To What Extent is CAD/CAM Technology Influencing the Construction Industry?
The construction industry relies on CAD models to provide designs of parts or components which are building blocks for an architectural project. Related to CAD models is BIM (Building Information Modeling), which is a multi-disciplinary and collaborative process. The purpose of BIM is to involve architects, engineers, and many other teams to work together in the construction of a building or architectural object. BIM’s collaborative process optimizes the design and construction process, because it provides significant savings in time and cost. The collaborative process also reduces design errors, minimizes design alterations, and minimizes rework.
BIM functions by importing information from different CAD systems in order to provide a cohesive database. The database provides information related to cost, scheduling, materials, building code requirements, manufacturers and vendors, assembly procedures, and other work processes. In order for BIM to be effective, it is necessary for design information to be transferable from different CAD systems.
Roles that CAD and BIM Play in the Phases of a Constructing Project
In order to determine the extent to which BIM is influenced by CAD/CAM technology, it will be helpful to look at the major phases of a construction project:
- The first phase involves planning, budgeting and obtaining permits: The planning phase involves evaluation of concepts and feasibility studies. For example, the construction of a school will examine the need and effectiveness of the school in the community, and where the school should be located. At this stage of the project, different teams involved in the project will work within their own CAD systems in order to come up with design concepts. It is not likely that mechanical designers, electrical designers, plumbing designers, and other design teams will be consulting with one another in the concept phase.
Budgeting addresses legislative approval, environmental impact, and setting aside contingency funds in the initial budget estimates.
- The second phase is the design phase: This phase requires collaboration between different disciplines in order to be cost effective, to save time, to minimize errors, rework, and alterations. The designers are engineers, architects, and other building teams such as plumbers, electricians, and HVAC engineers. These designers had been working within their own CAD systems in the planning phase. BIM technology pulls all the information from the design teams together into a coherent database, in order to optimize the design process.
- The third phase is the design evaluation phase: It is in this phase that the power of BIM is most effective. By requiring a multi-disciplinary and collaborative approach, designers are forced to talk to one another. The collaboration avoids design errors, makes it easier to perform cost estimation, and to smoothly transition into the construction phase.
- The final phase is the construction phase: If the prior phases were implemented correctly, it should be straightforward to issue construction drawings which have accurate information for the site plan, floor plans, foundation, and materials (with their suppliers). There will be accurate drawings also for mechanical, electrical, lighting, and HVAC systems.
Who are the Major Players in CAD/CAM and BIM Technology?
It is not within the scope of this article to mention all major players in CAD/CAM and BIM technology; therefore we shall limit ourselves to three players. The industry standard file format used to exchange data between different CAD systems is called Industry Foundation Classes (IFC). This is an ISO format, developed and maintained by buildingSMART®, which each player should support.
IFC makes it possible for a fully detailed CAD model for a refrigeration unit to be exported as a 3D representation, with text properties into BIM, so that the refrigeration unit is eventually placed within a building. Conversely, IFC makes it possible for a building structure which has been designed with an architectural CAD package to be exported as a 3D CAD model into a mechanical design. After the mechanical design model receives the imported CAD model, it can show staircases, HVAC ducting and other structural entities:
- The first main player is Autodesk®. Autodesk created IFC Open Source Export for Revit in 2011. Autodesk’s Revit products provide both IFC file export and import.
- The second main player is SolidWorks®. SolidWorks has supported IFC since 2009 for both export and import. Models created using SolidWorks can be integrated within other CAD data files such as Autodesk’s Revit or ArchiCAD.
- The third main player is ArchiCAD®, an architectural CAD system owned by Graphisoft®. ArchiCAD has supported IFC since 1996 for both export and import.
These three players are representative of leaders who can transfer CAD data into BIM technology.
As mentioned earlier, BIM creates a virtual construction document from all relevant CAD inputs.
Consider these benefits that BIM provides:
- It provides practical information which explains the meaning of drawings in CAD files. For example, a CAD file neither explains that a collection of lines represents a door, nor indicates where the door belongs in a building. BIM gives meaning to the lines as representing a door, and where the door is located within a building.
- It provides an integrated database of information about a construction project. The integrated database provides precise data on design, validation, costing, materials, construction details, and lifecycle maintenance.
- It provides details on budgeting, scheduling, workflow, and efficient use of manpower and resources.
- It provides real time collaboration and information sharing between disciplines, thereby creating savings in cost, time, redesign, and errors during the design implementation phase.
The extent to which CAD/CAM technology is influencing the construction industry can be summarized in terms of the benefits that BIM provides. It is probable that future releases of CAD software may incorporate some features of BIM. This would make CAD designers pay more attention to how a specific design interacts with other related designs, and how a specific design fits into the integrated construction plan.
CAD designs will always provide the building blocks for a construction project, and BIM will integrate CAD designs into a virtual representation of a construction project.
– The CAD Chief