Adds IfcPolyline representation for alignment. Also some general cleanup

src/ifcopenshell-python/ifcopenshell/api/alignment/add_stationing_referent.py

@@ -31,7 +31,6 @@ import numpy as np
 def add_stationing_referent(
     file: ifcopenshell.file,
     element: entity_instance,
-    basis_curve: entity_instance,
     distance_along: float,
     station: float,
     name: str,
@@ -41,8 +40,7 @@ def add_stationing_referent(
     If element is an IfcAlignment, IfcReferent.PredefinedType is set to "STATION", otherwise "POSITION"
 
     :param element: the element to receive the referent, expected to be an IfcAlignment or IfcAlignmentSegment
-    :param basis_curve: the basis curve for positining
-    :param distance_along: distance along the basis curve
+    :param distance_along: distance along the alignment curve
     :param station: station value
     :param name: name to assign to IfcReferent.Name, typically a stringized version of the station value
     :return: referent
@@ -52,32 +50,19 @@ def add_stationing_referent(
     .. code:: python
 
         alignment = model.by_type("IfcAlignment")[0]
-        basis_curve = ifcopenshell.api.alignment.get_basis_curve(alignment)
-        ifcopenshell.api.alignment.add_stationing_referent(model,entity=alignment,basis_curve=basis_curve,distance_along=0.0,station=100.0)
+        ifcopenshell.api.alignment.add_stationing_referent(model,entity=alignment,distance_along=0.0,station=100.0)
     """
+    alignment = element
+
+    if element.is_a("IfcAlignmentSegment"):
+        layout = element.Nests[0].RelatingObject
+        alignment = ifcopenshell.api.alignment.get_alignment(layout)
+
+    basis_curve = ifcopenshell.api.alignment.get_basis_curve(alignment)
+
     object_placement = None
     representation = None
     if basis_curve:
-        unit_scale = ifcopenshell.util.unit.calculate_unit_scale(file)
-
-        settings = ifcopenshell.geom.settings()
-        fn = ifcopenshell_wrapper.map_shape(settings, basis_curve.wrapped_data)
-        evaluator = ifcopenshell_wrapper.function_item_evaluator(settings, fn)
-        p = evaluator.evaluate(distance_along * unit_scale)
-        p = np.array(p)
-
-        x = float(p[0, 3]) / unit_scale
-        y = float(p[1, 3]) / unit_scale
-        z = float(p[2, 3]) / unit_scale
-
-        rx = float(p[0, 0])
-        ry = float(p[1, 0])
-        rz = float(p[2, 0])
-
-        ax = float(p[0, 2])
-        ay = float(p[1, 2])
-        az = float(p[2, 2])
-
         object_placement = file.createIfcLinearPlacement(
             RelativePlacement=file.createIfcAxis2PlacementLinear(
                 Location=file.createIfcPointByDistanceExpression(
@@ -88,12 +73,40 @@ def add_stationing_referent(
                     BasisCurve=basis_curve,
                 )
             ),
-            CartesianPosition=file.createIfcAxis2Placement3D(
-                Location=file.createIfcCartesianPoint((x, y, z)),
-                Axis=file.createIfcDirection((ax, ay, az)),
-                RefDirection=file.createIfcDirection((rx, ry, rz)),
-            ),
         )
+
+        is_valid_curve = True
+        if basis_curve.is_a("IfcPolyline") and len(basis_curve.Points) < 2:
+            is_valid_curve = False
+        elif basis_curve.is_a("IfcIndexedPolyCurve") and len(basis_curve.Points.CoordList) < 2:
+            is_valid_curve = False
+
+        if is_valid_curve:
+            unit_scale = ifcopenshell.util.unit.calculate_unit_scale(file)
+
+            settings = ifcopenshell.geom.settings()
+            fn = ifcopenshell_wrapper.map_shape(settings, basis_curve.wrapped_data)
+            evaluator = ifcopenshell_wrapper.function_item_evaluator(settings, fn)
+            p = evaluator.evaluate(distance_along * unit_scale)
+            p = np.array(p)
+
+            x = float(p[0, 3]) / unit_scale
+            y = float(p[1, 3]) / unit_scale
+            z = float(p[2, 3]) / unit_scale
+
+            rx = float(p[0, 0])
+            ry = float(p[1, 0])
+            rz = float(p[2, 0])
+
+            ax = float(p[0, 2])
+            ay = float(p[1, 2])
+            az = float(p[2, 2])
+
+            object_placement.CartesianPosition=file.createIfcAxis2Placement3D(
+                    Location=file.createIfcCartesianPoint((x, y, z)),
+                    Axis=file.createIfcDirection((ax, ay, az)),
+                    RefDirection=file.createIfcDirection((rx, ry, rz)),
+                )
     # this commented out code is what you would do to add a geometric representation of the referent
     # the example is a circle. a better way would be to pass a representation into the function
     #    representation = file.create_entity(
@@ -118,12 +131,6 @@ def add_stationing_referent(
     ifcopenshell.api.pset.edit_pset(file, pset=pset_stationing, properties={"Station": station})
     ifcopenshell.api.nest.assign_object(file, related_objects=[referent], relating_object=element)
 
-    alignment = element
-
-    if element.is_a("IfcAlignmentSegment"):
-        layout = element.Nests[0].RelatingObject
-        alignment = ifcopenshell.api.alignment.get_alignment(layout)
-
     if len(alignment.Positions) == 0:
         rel_positions = file.createIfcRelPositions(
             GlobalId=ifcopenshell.guid.new(),