Lap bugfix

CHANGELOG.md

@@ -55,6 +55,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 * Fixed `AttributeError` when deserializing a model with Lap joints.
+* Fixed a bug in `compas_timber.fabrication.Lap` where `ref_side_index` failed for `0` by checking for `None` instead.
+* Fixed a bug in `compas_timber.fabrication.Lap` to handle the case when the vectors used to calculate the `inclination` angle are perpendicular.
+* Adjusted `angle_vectors_projected` function so that it returns `None` if any of the projections results in a zero-vector.
+
 ### Removed
 
 

src/compas_timber/connections/l_lap.py

@@ -1,3 +1,5 @@
+from compas.tolerance import TOL
+
 from compas_timber.errors import BeamJoiningError
 from compas_timber.fabrication import JackRafterCut
 from compas_timber.fabrication import Lap
@@ -64,8 +66,9 @@ def add_extensions(self):
             raise BeamJoiningError(self.elements, self, debug_info=str(ae), debug_geometries=geometries)
         except Exception as ex:
             raise BeamJoiningError(self.elements, self, debug_info=str(ex))
-        self.main_beam.add_blank_extension(start_main, end_main, self.main_beam_guid)
-        self.cross_beam.add_blank_extension(start_cross, end_cross, self.cross_beam_guid)
+        tol = TOL.absolute
+        self.main_beam.add_blank_extension(start_main + tol, end_main + tol, self.main_beam_guid)
+        self.cross_beam.add_blank_extension(start_cross + tol, end_cross + tol, self.cross_beam_guid)
 
     def add_features(self):
         """Adds the required joint features to both beams.

src/compas_timber/fabrication/lap.py

@@ -409,7 +409,7 @@ def from_volume_and_beam(cls, volume, beam, machining_limits=None, ref_side_inde
             raise ValueError("Volume must have 6 faces.")
 
         # get ref_side of the
-        if not ref_side_index:
+        if ref_side_index is None:
             ref_side_index = cls._get_optimal_ref_side_index(beam, volume)
         ref_side = beam.ref_sides[ref_side_index]
 
@@ -442,6 +442,8 @@ def from_volume_and_beam(cls, volume, beam, machining_limits=None, ref_side_inde
 
         # calculate the inclination of the lap
         inclination = angle_vectors_projected(zzaxis, front_plane.normal, yyaxis)
+        if inclination is None:
+            inclination = angle_vectors_signed(zzaxis, ref_side.xaxis, ref_side.normal, deg=True)
         inclination = 180 + inclination if inclination < 0 else inclination
 
         # calculate the slope of the lap
@@ -739,25 +741,23 @@ def _planes_from_params_and_beam(self, beam):
         tol = Tolerance()
         tol.absolute=1e-3
 
-        if self.machining_limits["FaceLimitedStart"]:
-            start_frame = self._start_frame_from_params_and_beam(beam)
-        else:
-            start_frame = beam.ref_sides[4]
+        start_frame = self._start_frame_from_params_and_beam(beam)
+
+        top_frame = beam.ref_sides[self.ref_side_index] # top should always be unlimited
+        top_frame.translate(top_frame.normal * TOL.absolute)
 
         if self.machining_limits["FaceLimitedEnd"]:
             end_frame = start_frame.translated(-start_frame.normal * self.length)
             end_frame.yaxis = -end_frame.yaxis
         else:
             end_frame = beam.ref_sides[5]
 
-        top_frame = beam.ref_sides[self.ref_side_index] # top should always be unlimited
-
         if self.machining_limits["FaceLimitedBottom"]:
             bottom_frame = Frame(start_frame.point, start_frame.zaxis, start_frame.yaxis)
             angle = angle_vectors_signed(top_frame.xaxis, -start_frame.xaxis, top_frame.yaxis)
             bottom_frame = bottom_frame.translated(bottom_frame.zaxis * (self.depth/math.sin(angle)))
         else:
-            bottom_frame = beam.ref_sides[4]
+            bottom_frame = beam.opp_side(self.ref_side_index)
 
         if self.machining_limits["FaceLimitedFront"]:
             front_frame = bottom_frame.rotated(math.radians(self.lead_angle), bottom_frame.xaxis, point=bottom_frame.point)

src/compas_timber/utils/__init__.py

@@ -20,6 +20,7 @@
 from compas.geometry import intersection_line_plane
 from compas.geometry import closest_point_on_segment
 from compas.geometry import intersection_line_line
+from compas.tolerance import TOL
 
 
 def intersection_line_line_param(line1, line2, max_distance=1e-6, limit_to_segments=True, tol=1e-6):
@@ -307,14 +308,16 @@ def angle_vectors_projected(vector_a, vector_b, normal):
     Returns
     -------
     float
-        The angle between the two projected vectors
+        The angle between the two projected vectors. If any of the projections results in a zero vector, None is returned.
     """
     if isinstance(normal, (Plane, Frame)):
         normal = normal.normal
 
     projection = Projection.from_plane(Plane(Point(0, 0, 0), normal))
     proj_vect_a = vector_a.transformed(projection)
     proj_vect_b = vector_b.transformed(projection)
+    if TOL.is_zero(proj_vect_a.length) or TOL.is_zero(proj_vect_b.length):
+        return None
     return angle_vectors_signed(proj_vect_a, proj_vect_b, normal, deg=True)