CAD (Computer-aided design) has been used in the design industry for 30 years or more. It enables the fast production of drawings and the ability to revise designs or reproduce alternative proposals very quickly.
CAD has proved to be an essential tool in communicating designs to stakeholders, but the advent of new technology has raised client expectations and now drawings alone are often not sufficient.
Building Information Modelling (BIM) is one of these new technologies. Its primary focus is the development of buildings within collaborative working environments and has shown to be a game-changer in the industry. Measures such as the UK government BIM 2016 mandate and cloud computing have driven the BIM process forward.
There is a correlation between BIM and CAD but they are quite different. BIM is a process used for the entire life cycle of a building. 3D modelling is just a part of that and to add to the confusion CAD can be part of the BIM process too.
Here we look at the differences between CAD and BIM and how each is applied to the construction industry.
CAD has been around for a long time and used in the Architecture, Engineering & Construction (AEC) sector for about 30 years. It was designed and is used as a direct replacement for the drawing board. It enables faster production of drawings (Plans, Elevations, Sections and Details) and amongst its core strengths, certainly over hand draughting, is the ability to revise designs or produce alternative proposals very quickly.
CAD has proved invaluable on large projects where the requirement to bring design drawings together from different disciplines for coordination purposes is easily achieved and many on-site issues averted.
CAD has evolved over the years and now incorporates 3D functionality allowing users to develop complex projects and enabling a better understanding of design constraints and allow clients to more fully visualise the design.
Nowadays designs can go from preliminary concept design to on-site construction far more quickly than in the past.
CAD has been at the forefront of AEC design technology over recent decades but it has had its limitations, in many ways its success and the market dominance by a few companies has held the CAD process back. Some of the advantages and disadvantages of CAD breakdown as follows.
Building Information Modelling is a process or design methodology; it is not just another CAD tool. BIM was given a boost in the UK when the government mandated that from April 2016 every construction project funded by central government was to be delivered with ‘fully collaborative 3D BIM. Since the mandate came into force, there has been a rise in levels of BIM adoption.
In particular, the 3D modelling aspect of BIM makes good use of the cloud allowing all project members to collaborate with real-time ability to update the model, this allows for quick changes as required. When used at its best BIM aids the entire project team to visualise and analyse the project, spotting construction issues before reaching site.
Sustainable BIM methodology enables the design of every aspect of the building not just the building envelope itself. Mechanical, Electrical & Plumbing (MEP) features can be incorporated into the model and analysed for interference. Sun, shadow, heating and right of light can all be studied.
Used well, a 3D BIM model holds information about the building within the model for the lifecycle of the building.
BIM offers a more complete solution than CAD and addresses many of its issues but there are still some drawbacks.
CAD and BIM are different but exist in the same sphere. CAD is primarily used for the development of plans and some 3D models. BIM a methodology used in the creation of integrated models for use throughout the life of a building.
If you would like to learn more on this and how Benchmarq can assist you with you CAD and BIM requirements, please get in touch at [email protected].