Module Contents#

class ifcopenshell.api.cost.unassign_cost_item_quantity.Usecase(file, cost_item=None, products=None)#

Removes quantities of a cost item that are calculated on products

A cost item may have quantities that are parametrically calculated on physical products. This lets you remove those quantities. This means that any future changes in the physical product’s dimensions will not have any impact on the cost item.



Return type



schedule = ifcopenshell.api.run("cost.add_cost_schedule", model)
item = ifcopenshell.api.run("cost.add_cost_item", model, cost_schedule=schedule)

# Let's imagine a unit cost of 5.0 per unit volume
value = ifcopenshell.api.run("cost.add_cost_value", model, parent=item)
ifcopenshell.api.run("cost.edit_cost_value", model, cost_value=value,
    attributes={"AppliedValue": 5.0})

slab = ifcopenshell.api.run("root.create_entity", model, ifc_class="IfcSlab")
# Usually the quantity would be automatically calculated via a
# graphical authoring application but let's assign a manual quantity
# for now.
qto = ifcopenshell.api.run("pset.add_qto", model, product=slab, name="Qto_SlabBaseQuantities")
ifcopenshell.api.run("pset.edit_qto", model, qto=qto, properties={"NetVolume": 42.0})

# Now let's parametrically link the slab's quantity to the cost
# item. If the slab is edited in the future and 42.0 changes, then
# the updated value will also automatically be applied to the cost
# item.
ifcopenshell.api.run("cost.assign_cost_item_quantity", model,
    cost_item=item, products=[slab], prop_name="NetVolume")

# Let's change our mind and remove the parametric connection
ifcopenshell.api.run("cost.unassign_cost_item_quantity", model,
    cost_item=item, products=[slab])