112 lines
4.6 KiB
Python
112 lines
4.6 KiB
Python
# IfcOpenShell - IFC toolkit and geometry engine
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# Copyright (C) 2022 Dion Moult <dion@thinkmoult.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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from typing import Any, Union
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import ifcopenshell.util.unit
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COORD = Union[tuple[float, float], tuple[float, float, float]]
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def add_axis_representation(
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file: ifcopenshell.file, context: ifcopenshell.entity_instance, axis: tuple[COORD, COORD]
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) -> ifcopenshell.entity_instance:
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"""Adds a new axis representation
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Certain objects are typically "axis-based", such as walls, beams,
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and columns. This means you can represent them abstractly by simply
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drawing a single line either in 2D (such as for walls) or 3D (for beams
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and columns). Humans can understand this axis-based representation as
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being a simplification of a layered extrusion or a profile that is being
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extruded along that axis and joined to other elements.
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Using an axis-based representation makes it easy for users and computers
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to analyse connectivity and spatial relationships, as well as makes it
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easy to parametrically edit these objects by simply stretching the start
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or end of the axis.
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For now, only simple straight line axes are supported, represented by a
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start and end coordinate. The order is important. For walls, the start
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must be at the minimum local X ordinate, and the end at the maximum
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local X ordinate. For beams and columns, the start is at the minimum
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local Z ordinate, and the end of the maximum local Z ordinate. The first
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coordinate is the "start" and the second coordinate is the "end". This
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stat and end is then used to determine any parametric junctions with
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other elements.
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Using an axis-representation is optional, but highly recommended for
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"standard" representations of walls, beams, columns, and other
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structural members. A rule of thumb is that if you can draw it as a line
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on paper, you can probably represent it using an axis.
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:param context: The IfcGeometricRepresentationContext that the
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representation is part of. This must be either a
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Model/Axis/GRAPH_VIEW (3D) or Plan/Axis/GRAPH_VIEW (2D).
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:param axis: The axis, as a list of two coordinates, the coordinates
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being either a list of 2 or 3 float coordinates depending on whether
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the axis is 2D or 3D.
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:return: The newly created IfcShapeRepresentation entity
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Example:
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.. code:: python
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context = ifcopenshell.util.representation.get_context(model, "Plan", "Axis", "GRAPH_VIEW")
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axis = ifcopenshell.api.geometry.add_axis_representation(model,
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context=context, axis=[(0.0, 0.0), (1.0, 0.0)])
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"""
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usecase = Usecase()
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usecase.file = file
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usecase.settings = {
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"context": context,
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"axis": axis or [],
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}
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return usecase.execute()
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class Usecase:
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file: ifcopenshell.file
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settings: dict[str, Any]
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def execute(self):
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self.settings["unit_scale"] = ifcopenshell.util.unit.calculate_unit_scale(self.file)
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is_2d = len(self.settings["axis"][0]) == 2
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points = [self.convert_si_to_unit(p) for p in self.settings["axis"]]
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if self.file.schema == "IFC2X3":
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curve = self.file.createIfcPolyline([self.file.createIfcCartesianPoint(p) for p in points])
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else:
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if is_2d:
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curve = self.file.createIfcIndexedPolyCurve(
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self.file.createIfcCartesianPointList2D(points), None, False
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)
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else:
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curve = self.file.createIfcIndexedPolyCurve(
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self.file.createIfcCartesianPointList3D(points), None, False
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)
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return self.file.createIfcShapeRepresentation(
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self.settings["context"],
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self.settings["context"].ContextIdentifier,
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"Curve2D" if is_2d else "Curve3D",
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[curve],
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)
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def convert_si_to_unit(self, co):
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if isinstance(co, (tuple, list)):
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return [self.convert_si_to_unit(o) for o in co]
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return co / self.settings["unit_scale"]
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