57 lines
2.4 KiB
Python
57 lines
2.4 KiB
Python
# IfcOpenShell - IFC toolkit and geometry engine
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# Copyright (C) 2025 Thomas Krijnen <thomas@aecgeeks.com>
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#
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# This file is part of IfcOpenShell.
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#
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# IfcOpenShell is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Lesser General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# IfcOpenShell is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public License
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# along with IfcOpenShell. If not, see <http://www.gnu.org/licenses/>.
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import ifcopenshell.util.representation
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from ifcopenshell import entity_instance
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def get_basis_curve(alignment: entity_instance) -> entity_instance:
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"""
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Returns the basis curve for an alignment. This curve is the geometric representation that is used
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as the basis curve for vertical and cant alignments.
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:param alignment: The alignment
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:return: The geometric representation that is used as a basis curve, typically an IfcCompositeCurve, or None if the alignment does not have a representation
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Example:
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.. code:: python
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alignment = model.by_type("IfcAlignment")[0]
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composite_curve = ifcopenshell.api.alignment.get_basis_curve(alignment)
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"""
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axis = None
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representations = ifcopenshell.util.representation.get_representations_iter(alignment)
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for representation in representations:
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if (
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(representation.RepresentationIdentifier == "Axis" and representation.RepresentationType == "Curve2D")
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or (
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representation.RepresentationIdentifier == "FootPrint"
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and representation.RepresentationType == "Curve2D"
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)
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or (representation.RepresentationIdentifier == "Axis" and representation.RepresentationType == "Curve3D")
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): # in the case of IfcPolyline or IfcIndexedPolyCurve with 3D points
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axis = representation
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return None if axis.Items == None or len(axis.Items) == 0 else axis.Items[0]
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if axis == None and 0 < len(alignment.Decomposes):
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parent_alignment = alignment.Decomposes[0].RelatingObject
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return get_basis_curve(parent_alignment)
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return None
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