Building Information Modelling (BIM) and Computer Aided Design (CAD) are used throughout the architectural industry to help architects and designers thoroughly plan their building designs and ensure every eventuality has been covered. In recent times however, we have noticed that there has been a shift from using CAD to BIM. In our whitepaper, BIM Vs CAD; The Evolution of Architectural Technology, we ran a survey which found that 53% of survey respondents had made the switch from using BIM to CAD. What we wanted to find out next was why.



Whilst Building Information Modelling and Computer Aided Design are similar in their functionality, they do have quite a different overall offering. CAD has been around for a lot longer than BIM, as BIM essentially developed from CAD, and is therefore a more well-known and accepted practice. The main difference is that BIM files contain much more information than CAD files on the functionality of each individual element within the design and can therefore be relied upon more heavily for testing and analysing the structure.


To know why 53% of our survey respondents made the switch from using CAD to BIM, we need to delve a bit deeper into the results. Firstly, when asked which offers the fastest delivery, 74% of respondents stated that BIM provided the fastest delivery. In context, this means that it provides faster delivery of an overall project as more can be done within the system, whereas many of our respondents stated that CAD is quicker for smaller designs.


“CAD will die out in the future for larger projects. CAD will remain useful for producing quick details and simple 2D information”.


“CAD is better for smaller/quicker/simpler projects and in existing buildings whereas BIM is better for the larger or more complicated new ones. So, until BIM is streamlined it won’t be used for small projects or projects involving existing buildings not already on a BIM Model format”.


This indicates that many architects may have switched from CAD to BIM as it speeds up the process when working on a larger project. Those still using CAD are potentially creating smaller designs and therefore do not require the capabilities offered by BIM.


Another reason why architects have made the switch from using CAD to BIM is that there is a general feeling of BIM providing a better visualisation of the project; not only in the images you see but with the underlying information you receive. 74% of survey respondents stated that BIM provided the best visualisation when compared to CAD.


Another important issue to highlight is the cost savings involved in switching from CAD to BIM. This may not apply to everyone using these platforms though, as it depends entirely on the size and nature of the project. On survey respondent stated:

“By switching to BIM and a database-driven design approach, the cost savings and efficiencies are huge. For small practices working on very basic projects then CAD is probably still a cheaper alternative, however as soon as you start introducing complexity and multiple users BIM is a much better solution”.

 However, it is not just cost, speed or visualisation alone that encourages architects to make the switch. We asked survey respondents which factor was the most important to them when choosing BIM or CAD software; Low Cost, High Speed, Simplicity of Platform, Detail of the Visualisation, Detail of Additional Information Added or Other. 32% or respondents stated that ‘Simplicity of Platform’ was most important, which adds another factor to the decision. Anther respondent even told us that there was industry pressure to use BIM as some firms insist on it. Several respondents also agreed that it is a combination of these things which influences their decision:

 “Best value, which is a combination of more than one of the above elements”.

 Another respondent stated that a “Mixture of speed, cost and ability to use on various sizes of projects” was important to them. They continued to say that for “Small projects CAD works better, (for) large projects BIM is best”.

 It seems that there is a general feel in the industry that BIM will become the dominant practice in the years to come, but CAD still has its uses and can even be used in conjunction with BIM. Find out more about this in the BIM Vs CAD – The Evolution of Architectural Technology whitepaper.