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Andrej730
139 lines
4.9 KiB
ReStructuredText
139 lines
4.9 KiB
ReStructuredText
IfcDiff
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=======
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IfcDiff is both a CLI utility and library that lets you compare the changes
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between two IFC models. Changes are made on the assumption that the GlobalId of
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an element in one model is consistent with the same element in another model.
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You may compare geometric changes, and changes in various IFC relationships and
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properties. IfcDiff supports comparing across different IFC schema versions.
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Changes will be sorted into three lists:
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- **Added**: a list of GlobalIds of elements present in the new file but not
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present in the old file.
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- **Deleted**: a list of GlobalIds of elements present in the old file but not
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present in the new file.
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- **Changed**: A list of GlobalIds of elements present in both the old and new
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file, but changes were detected. A list of changes are provided.
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There are different methods of installation, depending on your situation.
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1. **PyPI** is recommended for developers using Pip.
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2. **Using the BlenderBIM Add-on** is recommended for non-developers wanting a
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graphical interface.
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3. **Source installation** is recommended for users wanting to use the latest
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code as a library or a CLI utility.
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PyPI
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----
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.. code-block::
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pip install ifcdiff
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Using the BlenderBIM Add-on
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---------------------------
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The BlenderBIM Add-on is a Blender based graphical interface to IfcOpenShell.
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Other than providing a graphical IFC authoring platform, it also comes with
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IfcOpenShell, its utilities, and a Python shell built-in. This means you don't
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need to install Python first, and you also can compare your IfcOpenShell
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scripting to what you see with a visual model viewer, or use a graphical
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interface to access the IfcOpenShell utilities.
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1. Install the BlenderBIM Add-on by following the `BlenderBIM Add-on
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installation documentation
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<https://docs.bonsaibim.org/users/installation.html>`_.
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2. Launch Blender. Change to the **Scene Properties** tab in the **Properties
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Panel**. Scroll down to the **IFC Quality Control > IFC Diff** panel.
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3. Browse to your old IFC file, new IFC file.
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4. Optionally add any relationships you want to check.
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5. Optionally type in a filter query.
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6. Press **Execute IFC Diff**
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TODO: add pictures and make this clearer for non-developers.
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Source installation
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-------------------
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1. :doc:`Install IfcOpenShell <ifcopenshell-python/installation>`
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2. `Clone the source code <https://github.com/IfcOpenShell/IfcOpenShell/tree/v0.8.0/src/ifcdiff>`_.
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3. ``cd /path/to/IfcOpenShell/src/ifcdiff``
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4. ``pip install -r requirements.txt``
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Here is a minimal example of how to use IfcDiff as a Python module or CLI
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utility:
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.. code-block:: console
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$ python -m ifcdiff -h
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usage: ifcdiff.py [-h] [-o OUTPUT] [-r RELATIONSHIPS] old new
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Show the difference between two IFC files
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positional arguments:
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old The old IFC file
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new The new IFC file
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options:
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-h, --help show this help message and exit
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-o OUTPUT, --output OUTPUT
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The JSON diff file to output. Defaults to diff.json
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-r RELATIONSHIPS, --relationships RELATIONSHIPS
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A list of space-separated relationships, chosen from "type", "property", "container", "aggregate", "classification"
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$ python -m ifcdiff old.ifc new.ifc
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$ cat diff.json
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Here is a minimal example of how to use IfcDiff as a library:
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.. code-block:: python
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from ifcdiff import IfcDiff
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ifc_diff = IfcDiff("/path/to/old.ifc", "/path/to/new.ifc", "/path/to/diff.json")
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ifc_diff.diff()
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print(ifc_diff.change_register)
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ifc_diff.export()
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.. seealso::
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For more information on how to use IfcDiff as a library, check out the :doc:`API
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reference <autoapi/ifcdiff/index>`.
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You can also alias it to a command:
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.. code-block:: bash
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alias ifcdiff='python -m ifcdiff'
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Geometry changes
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----------------
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IfcDiff compares geometry changes using the underlying IFC geometric definition.
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This means that if a shape is described in one file as an extrusion, and as a
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mesh in another file, it is considered to be a change in geometry, even if they
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resolve to be the same boundary representation.
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Geometric tolerance is defined using the precision defined in the new IFC model.
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Relationships
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-------------
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By default, IfcDiff only compares changes in attributes and geometry. You may
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wish to optionally specify more relationships to compare. You may choose from:
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- **type**: detects changes in the type relationship, such as when an
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occurrence now belongs to a different type.
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- **property**: detects changes in property sets, properties, quantity sets,
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and quantities. Also includes detected changes in inherited properties.
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- **container**: detects changes in the spatial container, handling indirect
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containment such as when an element is part of an aggregate.
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- **aggregate**: detects changes in aggregation.
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- **classification**: detects changes in classification references. Also
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includes detected changes in inherited classifications.
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