Minor fix to IfcCityJSON and migrate IfcCityJSON docs to sphinx

src/ifcopenshell-python/docs/ifccityjson.rst

@@ -3,3 +3,62 @@ IfcCityJSON
 
 IfcCityJSON is a converter for CityJSON files and IFC. It currently only
 supports one-way conversion from CityJSON to IFC.
+
+Source installation
+-------------------
+
+1. :doc:`Install IfcOpenShell <ifcopenshell-python/installation>`
+2. `Clone the source code <https://github.com/IfcOpenShell/IfcOpenShell/tree/v0.7.0/src/ifccityjson>`_.
+3. ``cd /path/to/IfcOpenShell/src/ifccityjson``
+4. ``pip install .``
+
+Usage
+-----
+
+An extended ifccityjson tutorial can be found on `the OSARCH wiki
+<https://wiki.osarch.org/index.php?title=Ifccityjson>`_. Here's the built-in
+documentation:
+
+.. code-block:: console
+
+    $ python -m ifccityjson -h
+
+    usage: __main__.py [-h] -i INPUT [-o OUTPUT] [-n NAME] [--split-lod] [--no-split-lod] [--lod LOD]
+
+    options:
+      -h, --help            show this help message and exit
+      -i INPUT, --input INPUT
+                            input CityJSON file
+      -o OUTPUT, --output OUTPUT
+                            output IFC file. Standard is output.ifc
+      -n NAME, --name NAME  Attribute containing the name
+      --split-lod           Split the file in multiple LoDs
+      --no-split-lod        Do not split the file in multiple LoDs
+      --lod LOD             extract LOD value (example: 1.2)
+
+The example file that could be used is example/3D_BAG_example.json
+
+.. code-block:: console
+
+    python ifccityjson.py -i example/geometries.json -o output.ifc -n identificatie
+
+The following geometries are implemented:
+
+- [x] "MultiPoint"
+- [x] "MultiLineString"
+- [x] "MultiSurface"
+- [x] "CompositeSurface"
+- [x] "Solid": exterior shell
+- [ ] "Solid": interior shell
+- [x] "MultiSolid"
+- [x] "CompositeSolid"
+- [ ] "GeometryInstance" 
+
+TODO:
+
+- [x] CityJSON Attributes as IFC properties in 'CityJSON_attributes' pset
+- [x] Implement georeferencing
+- [x] Do not use template IFC for new IFC file, but make IFC file from scratch
+- [x] Create mapping to IFC for all CityJSON object types & semantic surfaces
+- [ ] Implement conversion of all CitYJSON geometries
+- [x] Implement conversion of all LODs instead of only the most detailed