Adds IfcPolyline representation for alignment. Also some general cleanup

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

@@ -50,7 +50,8 @@ Future versions of this API may support:
 from .add_stationing_referent import add_stationing_referent
 from .add_vertical_layout import add_vertical_layout
 from .create_layout_segment import create_layout_segment
-from .create_alignment import create
+from .create import create
+from .create_as_polyline import create_as_polyline
 from .create_by_pi_method import create_by_pi_method
 from .create_from_csv import create_from_csv
 from .create_segment_representations import create_segment_representations
@@ -81,6 +82,7 @@ __all__ = [
     "add_vertical_layout",
     "create_layout_segment",
     "create",
+    "create_as_polyline",
     "create_by_pi_method",
     "create_from_csv",
     "create_segment_representations",

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

@@ -171,7 +171,7 @@ def _add_segment_to_layout(file: ifcopenshell.file, layout: entity_instance, seg
     prev_segment = layout.IsNestedBy[0].RelatedObjects[-3] if 2 < len(layout.IsNestedBy[0].RelatedObjects) else None
     name = f"{_get_segment_start_point_label(prev_segment,segment)} ({ifcopenshell.util.stationing.station_as_string(file,station)})"
     referent = ifcopenshell.api.alignment.add_stationing_referent(
-        file, segment, basis_curve=basis_curve, distance_along=dist_along, station=station, name=name
+        file, segment, distance_along=dist_along, station=station, name=name
     )
 
     if len(curve.Segments) == 2 and layout.is_a("IfcAlignmentHorizontal"):

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

@@ -142,4 +142,4 @@ def _add_zero_length_segment(file: ifcopenshell.file, layout: entity_instance) -
         ]
 
     name = f"{_get_segment_start_point_label(segment,None)} {ifcopenshell.util.stationing.station_as_string(file,0.0)}"
-    ifcopenshell.api.alignment.add_stationing_referent(file, segment, curve, 0.0, 0.0, name=name)
+    ifcopenshell.api.alignment.add_stationing_referent(file, segment, 0.0, 0.0, name=name)

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

@@ -0,0 +1,57 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2025 Thomas Krijnen <thomas@aecgeeks.com>
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# IfcOpenShell is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+
+import ifcopenshell
+import ifcopenshell.api.alignment
+import ifcopenshell.api.geometry
+from ifcopenshell import entity_instance
+
+import math
+from collections.abc import Sequence
+
+
+def _create_polyline_representation(file: ifcopenshell.file, alignment: entity_instance, points: Sequence[Sequence[float]]) -> None:
+    """
+    Create geometric representation for the alignment based on an IfcPolyline
+
+    :param alignment: The alignment for which the representation is being created
+    :return: None
+    """
+    expected_type = "IfcAlignment"
+    if not alignment.is_a(expected_type):
+        raise TypeError(f"Expected {expected_type} but got {alignment.is_a()}")
+
+    axis_geom_subcontext = ifcopenshell.api.alignment.get_axis_subcontext(file)
+
+    placement = file.createIfcLocalPlacement(
+        PlacementRelTo=None,
+        RelativePlacement=file.createIfcAxis2Placement3D(Location=file.createIfcCartesianPoint(Coordinates=(0.0, 0.0, 0.0))),
+    )
+        
+    curve = file.createIfcPolyLine(Points=points)
+
+    representation = file.createIfcShapeRepresentation(
+        ContextOfItems=axis_geom_subcontext,
+        RepresentationIdentifier="Axis",
+        RepresentationType="Curve3D",
+        Items=(curve,),
+    )
+
+
+    alignment.ObjectPlacement = placement
+    ifcopenshell.api.geometry.assign_representation(file, alignment, representation)

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(),

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

@@ -76,10 +76,9 @@ def create(
         _add_zero_length_segment(file, layout)
 
     # define stationing
-    basis_curve = ifcopenshell.api.alignment.get_basis_curve(alignment)
     name = ifcopenshell.util.stationing.station_as_string(file, start_station)
     referent = ifcopenshell.api.alignment.add_stationing_referent(
-        file, alignment, basis_curve, 0.0, start_station, name
+        file, alignment, 0.0, start_station, name
     )
     ifcopenshell.api.nest.reorder_nesting(file, referent, -1, 0)
 
@@ -88,4 +87,4 @@ def create(
     if project:
         ifcopenshell.api.aggregate.assign_object(file, products=[alignment], relating_object=project)
 
-    return alignment
+    return alignment

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

@@ -0,0 +1,68 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2025 Thomas Krijnen <thomas@aecgeeks.com>
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# IfcOpenShell is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+
+import ifcopenshell
+import ifcopenshell.api.aggregate
+import ifcopenshell.api.alignment
+import ifcopenshell.api.nest
+import ifcopenshell.util.stationing
+
+from ifcopenshell import entity_instance
+
+from ifcopenshell.api.alignment._create_polyline_representation import _create_polyline_representation
+from ifcopenshell.api.alignment._add_zero_length_segment import _add_zero_length_segment
+from collections.abc import Sequence
+
+
+def create_as_polyline(
+    file: ifcopenshell.file,
+    name: str,
+    points: Sequence[entity_instance],
+    start_station: float = 0.0,
+) -> entity_instance:
+    """
+    Creates a new IfcAlignment with an IfcPolyline representation.
+
+    The IfcAlignment is aggreated to IfcProject
+
+    :param file:
+    :param name: name assigned to IfcAlignment.Name
+    :param points: sequence of points defining the polyline
+    :param start_station: station value at the start of the alignment
+    :return: Returns an IfcAlignment
+    """
+    alignment = file.createIfcAlignment(
+        GlobalId=ifcopenshell.guid.new(),
+        Name=name,
+    )
+
+    _create_polyline_representation(file, alignment, points)
+
+    # define stationing
+    name = ifcopenshell.util.stationing.station_as_string(file, start_station)
+    referent = ifcopenshell.api.alignment.add_stationing_referent(
+        file, alignment, 0.0, start_station, name
+    )
+    ifcopenshell.api.nest.reorder_nesting(file, referent, -1, 0)
+
+    # IFC 4.1.4.1.1 Alignment Aggregation To Project
+    project = file.by_type("IfcProject")[0]
+    if project:
+        ifcopenshell.api.aggregate.assign_object(file, products=[alignment], relating_object=project)
+
+    return alignment

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

@@ -26,6 +26,7 @@ import ifcopenshell.util.representation
 def get_curve(alignment: entity_instance) -> entity_instance:
     """
     Returns the geometric representation curve for an alignment.
+    An alignment without layouts will have a curve of type IfcPolyLine or IfcIndexedPolyCurve
     A horizontal only will have a curve of type IfcCompositeCurve
     A horizontal+vertical will have a curve of type IfcGradientCurve
     A horizontal+vertical+cant will have a curve of tyep IfcSegmentedReferenceCurve

src/ifcopenshell-python/test/api/alignment/test_create.py

@@ -22,7 +22,7 @@ import ifcopenshell.api.context
 import ifcopenshell.api.unit
 
 
-def test_create_alignment():
+def test_create():
     file = ifcopenshell.file(schema="IFC4X3_ADD2")
     project = file.createIfcProject(GlobalId=ifcopenshell.guid.new(), Name="Test")
     length = ifcopenshell.api.unit.add_si_unit(file, unit_type="LENGTHUNIT")
@@ -69,3 +69,4 @@ def test_create_alignment():
                 assert ifcopenshell.api.alignment.has_zero_length_segment(
                     a
                 )  # there is a check in this function for the geometry curve
+

src/ifcopenshell-python/test/api/alignment/test_create_as_polyline.py

@@ -0,0 +1,50 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2025 Thomas Krijnen <thomas@aecgeeks.com>
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# IfcOpenShell is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+
+import pytest
+import ifcopenshell.api.alignment
+import ifcopenshell.api.unit
+
+
+def test_create_as_polyline():
+    file = ifcopenshell.file(schema="IFC4X3_ADD2")
+    project = file.createIfcProject(GlobalId=ifcopenshell.guid.new(), Name="Test")
+    length = ifcopenshell.api.unit.add_si_unit(file, unit_type="LENGTHUNIT")
+    ifcopenshell.api.unit.assign_unit(file, units=[length])
+
+    points = [
+    file.createIfcCartesianPoint((945.2, 583.6,  50.0)),
+    file.createIfcCartesianPoint((756.3, 871.7,  66.2)),
+    file.createIfcCartesianPoint(( 567.4, 1159.7,   78.5)),
+    file.createIfcCartesianPoint(( 379.4, 1448.3,    86.8)),
+    file.createIfcCartesianPoint(( 201.7, 1743.3,   91.1)),
+    file.createIfcCartesianPoint((  36.8,  2045.7,   91.3)),
+    file.createIfcCartesianPoint((-118.9, 2353.0,   87.5)),
+    file.createIfcCartesianPoint((-274.3, 2660.4,   79.7)),
+    file.createIfcCartesianPoint((-429.6, 2967.8,   68.3)),
+    file.createIfcCartesianPoint((-585.0, 3275.2,   56.2 )),
+            ]
+
+
+    alignment = ifcopenshell.api.alignment.create_as_polyline(file,"A1",points)
+    curve = ifcopenshell.api.alignment.get_curve(alignment)
+    assert curve.is_a("IfcPolyline")
+    assert len(curve.Points) == 10
+
+
+test_create_as_polyline()

src/ifcopenshell-python/test/api/alignment/test_create_by_pi_method.py

@@ -22,7 +22,7 @@ import ifcopenshell.api.context
 import ifcopenshell.api.unit
 
 
-def test_create_alignment_pi_method():
+def test_create_by_pi_method():
     file = ifcopenshell.file(schema="IFC4X3")
     project = file.createIfcProject(GlobalId=ifcopenshell.guid.new(), Name="Test")
     length = ifcopenshell.api.unit.add_conversion_based_unit(file, name="foot")
@@ -64,4 +64,4 @@ def test_create_alignment_pi_method():
     )  # segments in vertical layout
 
 
-test_create_alignment_pi_method()
+test_create_by_pi_method()