Schedule of Rates - edit cost value using python

steverugi · December 2023

I had posted this discussion at the end of a different thread relating to Bill of Quantities, I post it again here hoping to receive a hint on how to resolve it :D

problem:

adding a cost item to a cost schedule [PRICEDBILLOFQUANTITIES] is a straightforward process in python for both value and quantity, but if I need to add an item to a cost schedule[SCHEDULEOFRATES] it gets complicated to set the unit of measurement of the added value, since (I guess) it comes from the quantity, which is not present in a schedule of rates.

add a cost item to a cost schedule (Bill of Quantity)

# add cost item 
item1 = ifcopenshell.api.run("cost.add_cost_item", model, cost_schedule = schedule)
# edit cost item's attributes Name and Identification
ifcopenshell.api.run("cost.edit_cost_item", model, cost_item = item1, attributes = {"Name": "Concrete works", "Identification":'1.1'})
# add a value to the cost item
ratevalue = ifcopenshell.api.run("cost.add_cost_value", model, parent = item1)
# edit the cost item value setting the attribute "AppliedValue" to 5.0
ifcopenshell.api.run("cost.edit_cost_value", model, cost_value = ratevalue, attributes = {"AppliedValue": 5.0})

result:

to add its quantity

quantity = ifcopenshell.api.run("cost.add_cost_item_quantity", model, cost_item = item1, ifc_class="IfcQuantityArea")
ifcopenshell.api.run("cost.edit_cost_item_quantity", model, physical_quantity=quantity, attributes =  {"Name": "room area", "AreaValue": 23.5})

with the following output

Great!

add a cost item to a cost schedule (Schedule of Rates, not a Bill of Quantities)

# add cost item 
item1 = ifcopenshell.api.run("cost.add_cost_item", model, cost_schedule = schedule)
# edit cost item's attributes Name and Identification
ifcopenshell.api.run("cost.edit_cost_item", model, cost_item = item1, attributes = {"Name": "Concrete works", "Identification":'1.1'})
# add a value to the cost item
ratevalue = ifcopenshell.api.run("cost.add_cost_value", model, parent = item1)
# edit the cost item value setting the attribute "AppliedValue" to 5.0
ifcopenshell.api.run("cost.edit_cost_value", model, cost_value = ratevalue, attributes = {"AppliedValue": 5.0})

from the output

the unit of measurement is set to U

checking the attributes of IfcCostValue from buildingsmart.org I can see the one to edit (UnitBasis)

which accepts an IfcMeasureWithUnit type, made out of two attributes:

which made me stop there, without going any further

using the UI

the two values to edit of a cost item in a Schedule of Rates are UnitBasisValue and UnitBasisUnit

if I enter the values

I get the expected result:

question:

How do I edit (assign) the cost value's unit in python to show it in the cost schedule when it's a SCHEDULEOFRATES ?

I tried to understand the python code of edit_cost_value.py at: code

but I couldn't crack it

any help would be greatly appreciated
...and Merry Christmas !