Module Contents#

class ifcopenshell.api.cost.add_cost_item_quantity.Usecase(file, cost_item=None, ifc_class='IfcQuantityCount')#

Adds a new quantity associated with a cost item

Cost items calculate their subtotal by multiplying the sum of the cost item’s “values” by the sum of the cost item’s “quantities”. The quantities may be either parametrically linked to quantities measured on physical product, or manually specified.

The quantity must be of a particular type, common examples are:

  • IfcQuantityCount: to count the total occurrences of a product, useful for things like doors, windows, and furniture

  • IfcQuantityNumber: any other generic numeric quantity

  • IfcQuantityLength

  • IfcQuantityArea

  • IfcQuantityVolume

  • IfcQuantityWeight

  • IfcQuantityTime

A cost item must not mix quantities of different types.

If an IfcQuantityCount is used, then this API will automatically count all products that this cost item controls (see ifcopenshell.api.controls.assign_control) and prefill that quantity.

For all other quantity types, the quantity is left as zero and the user must either manually specify the quantity or parametrically link it using another API call.


The newly created quantity entity, chosen from the ifc_class parameter

Return type



chair = ifcopenshell.api.run("root.create_entity", model, ifc_class="IfcFurniture")
schedule = ifcopenshell.api.run("cost.add_cost_schedule", model)
item = ifcopenshell.api.run("cost.add_cost_item", model, cost_schedule=schedule)
ifcopenshell.api.run("control.assign_control", model,
    relating_control=cost_item, related_object=chair)

# Let's assume we want to count the amount of chairs to calculate our cost item
# Because this is an IfcQuantityCount the count will be automatically set to "1" chair
ifcopenshell.api.run("cost.add_cost_item_quantity", model,
    cost_item=item, ifc_class="IfcQuantityCount")