Code:
Function Vektor_Angle(ByVal X1 As Double, ByVal Y1 As Double, ByVal Z1 As Double, _
ByVal X2 As Double, ByVal y2 As Double, ByVal z2 As Double) As Double
Dim oTemp(2) As Double
Dim Pi As Double
Pi = 4 * Atn(1)
oTemp(0) = X1 * X2 + Y1 * y2 + Z1 * z2
oTemp(1) = Sqr(X1 ^ 2 + Y1 ^ 2 + Z1 ^ 2)
oTemp(2) = Sqr(X2 ^ 2 + y2 ^ 2 + z2 ^ 2)
oTemp(1) = oTemp(1) * oTemp(2)
oTemp(0) = oTemp(0) / oTemp(1)
oTemp(0) = ArcCos(oTemp(0), Pi)
Vektor_Angle = (360 / (2 * Pi)) * oTemp(0)
End Function
Function ArcCos(ByVal X As Double, ByVal Pi As Double) As Double
If X = 1 Then
ArcCos = 0
ElseIf X = -1 Then
ArcCos = Pi
ElseIf X < 1 And X > -1 Then
ArcCos = Atn(-X / Sqr((-X * X) + 1)) + Pi / 2
End If
End Function