Bonsai: make dxf2ifc.py example script skip unsupported DXF entities

The script called Polyline.get_mode() on every modelspace entity, but
that method only exists on POLYLINE entities, so any typical DXF
containing lines, circles or text crashed with AttributeError before
converting anything. Test for POLYLINE polyface meshes with
dxftype()/is_poly_face_mesh instead and skip other entities with a
message, only create the spatial containment relation when products
exist, and take the input/output paths from the command line (matching
obj2ifc.py) instead of a hardcoded input.dxf/test.ifc.

Fixes #2151

This change was written with the assistance of an AI coding tool.

src/bonsai/scripts/dxf2ifc.py

@@ -16,20 +16,26 @@
 # You should have received a copy of the GNU General Public License
 # along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
 
+import argparse
+
 import ezdxf
 import ifcopenshell
 import ifcopenshell.guid
 
 
 class Dxf2Ifc:
+    def __init__(self, dxf_path, outfile):
+        self.dxf_path = dxf_path
+        self.outfile = outfile
+
     def execute(self):
         self.create_ifc_file()
-        doc = ezdxf.readfile("input.dxf")
+        doc = ezdxf.readfile(self.dxf_path)
         model = doc.modelspace()
         products = []
         for entity in model:
             print(entity)
-            if entity.get_mode() == "AcDbPolyFaceMesh":
+            if entity.dxftype() == "POLYLINE" and entity.is_poly_face_mesh:
                 ifc_faces = []
                 for face in entity.faces():
                     ifc_faces.append(
@@ -67,15 +73,18 @@ class Dxf2Ifc:
                             "Name": entity.dxf.layer,
                             "ObjectPlacement": self.placement,
                             "Representation": representation,
-                        }
+                        },
                     )
                 )
             else:
-                print("Not yet implemented")
+                print(f"Skipping unsupported entity: {entity.dxftype()}")
+        if products:
             self.file.createIfcRelContainedInSpatialStructure(
                 ifcopenshell.guid.new(), None, None, None, products, self.site
             )
-        self.file.write("test.ifc")
+        else:
+            print("No AcDbPolyFaceMesh entities found, writing an empty IFC")
+        self.file.write(self.outfile)
 
     def create_ifc_file(self):
         self.file = ifcopenshell.file()
@@ -97,14 +106,20 @@ class Dxf2Ifc:
                 "Name": "DXF Conversion",
                 "RepresentationContexts": [self.context],
                 "UnitsInContext": units,
-            }
+            },
         )
         self.site = self.file.create_entity(
             "IfcSite",
-            **{"GlobalId": ifcopenshell.guid.new(), "Name": "DXF Conversion Site", "ObjectPlacement": self.placement}
+            **{"GlobalId": ifcopenshell.guid.new(), "Name": "DXF Conversion Site", "ObjectPlacement": self.placement},
         )
         self.file.createIfcRelAggregates(ifcopenshell.guid.new(), None, None, None, self.project, [self.site])
 
 
-dxf2ifc = Dxf2Ifc()
-dxf2ifc.execute()
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description="Converts DXF polyface meshes (AcDbPolyFaceMesh) to an IFC")
+    parser.add_argument("dxf", type=str, help="The input DXF file")
+    parser.add_argument("-o", "--output", type=str, help="The output IFC file", default="out.ifc")
+    args = parser.parse_args()
+
+    dxf2ifc = Dxf2Ifc(args.dxf, args.output)
+    dxf2ifc.execute()