What is a CAD software package?

Essentially, CAD software programs replace traditional draft­ing tools, and some would even argue sketching (although I still feel there is something magical about the process of putting pen to paper that can’t be replaced, but maybe I’m just a romantic). Those images from the ’50s of men wearing ties labouring in rows of drafting desks have been replaced with computers, servers and advanced human interface devices such as tablets and trackballs.

The term CAD refers to a broad range of software that can be used in any design profession: architectural, engineering, custom cabinetry or machining. Traditionally, you produce plans, eleva­tions, sections, details, etc. of your design, which then get printed or “plotted” on a large-format printer. You simply conform to the drafting convention that’s appropriate for your industry. Using CAD tools, you can design your project using the traditional two-dimensional (2D) projections or, more commonly now, model your design virtually in three dimensions (3D).

Once designed, these models can be exported into another cate­gory of software called Computer Aided Machining (CAM). CAM tools are different because their primary function is to produce machining instructions as a “code” file that will be uploaded to a Computer Numeric Controlled (CNC) machine to be fabricated. In essence, a CAD program will produce a drawing or model, while CAM is the next step to have your part manufactured or “machined.” We’re going to leave further discussion of CAM and CNC machines for now and continue to explore the nuances of CAD programs.

Common CAD characteristics

Most CAD programs have several common characteristics. They all use a Cartesian coordinate system, describing any point in space with an “x,” “y” and “z” value measured from an origin point. (Are you having math class flashbacks?) They also have simi­lar basic elements, such as a drawing area, an origin, toolbars and dropdown menus. Program functionality can be generally divided into three main areas: drawing tools (line, circle, ellipse, arc, etc.); editing tools (erase, move, copy, etc.); and management tools (layer controls, output parameters, etc.). Users generally find that once they have learned the basics of one program, it’s relatively easy to learn other programs.

There are generally two different approaches to CAD design. There is the traditional 2D drafting method used in the building industries and 3D modelling which is a more visualized approach to design. 2D CAD programs approach the technology as a sub­stitute for a pencil or pen. The viewer must be able to read the drawing and imagine what the design will look like. One of the most commonly known software packages utilized for 2D design is AutoCAD, which is produced by Autodesk.

Three types of 3D modelling

Programs for 3D modelling have been available for quite a while, however, they require enhanced hardware to run and more advanced training in order to operate. Today there are three com­monly used forms of 3D modelling that offer multiple entry points for users. The first and most rudimentary form of these tools is classified as “static” or “dumb” solid modelling. These utilize pre­defined 3D geometric solids (remember all of those wooden blocks from elementary math class?) combined and altered to achieve a design. These packages tend to require less hardware to run and are commonly hosted online, and feature databases of sample proj­ects and material palettes. A common and free online version of this type is TinkerCAD. This is perhaps the best entry point for a novice, or if you wanted to get kids engaged in designing their own woodworking projects. A good way to describe it to younger gener­ations is as “Minecraft with more shapes.” (For those of you who don’t play Minecraft, it’s an online virtual building game / environ­ment where everything is built from a single cubic unit.)

While most static solid modelling software packages offer an easy entry point into 3D modelling, there are also some highly specialized packages that take advantage of databases or “galleries” of models and allow users to specify set parameters. SketchList 3D is an exam­ple of one of these titles. Through an interface similar to other CAD software, you can design furniture and millwork from base designs modified to fit your specifications, such as dimensions and number of drawers, shelves, doors, etc. There is also an option to build your proj­ect from scratch using a palette of materials with predefined properties. Additionally, SketchList 3D also generates supporting documents like cutting diagrams, and parts lists and purchase lists.

The second type of 3D modelling is a hybrid of 2D and 3D mod­elling and is perhaps the most powerful of all the options. It has become commonplace in multiple industries. In essence, a designer begins with a 2D profile or “sketch” and then extrudes or sculpts the model to create the final form. One approach in solid model­ling is called parametric modelling. Using this technique, a running history of the development of a design is tracked, enabling you to go back and revisit an earlier stage of the process to make changes. Once completed, the remainder of your workflow will automati­cally update to reflect that revision. This feature is immensely powerful, because it permits a designer to revise or consider vari­ants quickly and efficiently.
The third technique for solid modelling is called “explicit” or “direct” modelling. It’s very similar to parametric modelling, except that it doesn’t track the design history of an object. This approach is commonly used for developing models with complex curvatures and forms. Most mid- to high-end software programs offer both methods and allow the user to select between the two modelling methods or integrate both into a single design.

• Another feature of most mid- to high-end 3D modelling pro­grams is the ability to automatically generate traditional 2D drawings of your model. The program may allow you to set your views or will have a series of pre-set viewing windows that automatically display your model. This leaves you to set the scale, dimension and annotate your drawing as necessary. In addition, your 2D drawings will update as you refine your model. With the development of these types of powerful applications, designers are increasingly beginning their creative process with a model, versus a traditional drawing.
  There are several software programs that support the 3D model­ling approach. Most are required to be installed on your computer; others are hosted in the cloud, while some are a hybrid of the two.

Common titles include:

• SketchUp
• SketchList 3D
• Onshape
• Solidworks
• AutoCAD
• Fusion 360
• Rhinoceros

Printing drawings

Regardless of the type of software you use, at some point you will want to bring your design into the shop. Traditionally, that meant printing it out yourself on letter- or legal-size paper or sending it out to a professional printer for a larger format, which increased the cost of a project. Regardless of the selected print method, one of the key tenets of drafting is the use of line weight to convey depth. For exam­ple, architectural convention has been that a floor plan is the rough equivalent to a section through the “x-y” plane, approximately 4′ – 0″ off the floor. Any material cut by that plane would be represented by a thicker line than an object that was located below that plane. In a 2D CAD environment, this is commonly achieved by assigning colour to specific drawing layers, placing the various elements of the drawing on the relevant layers (exterior walls, stairs, doors, fixtures, hatching, etc.). For efficiency, standard practice is to have a default layer configuration with the line type and colour included on a title block that you develop. This title block then becomes part of the ini­tial setup of your drawing. Then when you go to print, you assign a pen weight to a colour. General practice is that you would create a standard list of pen weights and then save it as a file and simply open it when you want to apply it to a drawing. If you are sending out for printing, you simply include this list of pen weights with your print order and your printer will be able to set those values for you.

With the development of smartphones and tablets the need for printed drawings has been reduced. Unfortunately, you still need them to apply for a building permit if that’s what your drawings are for. All programs offer you the functionality to print or save your designs in a format that can be visible on any smart device. Some of the programs even have dedicated apps that allow you to not only view designs, but also annotate or even edit them remotely. This can be a tremendous advantage when you’re in the shop and need to make a revision on the fly, or are visiting a site and need to record an as-built condition.

Licensing software has a variety of options. Some are 100% free (Onshape), while others offer free use with reduced functional­ity (SketchUp) and a purchase option for a full version. Some offer free trial periods, with full access (Solidworks), and some offer free use for certain user groups like hobbyists, educators or students (AutoCAD and Fusion 360). Even the price structures vary. Some offer a one-time licensing fee, or the most recent trend is to offer an annual or monthly subscription fee. Regardless of the fee structure, a single, non-commercial license ranges from hundreds of dollars into the thousands.

Why even bother with CAD?

So, why bother with all of this? Efficiency. If you invest the time to work out all of the details of your project virtually, it will pro­vide you with a better understanding of the intricacies of your design and help you to determine poten­tial problems and workflow. To aid you in this, CAD software can allow you the opportunity to:

• provide standardization across projects
• easily revise your project
• test out different materials for aes­thetic qualities
• produce animated simulations of projects (joint conditions or walk throughs)
• run engineering analyses such as resistance, curvature or sectional analysis
• access manufacturers’ databases of materials and fixtures (plumbing fix­tures windows, millwork profiles)
• insert and link spreadsheets of material quantities, cut lists, door and window schedules
• quickly communicate and collaborate with clients, consultants or contractors
• remote access to drawings via a smart device

The wood manufacturing and building industries have all moved to using these design tools in their operations. While you as a hobbyist may not have the same scope of work, there are distinct advantages to being able to leverage these tools in the pursuit of your passion.

Learning the programs

The next question is, how do I develop these skills? Depending on your preference, there are multiple ways to learn how to use these tools. For example, there are printed resources you can pur­chase and work through at your own pace. The downside to these is that they tend to be pricey and quickly become outdated as newer versions or updates are released.

Alternatively, there are in-person and online courses offered through local colleges. These typically run $200 to $500 for a course, and may offer you the opportunity to earn formal recognition.

There are industrial training providers as well that offer industry-recognized certifications or “micro-credentials.” These are typically self-directed and online with a licensing exam. These tend to be more costly because they feature proprietary curriculum and the opportunity for industry recognition.

The last, and perhaps the easiest, option is to search the software producer’s website for free online training material. Most vendors recognize the need to support users through the initial learning curve and provide resources to do so. However, once you get past the initial acquisition of skills, no-charge training materials for the more advanced features tend to be harder to find. This is where the online community really demonstrates the power of social network­ing. A quick internet search will generally result in a multitude of online content supporting your needs. These could take the form of social media groups, user forums, videos, instructional blogs or product reviews. As you can imagine, not all resources are created equal but, bearing that in mind, a good deal of my learning around new titles has been self-directed and has resulted in many success­ful projects.

There is a definite place for CAD tools in woodworking. As these technologies develop, the skill level needed to be successful is decreasing and the hardware is becoming less expensive. There are opportunities for all woodworkers to utilize some form of CAD system in their work. The biggest requirement is the desire to acquire a new set of skills.