diff --git a/Richtungsreduktion.py b/Richtungsreduktion.py
index 6b7f031..688f5eb 100644
--- a/Richtungsreduktion.py
+++ b/Richtungsreduktion.py
@@ -4,7 +4,7 @@ import ausgaben as aus
 import winkelumrechnungen as wu
 
 
-re = ellipsoide.Ellipsoid.init_name("Bessel")
+re = ellipsoide.EllipsoidBiaxial.init_name("Bessel")
 eta = lambda phi: sqrt(re.e_ ** 2 * cos(phi) ** 2)
 
 A = wu.gms2rad([327,0,0])
diff --git a/ellipsoide.py b/ellipsoide.py
index 2de6f6b..531f223 100644
--- a/ellipsoide.py
+++ b/ellipsoide.py
@@ -3,7 +3,7 @@ import winkelumrechnungen as wu
 import ausgaben as aus
 
 
-class Ellipsoid:
+class EllipsoidBiaxial:
     def __init__(self, a: float, b: float):
         self.a = a
         self.b = b
@@ -81,3 +81,47 @@ class Ellipsoid:
         for i in range(len(phii)):
             print(f"P3[{i}]: {aus.gms('phi', phii[i], 5)}\th = {round(hi[i], 5)} m")
         return phi, lamb, h
+
+class EllipsoidTriaxial:
+    def __init__(self, ax: float, ay: float, b: float):
+        self.ax = ax
+        self.ay = ay
+        self.b = b
+        self.ex = np.sqrt(self.ax**2 - self.b**2)
+        self.ey = np.sqrt(self.ay**2 - self.b**2)
+        self.ee = np.sqrt(self.ax**2 - self.ay**2)
+
+    @classmethod
+    def init_name(cls, name: str):
+        if name == "BursaFialova1993":
+            ax = 6378171.36
+            ay = 6378101.61
+            b = 6356751.84
+            return cls(ax, ay, b)
+        elif name == "BursaSima1980":
+            ax = 6378172
+            ay = 6378102.7
+            b = 6356752.6
+            return cls(ax, ay, b)
+        elif name == "Eitschberger1978":
+            ax = 6378173.435
+            ay = 6378103.9
+            b = 6356754.4
+            return cls(ax, ay, b)
+        elif name == "Bursa1972":
+            ax = 6378173
+            ay = 6378104
+            b = 6356754
+            return cls(ax, ay, b)
+        elif name == "Bursa1970":
+            ax = 6378173
+            ay = 6378105
+            b = 6356754
+            return cls(ax, ay, b)
+
+    def ell2cart(self, beta, lamb, u):
+        s1 = u**2 - self.b**2
+        s2 = -self.ay**2 * np.sin(beta)**2 - self.b**2 * np.cos(beta)**2
+        s3 = -self.ax**2 * np.sin(lamb)**2 - self.ay**2 * np.cos(lamb)**2
+
+        x = np.sqrt(u**2 + self.ex**2) * np.sqrt(np.cos(beta)**2 + self.ee**2/self.ex**2 * np.sin(beta)**2)
\ No newline at end of file
diff --git a/hausarbeit.py b/hausarbeit.py
index 95089b2..c9d79fd 100644
--- a/hausarbeit.py
+++ b/hausarbeit.py
@@ -2,7 +2,7 @@ from numpy import cos, sin, tan
 import winkelumrechnungen as wu
 import s_ellipse as s_ell
 import ausgaben as aus
-from ellipsoide import Ellipsoid
+from ellipsoide import EllipsoidBiaxial
 import Numerische_Integration.num_int_runge_kutta as rk
 import GHA.gauss as gauss
 import GHA.bessel as bessel
@@ -16,7 +16,7 @@ m2 = matrikelnummer[-2]
 m1 = matrikelnummer[-1]
 print(f"m1={m1}\tm2={m2}\tm3={m3}\tm4={m4}")
 
-re = Ellipsoid.init_name("Bessel")
+re = EllipsoidBiaxial.init_name("Bessel")
 nks = 3
 
 print(f"\na = {re.a} m\nb = {re.b} m\nc = {re.c} m\ne' = {re.e_}")
@@ -49,7 +49,7 @@ s12 = float("1"+m4+m3+m2+"."+m1+"0")
 #     print(f"{s} m, {aus.gms('phi', phi, nks)}, {aus.gms('lambda', lam, nks)}, {aus.gms('A', A, nks)}")
 
 # print("via Gauß´schen Mittelbreitenformeln")
-phi_p2, lambda_p2, A_p2 = gauss.gha1(Ellipsoid.init_name("Bessel"),
+phi_p2, lambda_p2, A_p2 = gauss.gha1(EllipsoidBiaxial.init_name("Bessel"),
                                      phi_p1=phi1,
                                      lambda_p1=lambda1,
                                      A_p1=A12,
diff --git a/koord_umrechnung_triaxial.py b/koord_umrechnung_triaxial.py
new file mode 100644
index 0000000..e1b894e
--- /dev/null
+++ b/koord_umrechnung_triaxial.py
@@ -0,0 +1,3 @@
+import numpy as np
+
+def ell2cart()
\ No newline at end of file