Digital Design Tools
Computers and digital technologies have advanced rapidly in the past 50 years, and they now infiltrate almost every aspect of our lives. So, also in woodworking, computers have taken root in the design and planning stages of our projects. Computer aided design (CAD) software packages are the digital tools most designers have adopted. It’s with these types of software that we will begin to explore how the digital revolution has begun to change how we spend time in the shop. In two future articles we will explore additional forms of advanced technology in the shop: lasers and 3D printing.
As a construction technology teacher, I have instructed more than 1,000 youth and adults in woodworking techniques over the years. It has been my experience that one of the most underappreciated phases of a project is the planning phase. We are so anxious to get into the shop and see our visions become reality that we may not afford the planning stage the necessary time it deserves. Early CAD programs didn’t help this issue. They required huge investments of time to learn and significant costs to license and upgrade hardware to properly run them. Today’s CAD systems have made huge gains in these areas. The reason for these gains could be due to several factors: an increase in computer literacy; more user-friendly software programs; incredible advances in hardware; and, most significantly, with the development of the web, we have new ways of accessing technology and sharing resources. Regardless of the reasons, as woodworkers we get to reap the benefits.
Typical CAD Display Elements
All CAD programs utilize similar program structures. They feature a drawing pane, an origin, toolbars and dropdown menus. AutoCAD model display is shown here.
This screenshot of a cedar and pine storage bench in AutoCAD currently has all the dimension and drawing layers turned on.
Fusion 360 Screenshot
A pine cabinet with all the components of the project are shown here in Fusion 360.
In this screenshot, SketchUp is being used to draw a small building.
SketchList 3D Screenshot
SketchList 3D offers a database of designs that can be altered to fit user specifications and generate material lists, cutting diagrams and shop drawings.
Here, an LCD monitor is being drawn in Solidworks.
Basic Geometric Shapes
A few of the basic 3D shapes that are utilized in “dumb” 3D modelling. A screenshot of Tinkercad desktop is shown here.
Parametric Modelling Timeline
One of the key features of parametric modelling is the ability to track a model’s progress and “roll back” to an earlier stage to edit details. An example of a parametric timeline is shown here for a T-nut knob project, shown in Fusion 360.
Sketch of a T-Nut Knob
Most parametric models start with a 2D sketch, such as this sketch of a knob for a 1/4-20 thread T-nut done in Fusion 360.
Application of 3D Characteristics
Once a sketch has been developed, 3D characteristics are applied by adding or subtracting: thickness to a profile; fillets; chamfers; lines of symmetry; etc. With this T-nut knob, thicknesses and fillets have been added in Fusion 360.
Mesh Body 3D Model
3D modelling programs allow you to sculpt complete curves using mesh bodies. This technique has some similar techniques as conventional modelling, however, it also has unique commands that allow it the flexibility to create complex curves and planes. A Fusion 360 sample file is shown here.
Colour Determines Printed Line Thickness
The line weight of a drawing is commonly determined by colour. Shown above is an example of a drawing where elements are defined by layer and colour. On the left is how this will appear when printed.
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.
Common titles include:
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:
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.