#2319 Add documentation for IfcDiff

src/ifcdiff/ifcdiff.py

@@ -34,6 +34,38 @@ from deepdiff import DeepDiff
 
 
 class IfcDiff:
+    """Main IfcDiff application
+
+    If you are using IfcDiff as a library, this is the class you should use.
+
+    :param old_file: Filepath to the old file
+    :type old_file: string
+    :param new_file: Filepath to the new file
+    :type new_file: string
+    :param output_file: Filepath to the output JSON file to store the diff
+        results
+    :type output_file: string
+    :param relationships: List of relationships to check. An empty list means
+        that only geometry and attributes are compared.
+    :type relationships: list[string]
+    :param is_shallow: True if you want only the first difference to be listed.
+        False if you want all differences to be checked. Choosing False means
+        that comparisons will take longer.
+    :type is_shallow: bool
+    :param filter_elements: An IFC filter query if you only want to compare a
+        subset of elements. For example: ``.IfcWall`` to only compare walls.
+    :type filter_elements: string
+
+    Example::
+
+        from ifcdiff import IfcDiff
+
+        ifc_diff = IfcDiff("/path/to/old.ifc", "/path/to/new.ifc", "/path/to/diff.json")
+        ifc_diff.diff()
+        print(ifc_diff.change_register)
+        ifc_diff.export()
+    """
+
     def __init__(self, old_file, new_file, output_file, relationships=None, is_shallow=True, filter_elements=None):
         self.old_file = old_file
         self.new_file = new_file
@@ -101,7 +133,6 @@ class IfcDiff:
                 },
                 diff_file,
                 indent=4,
-                cls=DiffEncoder,
             )
 
     def load(self):
@@ -173,9 +204,9 @@ class IfcDiff:
     def diff_element_geometry(self, old, new):
         old_placement = ifcopenshell.util.placement.get_local_placement(old.ObjectPlacement)
         new_placement = ifcopenshell.util.placement.get_local_placement(new.ObjectPlacement)
-        if not np.allclose(old_placement[:,3], new_placement[:,3], atol=self.precision):
+        if not np.allclose(old_placement[:, 3], new_placement[:, 3], atol=self.precision):
             return True
-        if not np.allclose(old_placement[0:3,0:3], new_placement[0:3,0:3], atol=1e-2):
+        if not np.allclose(old_placement[0:3, 0:3], new_placement[0:3, 0:3], atol=1e-2):
             return True
         old_openings = [o.RelatedOpeningElement.GlobalId for o in getattr(old, "HasOpenings", []) or []]
         new_openings = [o.RelatedOpeningElement.GlobalId for o in getattr(new, "HasOpenings", []) or []]
@@ -218,7 +249,7 @@ class IfcDiff:
                 new_item.get_info_2(recursive=True),
                 custom_operators=[DiffTerminator()] if self.is_shallow else [],
                 math_epsilon=self.precision,
-                exclude_regex_paths=[r".*id']$"]
+                exclude_regex_paths=[r".*id']$"],
             )
         except:
             return True
@@ -249,14 +280,6 @@ class DiffTerminator:
             raise Exception("Terminated")
 
 
-class DiffEncoder(json.JSONEncoder):
-    def default(self, obj):
-        try:
-            return json.JSONEncoder.default(self, obj)
-        except:
-            return str(obj)
-
-
 if __name__ == "__main__":
     parser = argparse.ArgumentParser(description="Show the difference between two IFC files")
     parser.add_argument("old", type=str, help="The old IFC file")

src/ifcopenshell-python/docs/conf.py

@@ -60,7 +60,7 @@ extensions = ["autoapi.extension"]
 autoapi_type = 'python'
 
 # autoapi works by reading source code instead of importing modules
-autoapi_dirs = ['../ifcopenshell']
+autoapi_dirs = ['../ifcopenshell', '../../ifcdiff']
 
 # autoapi_options doesn't have show-module-summary, as it tends to create one
 # page per function which contradicts the presentation of showing all functions

src/ifcopenshell-python/docs/ifcdiff.rst

@@ -1,16 +1,124 @@
 IfcDiff
 =======
 
-This documentation is free software! You are free to contribute and help write
+IfcDiff is both a CLI utility and library that lets you compare the changes
-this document.
+between two IFC models. Changes are made on the assumption that the GlobalId of
+an element in one model is consistent with the same element in another model.
+You may compare geometric changes, and changes in various IFC relationships and
+properties. IfcDiff supports comparing across different IFC schema versions.
 
-.. toctree::
+Changes will be sorted into three lists:
-   :maxdepth: 1
-   :caption: Contents:
 
-Indices and tables
+- **Added**: a list of GlobalIds of elements present in the new file but not
-------------------
+  present in the old file.
+- **Deleted**: a list of GlobalIds of elements present in the old file but not
+  present in the new file.
+- **Changed**: A list of GlobalIds of elements present in both the old and new
+  file, but changes were detected. A list of changes are provided.
 
-* :ref:`genindex`
+There are different methods of installation, depending on your situation.
-* :ref:`modindex`
+
-* :ref:`search`
+1. **Source installation** is recommended for users wanting to use the latest
+   code as a library or a CLI utility.
+2. **Using the BlenderBIM Add-on** is recommended for non-developers wanting a
+   graphical interface.
+
+Source installation
+-------------------
+
+1. :doc:`Install IfcOpenShell <ifcopenshell-python/installation>`
+2. `Clone the source code <https://github.com/IfcOpenShell/IfcOpenShell/tree/v0.7.0/src/ifcdiff>`_.
+3. ``pip install -r requirements.txt``
+
+Here is a minimal example of how to use IfcDiff as a Python module or CLI
+utility:
+
+::
+
+    $ python -m ifcdiff -h
+    usage: ifcdiff.py [-h] [-o OUTPUT] [-r RELATIONSHIPS] old new
+
+    Show the difference between two IFC files
+
+    positional arguments:
+      old                   The old IFC file
+      new                   The new IFC file
+
+    options:
+      -h, --help            show this help message and exit
+      -o OUTPUT, --output OUTPUT
+                            The JSON diff file to output. Defaults to diff.json
+      -r RELATIONSHIPS, --relationships RELATIONSHIPS
+                            A list of space-separated relationships, chosen from "type", "property", "container", "aggregate", "classification"
+    $ python -m ifcdiff old.ifc new.ifc
+    $ cat diff.json
+
+Here is a minimal example of how to use IfcDiff as a library:
+
+.. code-block:: python
+
+    from ifcdiff import IfcDiff
+
+    ifc_diff = IfcDiff("/path/to/old.ifc", "/path/to/new.ifc", "/path/to/diff.json")
+    ifc_diff.diff()
+    print(ifc_diff.change_register)
+    ifc_diff.export()
+
+.. seealso::
+
+   For more information on how to use IfcDiff as a library, check out the :doc:`API
+   reference <autoapi/ifcdiff/index>`.
+
+
+Using the BlenderBIM Add-on
+---------------------------
+
+The BlenderBIM Add-on is a Blender based graphical interface to IfcOpenShell.
+Other than providing a graphical IFC authoring platform, it also comes with
+IfcOpenShell, its utilities, and a Python shell built-in. This means you don't
+need to install Python first, and you also can compare your IfcOpenShell
+scripting to what you see with a visual model viewer, or use a graphical
+interface to access the IfcOpenShell utilities.
+
+1. Install the BlenderBIM Add-on by following the `BlenderBIM Add-on
+   installation documentation
+   <https://blenderbim.org/docs/users/installation.html>`_.
+
+2. Launch Blender. Change to the **Scene Properties** tab in the **Properties
+   Panel**. Scroll down to the **IFC Quality Control > IFC Diff** panel.
+
+3. Browse to your old IFC file, new IFC file.
+
+4. Optionally add any relationships you want to check.
+
+5. Optionally type in a filter query.
+
+6. Press **Execute IFC Diff**
+
+TODO: add pictures and make this clearer for non-developers.
+
+Geometry changes
+----------------
+
+IfcDiff compares geometry changes using the underlying IFC geometric definition.
+This means that if a shape is described in one file as an extrusion, and as a
+mesh in another file, it is considered to be a change in geometry, even if they
+resolve to be the same boundary representation.
+
+Geometric tolerance is defined using the precision defined in the new IFC model.
+
+Relationships
+-------------
+
+By default, IfcDiff only compares changes in attributes and geometry. You may
+wish to optionally specify more relationships to compare. You may choose from:
+
+- **type**: detects changes in the type relationship, such as when an
+  occurrence now belongs to a different type.
+- **property**: detects changes in property sets, properties, quantity sets,
+  and quantities. Also includes detected changes in inherited properties.
+- **container**: detects changes in the spatial container, handling indirect
+  containment such as when an element is part of an aggregate.
+- **aggregate**: detects changes in aggregation.
+- **classification**: detects changes in classification references. Also
+  includes detected changes in inherited classifications.

src/ifcopenshell-python/docs/ifcopenshell-python/installation.rst

@@ -91,9 +91,10 @@ Using the BlenderBIM Add-on
 
 The BlenderBIM Add-on is a Blender based graphical interface to IfcOpenShell.
 Other than providing a graphical IFC authoring platform, it also comes with
-IfcOpenShell and a Python shell built-in. This means you don't need to install
+IfcOpenShell, its utilities, and a Python shell built-in. This means you don't
-Python first, and you also can compare your IfcOpenShell scripting to what you
+need to install Python first, and you also can compare your IfcOpenShell
-see with a visual model viewer.
+scripting to what you see with a visual model viewer, or use a graphical
+interface to access the IfcOpenShell utilities.
 
 1. Install the BlenderBIM Add-on by following the `BlenderBIM Add-on
    installation documentation