CAD DRAFTING

Imagine being able to walk through your new home or office building, go into every room, try out different colors on the walls or make changes to the design – before it’s even built. It sounds pretty amazing, and it is. That is the world of CAD (Computer-Aided Design) drafting.

Not too long ago you would find the designer or architect bent over a drafting table using a pencil, ruler and eraser, slowly drafting every detail by hand. Today’s designers use sleek, super-fast computers and CAD software systems that can quickly and perfectly create, edit, then display finished projects in breathtaking 3-D computer renderings. 

There are other software systems with similar acronyms, but they are essentially the same application with subtle differences in function. Two of these other systems, CADD (Computer-Aided Design and Drafting) and CAID (Computer-Aided Industrial Design) are the most commonly used. 

From the minute you get up in the morning, almost everything you will see or touch or use during the day had its beginnings as a CAD drafting project on a computer somewhere. Your car and every part in it, your electronics, furniture, your home and office, even your deodorant jar and the packages your food comes in were more than likely drafted using CAD.

The History of CAD

Like most great inventions, CAD drafting had humble beginnings, but the potential was immediately apparent. Software companies and thousands of dedicated developers and programmers saw that potential and have worked tirelessly for over 30 years now to develop and bring CAD drafting programs to where they are today. The results have been no less than spectacular.

 

The initial developments that led to today’s CAD programs were first carried out in the early 1960’s and 1970’s in the aerospace and automotive industries. Both industries were independently developing the first CAD systems. Most people agree that the real breakout point was the development of SKETCHPAD at MIT in 1963. The main feature of SKETCHPAD was that it allowed the designer to work with the program by drawing on the monitor with a light pen. This was essentially the first GUI (Graphical User Interface) and is the most

The first programs were only available to large corporations in the automotive, aerospace and electronics industries. These were the only companies that could afford the expensive computers and computing power needed to do the calculations needed to run the programs. The leaders in developing these first programs were GM, Lockheed and Renault.

The first CAD programs in the 1970’s were only capable of creating 2D drawings similar to the hand-drafted drawings of the time. But even those first simple programs were changing the face of manufacturing and construction design. The programs quickly evolved over the years as computer processing speed and power and graphics capabilities increased. In the 1980’s the next major step toward modern CAD was achieved with the advent of the ability to do 3D solid modeling.

In 1981 two solid modeling packages were released- Romulus by (ShapeData) and Uni-Solid by (Unigraphics). In 1982 John Walker founded Autodesk which developed one of the most famous 2D CAD programs, AutoCAD. In the late 1980’s and early 1990’s the solid modeling kernels for rendering 3D designs were integrated into the new CAD programs for the first time.

 

As computing prices came down, so did the potential and the promise of CAD drafting for smaller companies. This now made it possible for any company to afford a high-quality CAD design program. The 1990’s saw the release of some of the most popular mid-range packages. SolidWorks was released in 1995, SolidEdge was released in 1996, and IronCAD was released in 1998.

 

Different Types of CAD Systems

Most CAD computer workstations are Windows-based PCs with some running on Unix and a few on Linux machines. Usually no special hardware is needed except for a high-end OpenGL Graphics card for renderings. Also, more is always better when it comes to computing power. A machine with dual-processors and massive amounts of RAM is needed for maximum performance on complex projects.

CAD systems can be separated into three different types: 2D drafting systems like AutoCAD LT (also known as Autocad “Light”); 3D solid feature modelers like Architectural Desktop, Chief Architect, ArchiCAD, Alibre Design, VariCAD SolidWorks and SolidEdge; and high-end 3D hybrid systems like Pro/ENGINEER and NX (Unigraphics).

 

The human interface is usually a mouse but a trackball or pen and tablet can also be used. The model can be manipulated and viewed from different perspectives and angles. On some systems you can even use stereoscopic glasses for viewing in true 3D. 

Today there are many low-end 2D systems available and even a number of free and open source programs. All these programs provide an ease of design not possible with hand drafting on a traditional drawing sheet. For example, in 2D drafting a wall in a house would be drawn as 2 parallel lines spaced a certain distance apart, say, 6 inches. To insert a door into the wall, you would follow a process similar to manual drafting- you would first erase part of the wall, then draw in the lines representing a door. In 2D, each line is inserted manually into the design. The end design has no mass properties and you can’t add features such as holes, etc. directly. 

With a basic (low-end) 3D modeling program, to draw that same wall you would not have to draw individual lines- instead, you would click on an icon for the ‘draw wall’ command and use your mouse (or trackball) to specify the length and location. To insert a door, you simply specify the size and location of the door- the software automatically erases that portion of the wall where the door goes. Over the course of designing an entire house or building, tools such as these can save countless hours. You can then use the solid model to generate views of the project from any viewpoint or angle- something that 2D programs cannot do.

 

3D parametric solid modeling represents the high end of CAD. With 3D parametric solid modeling programs such as Alibre Design, Solid Works and Solid Edge, the designer must use what is called ‘design intent’. This means that the design has to be thought of as a real world representation of the object. You are able or unable to make changes to the object the same way you would make them to a real world object. Therefore, parametric solids require the designer to think ahead and consider his actions carefully.

 

The top-end systems include the ability to add more organic aesthetics and features to the design, such as photorealistic colors and surface textures. Surface modeling combined with solid modeling is used to create most day-to-day products for consumers. 

The CAD designer should be forward-looking as he designs and the objective should be to make future work on the design as easy as possible. This means the designer needs to have a firm understanding of the system being used. A little extra attention and careful planning in design now can save a lot of grief later.

 

In the late 1980’s the advent of affordable CAD programs that ran on desktop computers led to downsizing in the drafting departments of many small- to mid-sized companies. Typically one CAD operator could replace three to five drafters using traditional drafting techniques. Also many engineers opted to do their own drafting work which eliminated the need for dedicated drafters. 

This phenomenon was also reflected in other areas of the typical office. As word processors, databases, spreadsheets, etc. became the norm, many jobs were eliminated as multiple functions across several jobs could now be done by one person on a single computer.

 

The adoption of the CAD studio, or as it is also called ‘paper-less studio’, in design schools was met with major resistance. Teachers were afraid that designing and sketching on a computer screen could not duplicate the artistry of traditional sketching on a drafting pad. Also, many teachers were worried that students would be hired, not for their design skills, but for their software and computer skills. Today CAD is recognized as an essential design tool and is taught across the board in architecture schools.

It is interesting to note that not all architects have joined the CAD bandwagon. Australian architect Glenn Murcutt, winner of the 2002 Pritzker Architecture Prize, has a small office with minimal CAD capability.

 

Different CAD Industries

CAD drafting is now used in all phases of design across all industries. Specific industries have developed specialized applications of CAD systems. Below are some of the main industries using CAD and their related CAD applications.

The AEC (Architecture, Engineering and Construction) Industry
• Residential and Commercial Architecture & Design
• Landscape Architecture
• Structural Engineering
• Construction
• Civil Engineering
• Mapping and Surveying
• Highways and Roads
• Water and Sewer Systems
• Factory Layout
• Industrial Plant Design

Mechanical (MCAD) Engineering
• Aerospace
• Automotive
• Machinery
• Consumer Goods
• Shipbuilding
• Biomechanical Systems

Electronic Design Automation (EDA)
• Electronic and Electrical (ECAD)
• Digital Circuit Design

Manufacturing Process Planning

Industrial Design

Apparel and Textile CAD
• Fashion Design

Entertainment
• Computer Graphic Animation (CGA)

CAD Drafting Today

One of the major advantages - and one of the biggest payoffs - of CAD drafting today, is the reduction in design time and therefore the amount of money it can save on a project. In manufacturing, CAD drafting helps keep design costs down which translates into cost savings for the consumer. 

In residential or commercial design the amount of time saved can be enormous. As an example, let’s say you are looking for a designer or architect to design your home. The designer can create a design: (a) from scratch based on your idea or concept; (b) from photos of actual houses; or (c) based on a previous design which can be easily modified in CAD. 

CAD design companies will typically have many different home or building designs available to choose from. It is easy for a client to look through the designs then select one they like. They can use the design as-is or easily customize it to their own tastes. Clients can even take design elements from different projects and combine them to create an entirely new home or building. The possibilities are endless. 

Making small changes to a CAD design- for instance, moving walls, windows or even whole rooms- typically takes minutes or hours, not days. This would have been a huge and very expensive task in the days before CAD drafting. 

There are many CAD design companies that can serve your residential or commercial design needs and many of them offer complete project management as well as design and drafting of the project. 

CAD drafting will no doubt continue to evolve and become more powerful, and remain, next to the computer, as one of the most important technological developments of our age.