coplanarity condition for t-stepjoint

src/compas_timber/connections/joint.py

@@ -337,6 +337,7 @@ def _beam_ref_side_incidence_with_vector(beam_b, vector, ignore_ends=True):
 
         return ref_side_angles
 
+    @staticmethod
     def _are_beams_coplanar(beam_a, beam_b, tolerance=1e-3):
         """
         Checks if two beams are coplanar based on the cross product of their centerline directions.
@@ -356,7 +357,6 @@ def _are_beams_coplanar(beam_a, beam_b, tolerance=1e-3):
             True if the beams are coplanar, False otherwise.
         """
         # Compute the cross product of the centerline directions of the two beams
-        print(beam_a, beam_b)
         cross_product = beam_a.centerline.direction.cross(beam_b.centerline.direction)
 
         # Check dot products of the cross product with the normals of both beams' frames

src/compas_timber/connections/t_step_joint.py

@@ -100,8 +100,11 @@ def cross_beam_ref_side_index(self):
 
     @property
     def main_beam_ref_side_index(self):
-        ref_side_dict = self._beam_ref_side_incidence(self.cross_beam, self.main_beam, ignore_ends=True)
-        ref_side_index = min(ref_side_dict, key=ref_side_dict.get)
+        cross_beam_ref_side = self.cross_beam.ref_sides[self.cross_beam_ref_side_index]
+        ref_side_dict = self._beam_ref_side_incidence_with_vector(
+            self.main_beam, cross_beam_ref_side.normal, ignore_ends=True
+        )
+        ref_side_index = max(ref_side_dict, key=ref_side_dict.get)
         return ref_side_index
 
     def add_features(self):
@@ -110,14 +113,21 @@ def add_features(self):
         This method is automatically called when joint is created by the call to `Joint.create()`.
 
         """
+        # TODO: In the future the step, heel and tenon mortise depths should be proportional to the cross beam section wheareas the proportions are defined by the national norms.
+        # TODO: As well the step shape should maybe be defined automatically by the shear reqirements of the joint.
+
         assert self.main_beam and self.cross_beam  # should never happen
+        assert self._are_beams_coplanar(
+            self.main_beam, self.cross_beam
+        ), "The beams are not coplanar, the joint cannot be created."
 
         if self.features:
             self.main_beam.remove_features(self.features)
             self.cross_beam.remove_features(self.features)
 
         main_beam_ref_side = self.main_beam.ref_sides[self.main_beam_ref_side_index]
         cross_beam_ref_side = self.cross_beam.ref_sides[self.cross_beam_ref_side_index]
+
         # generate step joint notch features
         cross_feature = StepJointNotch.from_plane_and_beam(
             main_beam_ref_side,