Asign a Cost for a IFC library object
I'm looking to create a library for IFC objects, specifically for lighting fixtures in BlenderBIM. Is it possible to specify the cost of the light fixture when I initially create the library object? I'd like it so that when I add the lighting fixture from the library to a project, the cost calculation automatically updates. Has anyone done this, or can you guide me on how to achieve it?
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Hi @Stealthmasterflex,
In this video @SigmaDimensions shows us the way to plan and costs in BB.
In the project I'm developing, soon I will also need to address these issues.
From a cost update point of view, I think it's not very appropriate to assign the cost directly in the object library. Bear in mind that the cost may vary over time and according to the project's life cycle (feasibility study, construction, maintenance, retrofit, demolition, etc.) and this may lead to the need to update the object library.
One method is to assign a classification (IfcClassificationReference) and update the cost based on that reference.
More thoughts in the future.
from the OSArch chat: _It is not something we have implemented yet, but it can be done. We have "the possibility to generate a quantity-based cost schedule for occurrences based on types with rate-based cost schedules." https://ifc43-docs.standards.buildingsmart.org/IFC/RELEASE/IFC4x3/HTML/lexical/IfcCostItem.htm _
You can currently create a Schedule of rates, and have each lighting fixture type assigned to a cost item: The cost value of your cost item is effectively your cost rate. The missing implementation is the juicy one --> generating/updating a cost schedule based on the product types.
After some thought, the " Generate cost schedule from types" isn't as quick to implement as I thought.
A cost item will hold information such as 1 $ per linear meter, square meter, cubic meter. But this is not enough assign the correct quantity and to calculate the cost . We need to establish rules of measurements for each product type in the schema such that the correct Quantity from a quantity set can be used.
These vary around the world, but I'm happy to implement the UK rules of measurements as it has been on my whish list for the past 2 years.
@Moult ..on another note, we also need to implement a handler to create quantity sets when creating objects, and updating these quantities when the geometry is updated - currently this is manual and can create discrepancies between geometry and quantity/total cost
@SigmaDimensions this would be awesome :-)
After reviewing all the insightful responses here, it appears embedding the price directly into the IFC library object may not be the best approach. The challenge of consistently updating the library file could become problematic over time. Using the "Schedule of Rates" method seems more logical, or perhaps sticking with the current method of assigning a fixed price. Additionally, the capability for automatic updates of quantities would be a beneficial feature to consider.