 += (b.X2 - X2) * shift / Dist(b);
X3 += (b.X3 - X3) * shift / Dist(b);
}
public CopyOfPoint3D(CopyOfPoint3D other)
{
X1 = other.X1;
X2 = other.X2;
X3 = other.X3;
}