Mentioned in #4593
The error message was (it was trying to access curves from the original mesh instead of dummy curve object):
```
Error: Python: Traceback (most recent call last):
File "\blenderbim\bim\module\geometry\operator.py", line 46, in execute
IfcStore.execute_ifc_operator(self, context)
File "\blenderbim\bim\ifc.py", line 349, in execute_ifc_operator
result = getattr(operator, "_execute")(context)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "\blenderbim\bim\module\geometry\operator.py", line 169, in _execute
core.add_representation(
File "\blenderbim\core\geometry.py", line 52, in add_representation
representation = ifc.run(
^^^^^^^^
File "\blenderbim\tool\ifc.py", line 34, in run
return ifcopenshell.api.run(command, IfcStore.get_file(), **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "\blenderbim\libs\site\packages\ifcopenshell\api\__init__.py", line 172, in run
result = usecase_class(ifc_file, **settings).execute()
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "\blenderbim\libs\site\packages\ifcopenshell\api\geometry\add_representation.py", line 73, in execute
return self.create_plan_representation()
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "\blenderbim\libs\site\packages\ifcopenshell\api\geometry\add_representation.py", line 170, in create_plan_representation
return self.create_annotation2d_representation()
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "\blenderbim\libs\site\packages\ifcopenshell\api\geometry\add_representation.py", line 833, in create_annotation2d_representation
items = [self.file.createIfcGeometricCurveSet(self.create_curves(is_2d=True))]
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "\blenderbim\libs\site\packages\ifcopenshell\api\geometry\add_representation.py", line 492, in create_curves
curves = self.create_curves_from_curve_ifc2x3(is_2d=is_2d, curve_object_data=dummy.data)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "\blenderbim\libs\site\packages\ifcopenshell\api\geometry\add_representation.py", line 575, in create_curves_from_curve_ifc2x3
for spline in self.settings["geometry"].splines:
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'Mesh' object has no attribute 'splines'
```
Basically if current mesh curve is non consequtive we handle it in similar way to b03c4da7b - convert it to curves using Blender and then save them to ifc.
The advantage is that it creates less curves in ifc because mesh method wasn't able to detect separate curves correctly if vertex order was messed up (usually it is) and it would create separate curve for each curve segment.
I've also replaced figuring vertex duplicates with `bmesh.ops.remove_doubles` manually with `bmesh.ops.remove_doubles` and it's now much faster. In some cases because of the manual calculations it was taking too long - in #3233 Ryan mentiones that it freezes blender, it wasn't really freezing Blender but to finish calculations it would take 10 minutes.
Now blender curves segments saved in IfcIndexedPolyCurves instead of creating individual polygons.
Also changed ShapeBuilder.polyline - now it will try to store points in IfcLineIndex where it's possible (previously it was storing just 2).
* Bug when switching representations when active object not selected.
* Bug when switching to a non MODEL_VIEW body representation would load the MODEL_VIEW one instead all the time.
* Add support for plan body representations.
The idea is to only triangulate non co-planar faces when required.
Timings for evaluation with matrix based algo.
IfcRoof/Roof found 3927 of 116178 polygons: 0.366638 sec
IfcWall/Wall.012 found 0 of 6 polygons: 0.000046 sec
So should be acceptable for common use cases
But with single precision in blender we may still be over occ precision with a 1e-6 epsilon.
* Ensure polygons are always coplanar
fix#1481
May adopt a bmesh approach instead ?
* Ensure polygons are coplanar
The bmesh version is lot faster than modifier one
Andrej730
