Time to transition from 2D takeoff to 3D BIM

Building Information Modelling, or BIM, is being increasingly used across the construction industry to make project delivery more efficient and more predictable. However, amongst quantity surveyors and estimators, BIM adoption is still quite low - Kreo’s recent survey revealed that over 80% of them currently get their measurements from 2D drawings.

However, many are now beginning to consider transitioning to BIM and switching to 3D takeoff. In this blog, we will discuss the benefits and drawbacks of such a transition compared to sticking to 2D takeoff, ideally making it easier for you to decide whether it is time for you to consider 3D BIM takeoff tools.

We were genuinely curious as to why quantity surveyors were so hesitant to work with BIM, and decided to dig deeper into the reasons by conducting a series of interviews with our clients. We found that, despite all the noise surrounding BIM adoption, many of the architects, clients and other stakeholders quantity surveyors collaborate with only work with drawings and do not use BIM in their process. This, alongside other factors, can help explain why quantity surveyors prefer to rely on 2D drawings for quantity takeoff.

These factors include: 

• Familiarity
  • Taking off quantities from 2D drawings is familiar and reliable, with clear  measurement rules and tools
  • Quantity surveyors already have extensive experience with obtaining 2D takeoff. By contrast, if they switch to BIM they would need to learn how to best utilise these new 3D takeoff tools, which requires investment of time and money, as well as organisational change

• Lack of detailed information
  • 2D drawings will frequently have more detail and project information than BIM models, which are often incomplete and do not contain enough information to carry out quantity takeoff properly
  • BIM authoring software tools were not designed with quantity surveyors and estimators in mind. Many BIM models lack information, design detail and buildable geometric representation to be a reliable source of measurements

• Transition Costs
  • The cost of licensing software tools for 2D takeoff is much lower than the licenses for 3D takeoff. 
    • In addition, quantity surveyors and estimators must also buy the various BIM authoring tools such as Autodesk Revit, Tekla, etc.
  • Training and hiring personnel
    • There is a lack of skilled BIM personnel who can support estimators and quantity surveyors in their effort to take off quantities from BIM models
      

• Lack of access to BIM models
  • It is still common for architects and project owners in the pre-construction phase to provide quantity surveyors with 2D drawings from BIM rather than BIM models themselves for reasons to do with:
    • Intellectual property rights over BIM designs
    • Fear of unauthorised changes to the model (version control) that may lead to contractual disputes
    • Construction contract law, which still relies on 2D drawings for bills of quantities 

Once you consider all these factors and obstacles, it would appear that there is not much incentive for quantity surveyors and estimators to make the switch from 2D takeoff to 3D BIM. However, despite all these challenges, there are many benefits to making the transition to BIM-based quantity takeoff and estimating, including: 

• Gaining a competitive advantage
  • Increasingly, BIM is becoming a tender requirement for public sector construction projects and for privately funded ones
    
    
• Speed
  • You can take off quantities from BIM in less than two hours, and thus save up to three weeks compared to working from drawings
  • Federated models (architecture, structure, MEP) allow you to identify buildability issues and take off quantities from the entire model, which saves massive amounts of time and effort
    

• Accuracy
  • BIM-based measurements can significantly reduce the human errors that arise when working with 2D drawings
  • 3D Takeoff tools can be particularly useful to you if your projects include foundation and structural frame, since these structural elements require strength and stability calculations that are performed numerically using 3D models
    • If you’re already using a 3D model to carry out these calculations, you can save yourself time by also using it in the whole process of carrying out takeoff
  • Many elements are geometrically complex; thus it can be very difficult or even impossible to use 2D measurements to determine their area and volume, whereas with 3D takeoff you get these values ​​automatically

• Flexibility
  • BIM allows you to automate reporting (bills of quantities, estimates, cost plans) by adding cost and classification codes to model properties 
  • You can produce industry standard cost breakdowns (NRM, SMM, Masterformat, etc.) 
  • You can easily update the reports for design variations made in BIM models
  • You can link quantities to cost databases to produce estimates

Before the advent of specialized software products for BIM takeoff, quantity surveyors and estimators had to figure out for themselves how to use BIM for their purposes. However, there is a growing number of specialized software tools for 3D BIM Takeoff – such as Kreo Takeoff – which makes the transition to BIM much smoother and faster

Kreo’s mission is to help quantity surveyors and estimators address the challenges they face with BIM implementation. To serve this goal, we offer features such as: 

• Safe and easy model sharing 
• Kreo Takeoff was developed to provide architects or BIM designers with a cloud platform through which they can share  BIM models with . quantity surveyors and estimators so that they can take off quantities from them, but cannot change or download original BIM files
• The fact that the platform is cloud-based encourages collaboration, facilitating clarifications about any incomplete information in the model or instant updates regarding any changes to it
  

• Best practices for BIM design for easy and accurate quantity takeoff 
• Because BIM use is still quite rare among quantity surveyors, BIM designers are not accustomed to taking QS’s needs into account. For this reason, we have developed an eBook with a set of best practices, with simple guidelines for architects and BIM designers to ensure that the BIM models they produce are optimized for quantity takeoff
  

• Information modeling as it should be
  • Identity and fill the information gaps in the BIM model by using advanced AI algorithms
  • Automate classification 
  • Automate measurements
  • Automate data mapping for bills of quantities and bills of materials
    
• Information modeling is the most important and misused aspect of BIM. Kreo Takeoff helps you 

• Accuracy
• Kreo, unlike all other BIM takeoff tools, relies on its own geometry engine to measure quantities rather than model properties. You can always check the measurements by using our 3D Ruler
  

• Bridging the gap between 3D BIM and 2D drawings
• As BIM is adopted more widely by QS’ and estimators and BIM modeling quality improves, 2D drawings’ role as the only reliable source of information for takeoff will diminish. In the meantime, you can get most quantities quicker and more easily from BIM, while using our  2D takeoff tool*  to fill the information gaps in BIM models

The construction industry is notorious for its resistance to change, but a growing number of architects, project owners (both private and public) and contractors are transitioning to BIM-based project delivery, encouraged by government BIM mandates for public infrastructure projects.

While It may be premature for certain quantity surveyors and estimators to make the switch to 3D takeoff right now, we believe that they should challenge their preconceived notions of BIM and give it a chance to show its true potential. 

If you’re interested in giving 3D takeoff from BIM a try, sign up for a free trial of Kreo Takeoff and see how much time and effort it could save you.