CAD
Computer Aided Design / Drafting
Computer – A machine that replaces the job called Computer who makes complex calculations
Aid – help or Support
Design – Drawing that fulfill a purpose
Drafting – Drawing has dimensions and notes to recreate easily as same
Summary
Computer Aided Design Software is a Computing software which is used to aid in the creation, modification, analysis, or optimization of a design.
Example : Solidworks, Creo, Inventor.
Computer Aided Drafting which includes the process of creating a technical drawing with the use of computer software.
Example AutoCAD, Microstation
BIM
Building information Model
Building – a structure with a roof and walls, such as a house or factory.
Information – Data
Model – a thing used as an example to follow or imitate.
Summary
BIM software – Software which creates a building/place model with the data in it.
What i might wish to show you is that BIM isn’t a suddenly emerged monster but the road from CAD to BIM is simply a natural thanks to go. In the late 80’s, thanks to advancement of special effects , the AEC industry began to adopt 2D CAD to exchange hand-drawing for creating engineering drawings. The fundamental 2D representation of engineering information remained an equivalent but only the tool was changed to 2D CAD software on a computer. So, we can say what 2D CAD did was just digitization of engineering drawings.
Later on, when 3D CAD was introduced, an architect was ready to use it as a design tool to precise his or her design ideas directly during a virtual 3D space.
The representation was not limited by 2D media. However, for building and civil engineers, the planning task is quite geometric shapes.
Therefore, 3D CAD was still not a sufficient design tool for engineers although it had been helpful. In the 90s, some research efforts initiated from Stanford University started to promote 4D CAD applications.
4D CAD integrates 3D CAD model components with their corresponding time or schedule related information during a AEC project to simulate the development process. It helps to facilitate team coordination, reduce design and construction conflicts, and support better decision-making with information visualization both before the actual construction work starts and during the construction.
Later on, people started to add more dimensions on top of it, for example, adding cost related information to create 5D CAD. Although 4D CAD is extremely helpful, the development of a 4D model by linking geometric entities with their corresponding schedules may be a very labor intensive and time consuming task.
In early 2000, BIM was emerged as a replacement technology within the AEC industry. It is a model-based approach to provide the industry a better way of managing engineering information needed for collaboration and decision-making throughout the lifecycle of a built asset. With the BIM technology, we will perform virtual construction within the digital space first.
Once we are satisfied with the planned process and outcomes, we can then engage in real construction. As you’ll see here, the important construction should follow alright the virtual construction. In the BIM approach, engineering information are managed within the digital model. This model consists of elements like unique real objects or components within the physical world.
Unlike the information management in traditional 2D drawings, this model-based approach significantly improves the consistency of information management, especially those related to product information. Nowadays, if you modify a 2D drawing, you need to make sure all other related 2D drawings are also modified accordingly to maintain information consistency. This is not an easy task because it is a human task and the relationships of drawings can be quite complicated, especially in a large project. In the BIM approach, the knowledge is managed within the 3D BIM model and every one needed 2D drawings are automatically generated by the pc . Therefore, any modification within the BIM model are often easily updated to the related 2D drawings. Since the introduction of construction management in late 80s, management of process information in the AEC industry has been significantly advanced. However, management of product information has long been hindered by the limitation of 2D drawings. Without a better way to manage product information, the advancement of construction management is also constrained. Now, with BIM, there’s little question a way better product information management is supported and a far better process information management will come. To the AEC industry, this development may be a new one. But if we take a glance at the manufacture industry, we will clearly see that the manufacture industry continues its journey from geometric CAD modeling to BIM-like object-oriented and feature-based modeling in the 90s and beyond. They are now talking about Industry 4.0. In this sense, the AEC industry is following the manufacture industry’s footsteps and that is why I said “BIM is a natural way to go” although we have no control on its pace.
Is BIM an evolution or a revolution? I would say BIM is an evolution from the viewpoint of advancement of the AEC industry in adoption of information technology and management technology. And, BIM can be a revolution because it is a paradigm shift and opens a door for revolutionizing the business models in the AEC industry. So, i might say BIM may be a “Revolution in Evolution”.