What is ifcopenshell.api.run ... "edit_object_placement" useful for?

bernd

a minimalisic spatial structure is added to a ifcfile as follows ... from https://github.com/IfcOpenShell/IfcOpenShell/blob/v0.7.0/src/blenderbim/scripts/obj2ifc.py#L116-L127

        site = ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcSite", name="My Site")
        building = ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcBuilding", name="My Building")
        self.storey = ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcBuildingStorey", name="My Storey" )

        ifcopenshell.api.run("aggregate.assign_object", self.file, product=site, relating_object=project)
        ifcopenshell.api.run("aggregate.assign_object", self.file, product=building, relating_object=site)
        ifcopenshell.api.run("aggregate.assign_object", self.file, product=self.storey, relating_object=building)

        ifcopenshell.api.run("geometry.edit_object_placement", self.file, product=site)
        ifcopenshell.api.run("geometry.edit_object_placement", self.file, product=building)
        ifcopenshell.api.run("geometry.edit_object_placement", self.file, product=self.storey)

What does the lines ifcopenshell.api.run("geometry.edit_object_placement", self.file, product=site) exactly do?

Coen

What does the lines ifcopenshell.api.run("geometry.edit_object_placement", self.file, product=site) exactly do?

I think it allows for a transformation of an object?

In this code snippet it's used to make an array of beams

for i in range(0, length_total_x, center_to_center_distance):

            matrix_x = numpy.array(
                            (
                                (1.0, 0.0, 0.0, i),
                                (1.0, 1.0, 1.0, profile_offset_y),
                                (0.0, 0.0, 0.0, 0.0),
                                (0.0, 0.0, 0.0, 1.0),
                            )
                        )

            matrix_x = numpy.array(matrix_x)

            occurrence =  run("root.create_entity", model, ifc_class="IfcBeam", name=beam_name)
            representation = run("geometry.add_profile_representation", model, context=representations["body"], profile=profile, depth=beam_length_y) 

            run("geometry.edit_object_placement",model, product=occurrence, matrix=matrix_x) 
            run("spatial.assign_container", model, relating_structure=storey, product=occurrence)
            run("geometry.assign_representation", model, product=occurrence, representation=representation)
            run("style.assign_representation_styles", model, shape_representation=representation, styles=[style])

bernd

But why is it needed for Spatial structure objects without representation?

Moult

@bernd just because they do not have a representation doesn't mean that it shouldn't have a placement. For example, the placement of a building storey uses its Z ordinate to specify the elevation. Similarly, a placement at the building or site level makes it easy to shift the entire building / site relative to it.