diff --git a/LoopStructural/interpolators/supports/_2d_structured_grid.py b/LoopStructural/interpolators/supports/_2d_structured_grid.py
index 72f641c7..ffc9f6be 100644
--- a/LoopStructural/interpolators/supports/_2d_structured_grid.py
+++ b/LoopStructural/interpolators/supports/_2d_structured_grid.py
@@ -3,7 +3,6 @@
 
 """
 
-from ast import Not
 import logging
 
 from typing import Tuple
diff --git a/LoopStructural/modelling/__init__.py b/LoopStructural/modelling/__init__.py
index 2521ab0f..e720e8dd 100644
--- a/LoopStructural/modelling/__init__.py
+++ b/LoopStructural/modelling/__init__.py
@@ -6,12 +6,12 @@
 __all__ = [
     "GeologicalModel",
     "ProcessInputData",
-    "Loop3DView",
     "Map2LoopProcessor",
     "LoopProjectfileProcessor",
 ]
 from ..utils import getLogger
 from ..utils import LoopImportError
+from .core.geological_model import GeologicalModel
 
 logger = getLogger(__name__)
 from ..modelling.input import (
diff --git a/LoopStructural/modelling/features/_geological_feature.py b/LoopStructural/modelling/features/_geological_feature.py
index 557134d3..a96179e1 100644
--- a/LoopStructural/modelling/features/_geological_feature.py
+++ b/LoopStructural/modelling/features/_geological_feature.py
@@ -6,7 +6,7 @@
 from ...modelling.features import BaseFeature
 from ...utils import getLogger
 from ...modelling.features import FeatureType
-from ...interpolators import GeologicalInterpolator, DiscreteInterpolator
+from ...interpolators import GeologicalInterpolator
 import numpy as np
 from typing import Optional, List, Union
 from ...datatypes import ValuePoints, VectorPoints
diff --git a/LoopStructural/modelling/features/fold/_fold_rotation_angle.py b/LoopStructural/modelling/features/fold/_fold_rotation_angle.py
index 518165fc..2b548f9b 100644
--- a/LoopStructural/modelling/features/fold/_fold_rotation_angle.py
+++ b/LoopStructural/modelling/features/fold/_fold_rotation_angle.py
@@ -2,7 +2,8 @@
 from scipy.optimize import curve_fit
 
 from ....modelling.features.fold._fold_rotation_angle_feature import (
-    fourier_series,
+    # fourier_series,
+    trigo_fold_profile,
 )
 from ....modelling.features.fold import SVariogram
 
@@ -53,9 +54,10 @@ def fit_fourier_series(
             wl = self.svario.find_wavelengths(lags=lags, nlag=nlag, lag=lag)
             # for now only consider single fold wavelength
             wl = wl[0]
-        guess = np.zeros(4)
-        guess[3] = wl  # np.max(limb_wl)
-        logger.info(f"Guess: {guess[0]} {guess[1]} {guess[2]} {guess[3]}")
+        guess = np.zeros(3)
+        guess[1] = wl
+        guess[2] = np.deg2rad(45)  # np.max(limb_wl)
+        logger.info(f"Guess: {guess[0]} {guess[1]} {guess[2]} ")
         # mask nans
         mask = np.logical_or(~np.isnan(self.fold_frame_coordinate), ~np.isnan(self.rotation_angle))
         logger.info(
@@ -71,7 +73,7 @@ def fit_fourier_series(
             try:
                 # try fitting using wavelength guess
                 popt, pcov = curve_fit(
-                    fourier_series,
+                    trigo_fold_profile,
                     self.fold_frame_coordinate[mask],
                     np.tan(np.deg2rad(self.rotation_angle[mask])),
                     guess,
@@ -81,7 +83,7 @@ def fit_fourier_series(
                     # if fitting failed, try with just 0s
                     logger.info("Running curve fit without initial guess")
                     popt, pcov = curve_fit(
-                        fourier_series,
+                        trigo_fold_profile,
                         self.fold_frame_coordinate[mask],
                         np.tan(np.deg2rad(self.rotation_angle[mask])),
                     )
@@ -90,15 +92,14 @@ def fit_fourier_series(
                     popt = guess
                     logger.error("Could not fit curve to S-Plot, check the wavelength")
             self.fitted_params = popt
-            logger.info(f"Fitted: {popt[0]} {popt[1]} {popt[2]} {popt[3]}")
+            logger.info(f"Fitted: {popt[0]} {popt[1]} {popt[2]} ")
             self.fold_rotation_function = lambda x: np.rad2deg(
                 np.arctan(
-                    fourier_series(
+                    trigo_fold_profile(
                         x,
                         self.fitted_params[0],
                         self.fitted_params[1],
                         self.fitted_params[2],
-                        self.fitted_params[3],
                     )
                 )
             )
diff --git a/LoopStructural/modelling/features/fold/_fold_rotation_angle_feature.py b/LoopStructural/modelling/features/fold/_fold_rotation_angle_feature.py
index cab62603..5abe6ca8 100644
--- a/LoopStructural/modelling/features/fold/_fold_rotation_angle_feature.py
+++ b/LoopStructural/modelling/features/fold/_fold_rotation_angle_feature.py
@@ -1,6 +1,5 @@
 import numpy as np
 from ....modelling.features import BaseFeature
-
 from ....utils import getLogger
 
 logger = getLogger(__name__)
@@ -46,6 +45,40 @@ def evaluate_value(self, location):
         return r
 
 
+# class BaseFoldProfile(ABCMeta):
+#     def __init__(self):
+#         pass
+
+#     @abstractmethod
+#     def params(self):
+#         pass
+
+
+#     @abstractmethod
+#     def __call__(self, s):
+#         pass
+
+
+# class TrigoFoldProfile(BaseFoldProfile):
+#     def __init__(self, origin, wavelength, inflectionpointangle):
+#         self.origin = origin
+#         self.wavelength = wavelength
+#         self.inflectionpointangle = inflectionpointangle
+#         self.tan_alpha_delta_half = np.tan(self.inflectionpointangle)
+
+#         self.tan_alpha_shift = 0
+
+#     def position_in_period(self, s):
+#         return (s - self.origin) / self.wavelength
+
+#     def __call__(self, s):
+#         x = self.position_in_period(s)
+#         return np.rad2deg(
+#             np.arctan(self.tan_alpha_delta_half * np.sin(2 * np.pi * x) + self.tan_alpha_shift)
+#         )
+# class FourierSeriesFoldProfile(BaseFoldProfile):
+
+
 def fourier_series(x, c0, c1, c2, w):
     """
 
@@ -65,3 +98,23 @@ def fourier_series(x, c0, c1, c2, w):
     # v.fill(c0)
     v = c0 + c1 * np.cos(2 * np.pi / w * x) + c2 * np.sin(2 * np.pi / w * x)
     return np.rad2deg(np.arctan(v))
+
+
+def trigo_fold_profile(s, origin, wavelength, inflectionpointangle):
+    """
+
+    Parameters
+    ----------
+    s
+    origin
+    wavelength
+    inflectionpointangle
+
+    Returns
+    -------
+
+    """
+    tan_alpha_delta_half = np.tan(inflectionpointangle)
+    tan_alpha_shift = 0
+    x = (s - origin) / wavelength
+    return np.rad2deg(np.arctan(tan_alpha_delta_half * np.sin(2 * np.pi * x) + tan_alpha_shift))