How to take off quantities from BIM (with the best results)

Taking off quantities from BIM is not as hard as it used to be. With a plethora of tools out there providing the service, it should be easy.

So why aren’t we all doing it? The answer usually includes one or more of the following reasons:

1. We don’t have a BIM model because clients or architects don't want to share it with us
2. We don’t trust the results because we cannot easily check the dimensions and quantities in 3D
3. We don't know how to takeoff quantities from BIM because we are not familiar with Revit and other BIM authoring tools
4. We have no access to Revit or other authoring tools because they are expensive, difficult to learn and, most important, are not suitable for quantity takeoff.

The construction industry is fast embracing BIM, with 12% more companies using BIM year-on-year. So we can’t afford to be left behind. Whether we use BIM models now for our cost estimation or not, it’s soon going to be inevitable because more and more projects require BIM proficiency as a condition of a tender. So let’s get prepared.

Trusting the results is a more complicated story. It’s true that many quantity takeoff (QTO) tools don’t measure the right dimensions. With tools that don't do the job well, quantity surveyors risk duplicating their efforts and still rely on 2D drawings.

In this post, we’ll explain:

• Why QTO from BIM is important
• How to take off quantities from BIM to get the best results
• Suggestions for moving forward

Why is anyone taking off quantities from BIM?

In construction, taking off quantities refers to the process of identifying elements of construction works that can be measured and priced. It’s the first step in estimating the cost of your proposed construction project. 

Almost all construction projects have now been digitalised with the inventions of PDF and CAD. Building Information Modelling (BIM) is the next step. It’s not just a design, or a representation of what you want to build. The key is in the word “Information”. Your BIM model includes information on everything surrounding the project: geospatial information, dimensions, materials, specifications, costs… and much more. Your BIM model can continually be enhanced by multiple stakeholders over the whole life cycle of the project.

Taking off quantities from BIM should be more accurate, easier and faster. That’s why anyone would take off quantities from BIM, as opposed to a 2D model. But many BIM programs are still not up to scratch and require a large amount of manual tweaking. 

BIM authoring software such as Revit and Archicad were developed for architects and engineers in mind. It's not surprising that many aspects of construction quantity takeoff are overlooked or ignored in these tools. In addition, architects and engineers are as pressed for time as quantity surveyors and estimators so they to leave out a lot information or cut corners to meet tight deadlines. We believe that artificial intelligence can help us save massive amounts of time without sacrificing the accuracy.

How to take off quantities from a BIM model 

It doesn’t matter what state your BIM model is in, as long as it was designed in Autodesk Revit. If not, you’ll need to convert it into an Industry Foundation Classes (IFC) file before you start taking off quantities from BIM.

What If your client or architect does not want to share the Revit model with you because they are worried about their IP or you making unauthorised changes to it? You can ask them to upload a model themselves to Kreo by using Kreo's Revit Plugin.

Once the model is uploaded to Kreo the original Revit file cannot be changed or copied so the model authors can rest assured. Our .bim file format is a 3D equivalent of a PDF file widely used in 2D takeoff.

Step 1: Uploading the BIM model

Either you can use Kreo’s Revit plug-in or you can directly upload your .bim file(s) into Kreo. Kreo Takeoff federates your model for you - no need to worry about having different takeoffs for architectural, structural or MEP files. Start getting used to working from one model to avoid mistakes and save yourself the effort of manually combining multiple takeoff sheets into a single report.

Step 2: Fix your model

Kreo checks your federated model and identifies where there are major errors. It will spot, for example, where there is a giant column or wall that needs to be split into buildable sections. It will make recommendations for you to ensure the model is correct. Not your job? Don’t worry, it’s easy. Kreo fixes some issues for you straight away. You can also tell Kreo to ignore the problems you know won’t be crucial to taking off quantities correctly.

Step 3: Identify information gaps in the BIM model

Kreo's AI system will help you fill the information gaps so that you can get the most accurate takeoff report.

Step 4: Take off quantities from BIM!

This is the fun bit. Kreo takes off all the quantities for you from the BIM model automatically. You can sit back and watch! 

Step 5: Check measurements using our new 3D Ruler

If you are worried about the reliability and accuracy of the measured quantities you can now review and check every measurement using Kreo's 3D Ruler

Step 6: Create custom takeoff reports

Once you are confident about the measurements you can create your custom reports within Kreo by grouping quantities by material, design discipline (architecture, structural and MEP) or element type as well as industry-standard cost breakdown structure (NRM, Uniformat).

Step 6: Export for your bills of quantities to MS Excel

Share your model and results with anyone, as Kreo is cloud-based. You can export your QTO into Excel spreadsheets for further analysis in other programs, or to create your bills of quantities faster.

You can keep uploading BIM models with design changes as you go along. Keep your records in one place with Kreo. Control permissions for your company or external project stakeholders with advanced permission settings.

2 Tips and reminders for taking off quantities from BIM

Be brave! You’ll get cynics who don’t like to try new technology. But how can anyone know what it does if they don’t try it out? 

Perfection is the enemy of good. Those who worry this won’t get 100% accurate results should take a long hard look at current practices. Experts who use 2D drawings may be accurate if they have enough time. But in the pre-tender window, it’s usually rushed and vague estimates are used where accuracy could have been strived for.

BIM tools were created and are maintained by humans. Let us know if you notice any mistakes and help us improve. Revit’s QTO tool was good enough until Kreo developed a better way of taking off quantities from BIM. And we can keep getting better.

Quantity takeoff will improve

Quantity takeoff in construction is still far too laborious. In our survey with Construction Manager Magazine, 63% of professionals said QTO would be the first pre-construction process they’d automate.

By using artificial intelligence to take off quantities from BIM, we’ll see faster, more accurate results. We’ll see quantity surveyors and cost estimators spending their time more wisely on value engineering decisions. 

See for yourself

If you’re ready to start taking off quantities from BIM, you can get a free Kreo account now.Time to take off!