IFC based Quantity takeoff

[Ahmed_K]

Hi, 

I already developed a workflow to calculate quantities and building cost using archicad and excel, 

ArchiCAD to model, schedule, extract data : I used Classifications, properties, schedules

Excel to collect data, calculate, and manage data in multiple formats, 

Now, i want to improve, i looked into some posts  here in the forum, informations aren't enough to build a robust solution based on IFC, 

My idea is the following, 

IFC psets will used as filters and data containers, for units, quantity / item description, calculated quantity, price per unit etc, 

using IFC i can have access to data that can't be handled with properties and or classifications.

this data will be extracted using schedules, the rest of work in excel, 

I want to know how to start exploring IFC and what type of limitations can i face in this workflow ?

If someone is interested, this thread would be a GREAT PLACE to exchange and develop the workflow.

Thanks.

[Nathan Hildebrandt]

Your timing of this post is perfect Lukas Oelmüller is doing a presentation next Friday as part of ARCHINTENSIVE - Session 17 on openBIM and cost estimation. He has developed processes using IFC for cost estimation. I suggest watching that session. https://www.skewed.com.au/events/archintensive-2023

[SenecaDesignLLC]

I generate one massive schedule and save as and excel file, then my excel template collates and performs any remaining calculations that weren't logical in archicads properties or my gdl code.

I can in seconds list changes in lumber siding sheathing etc.

It's not ifc but it works very well

[ifcreport]

Great thread — the property set approach you're describing is a solid pattern for keeping QTO data model-native and avoiding double-entry.

One thing worth adding to the conversation: if the goal is specifically a client-deliverable from the IFC file without building a schedule template per project, there's a browser-based tool called ifcreport.app that I've been working on.

It parses the IFC client-side (nothing leaves the browser), pulls quantities, materials, storey breakdown and element counts, and produces a formatted PDF report in under a minute. Works with any IFC — Archicad, Revit, Tekla, Allplan. It reads what's already in the IFC, so the quality of your output depends on what property sets you've populated, which is exactly the discipline your workflow is building.

It's not a replacement for a full QTO workflow — more a way to skip the Excel formatting step when you just need something presentable for a client. Free tier covers 3 reports/month; Pro is €19/month.

Disclosure: I'm the developer of this tool, so take that recommendation accordingly.

[bimdo]

Hi @Ahmed_K 

Are you looking for a technical solution or more interested in the process?

• from a technical perspective Blender in combination with Bonsai is a pretty cool solution, ifcopenshell even more if you're interested to go more in coding.
• ifclite is a free webviewer which maybe can help you

My learnings with ifc and calculations:

• If you model elements as composites, you should know, that the sublayers have no base quantities. There are some software which can interpret that.
• If you model similar elements with different tools in archicad, you'll face unstructered quantities in the ifc too. Maybe this way of thinking is helping you too, I group elements in this categories like in Archicad in Ifc too, coz they are familiar to schedule.
• 
• if you want to recalculate outside of Archicad then Kabandy is a pretty cool tool, if you want to code yourself then ifcopenshell is the way. if you need something between and want to create nice dashboards without thinking about a hundreds of tools, then speckle is maybe an interesting solution for you.
• attention: checkout the buildingsmart page to understand how ifc is understanding some quantities, standard vs. archicad/ revit etc. interpretations. Anyway there are many quantities you'll find in archicad, but which will not be exported as a standard. But of course you can add them in the ifc scheme and then you would have the same quantities as you had it in Archicad and can then visualize the ifc or add additional information to the model with ifclite for example.

Is that supporting you?

[Ahmed_K]

Hi @bimdo  , 

Thanks so much for the detailed and highly informative response! You hit the nail on the head regarding the complexities of standard versus software-specific IFC interpretations, especially when dealing with composite elements in Archicad.

To answer your question :

I am indeed leaning heavily into the technical and coding side of things. I’ve actually been digging deep into IfcOpenShell to build my own custom quantity parser for a web application I am currently developing called CostWaves. Rather than relying on out-of-the-box interpretations, I wanted a solution that aligns exactly with my own specific national calculation standards 

To bypass the issues with unstructured quantities, my workflow involves precisely mapping the exact IFC quantities I need through customized Property Sets . This gives me complete control over the data structure, ensuring that the information my parser extracts is clean, predictable, and tailored to my pipeline. This entire IFC parsing module will be introduced into CostWaves very soon!

Your insights on tools like Speckle and Kabandy are also great to keep in mind for future dashboarding, but having that core control via IfcOpenShell is definitely the right foundation for what I'm building.

Thanks again for sharing your learnings,it perfectly validates the direction I'm taking!