What is the definition of 2D drawing

Why engineers still create detailed 2D drawings.

Designing has been an integral part of practically all of engineering history. Before complex CAD technology, creating 2D drawings was essential for manufacturing and production was essential for creating products. Today, in a world with CAD to CAM and advanced manufacturing techniques, many of what we design have evolved into today's almost optimized state. However, one thing is still there and that is the existence of 2D detail drawings for parts, components, and assemblies.

CAD has allowed us engineers to spend less time refining the 2D detail drawing, but it hasn't eliminated the use of those drawings in industry. The advent of computer design brought about an influential change in the field of drawing. As CAD got better and better, we made a 180 degree shift to first design the 3D model and then detail the parts in 2D.

This was the first linchpin where 2D drawings became less important in the design process, but are still essential to the entire work of an engineer. 2D drawings have become significantly less important, but they haven't completely disappeared. With that in mind, we need to examine why these 2D drawings still exist and see if we can in any way optimize or reduce their usage to improve our workflow.

The course of 2D construction drawings.

Before we can understand how 2D drawings may or may not fit into the life of the modern engineer, we must first look at their history in the field of engineering and construction. Most engineering drawing techniques go back thousands of years. Perspective drawing was invented in the 1300s, descriptive geometry in 1765, orthographic projection in 1770, and 2D CAD in the 1980s. All of these developments led us into an age of rapid development in technical documentation.


Before computers existed, 2D drawings were used to fully define the specifications of a component. 2D drawings were used as the sole reference when creating a product such as a screw or a fitting. This production method essentially goes back to the beginnings of technical information. Its history speaks for its importance. For millennia, 2D drawings were the only carrier of design information - and then came CAD.


Initially, 2D CAD programs simply accelerated the process of creating these design drawings. These programs also made it easier to make design changes and greatly improved technical workflows. When the 3D CAD programs emerged in the 1990s, work processes and designs were also improved. But even with 3D capabilities, 2D drawings were the primary vehicle for a design into a manufacturing environment. For most of the existence of modern design, perhaps until the last decade, 2D drawings have been essential.


With increasing digital and robot-assisted production, the change from 2D to 3D information transfer has finally become a reality. It has brought us into a new sphere of making things just within the last decade. There is no longer a machinist who refers to a 2D sheet set. If there is a machinist at all, he will refer to a dynamic CAD model in most applications or he will program his machine with the help of CAD / CAM software. The information conveyed in construction has changed for the better due to the integrated digital revolution, but the 2D drawings remain in our work processes.

New manufacturing processes.

As an engineer, you probably understand just how advanced modern manufacturing has become, different from the workflow itself just a decade ago. Additive manufacturing is usually the new, trending manufacturing technique that everyone is talking about is changing the field of design. While additive manufacturing is making big changes and making most 2D drawings completely redundant, this new technique hasn't brought about the biggest changes.

Perhaps the biggest change in technical design is the slow, incremental technological improvement in manufacturing techniques. Methods such as CNC machining and other subtractive forms of manufacturing. These manufacturing processes used to be completely analog and require the input of an experienced craftsman in order to achieve a high output. This need for human control is largely why we as engineers had to create 2D drawings.

New subtractive machines still require human input, but on an entirely digital level. A machine operator in modern manufacturing works much more with CAM and HSM programming than he would ever do with paper data sheets. CNC machines are programmed today, they are no longer controlled manually. All these new manufacturing processes raise the question: If machines can work entirely from 3D CAD models, why do we still produce 2D drawings afterwards?

Engineers have data.

As we continue to analyze 2D drawings and figure out where they will fit into our design process, if they should fit at all, it is important that we define exactly what needs to be communicated in modern engineering design.

Since most products are manufactured in the digital domain in modern technical workflows, there is an abundance of data about a particular part. In previous 2D or isometric drawings, the data that could be extrapolated from the finished design was limited by what the engineer decided to include on the final data sheet.

Now drawings and drafts are largely communicated via digital areas. Think about how far cloud-based CAD has brought our ability to share and disseminate design data. CAD-to-CAM functions have made communication between departments seamless. Most of our technical data is no longer transmitted through static drawings.

Our 3D models that we design contain even more data than they did 5 years ago. We are able to include lattice structures, complex material data, infinitesimal dimensions, scaling data and interface data. For all practical purposes, a 3D model in CAD can numerically tell us more about a component than the actual part could ever do. So when we hand over a completed project in the form of a digital draft, we give the machinist, the production engineer, the production plant far more information than we could ever give them on a laboriously laid out set of sheets.

Engineers have always had data, what has changed is the way we express it. We often fervently oppose changes in workflow. Although we have embraced the evolving world of computational design, it seems that the only thing left from the engineering past is 2D drawing.

Are we making drawings for what is needed in the production pipeline, or are we just doing things like we've always done?

Where 2D drawings fit.

Our answer to the question of how 2D drawings fit into the design space falls somewhere between "Get rid of them" and "Keep them right where they are." Anyone watching the changes that have been taking place in the manufacturing world will likely find that the usefulness of 2D drawings is diminishing significantly from year to year. We can also understand that while there appears to be a downward trend in the usefulness of 2D drawings in engineering, that at some point we will reach an asymptote that is likely to be above zero.

At this point, 2D drawings will still be relevant and useful in some ways, but the time we spend perfecting them or communicating information about them will be as little as possible. So where is this asymptote and where should 2D drawings end up in our design space now?

These drawings were used in the past to communicate the large amount of data at the part level. Since most of this data is now transmitted via CAD models, the only data that must be transmitted at the part level is classified as critical. 2D drawings for parts only need to communicate critical information about a part that can be gleaned from a quick glance. The balance can be struck by asking, "What would take more time to look at the CAD model or look at a datasheet?" If critical data can be conveyed quickly through a 2D drawing without a CAD model needs to be called and measured, then this should be the case. This is exactly where the balance lies.