MBD and 2D Drawings: The Skill Burden Outside Engineering

This post contrasts the skill burden of 2D engineering drawings and model-based definitions on non-engineering hiring and onboarding.

As you may or may not know, we’re getting very close to formally starting our newest research study: The Model-Based- Definition Supplier Readiness study. As part of that effort, I’m revisiting some of the areas where organizations should get value out of such an initiative. Because this study looks at how suppliers use MBD in manufacturing, procurement, tooling design, inspection and engineering change, I thought it would be important to compare and contrast the skill requirements needed to work with 2D drawings and MBDs for those outside engineering.

The Three Orthographic Views

Before we get into required skill sets, we’ll start with how the 3D shape of a component can be gleaned from a 2D drawing. It all starts with the traditional three orthographic views. I’m going to rely on the definition we set out in our ROI of MBD Research Report from early 2017.

To convey the complete and detailed geometric form of a component, a drawing relies on a combination of 2D entities, dimensions and multiple views. In a single view on a drawing, 2D entities and dimensions convey the detailed form or shape of a component. The combination of the traditional three views of a drawing and its dimensions conveys the complete detailed form of a component.

The effort to define the measures and thresholds within which a component meets quality standards partially builds on the earlier efforts to convey the complete and detailed geometric form of a component. Dimensions already exist that define the component’s form. However, not all processes use all of those dimensions to measure conformance to quality standards. Therefore, dimensions should be explicitly identified for measurement once the component is manufactured. Tolerances must be added to the existing dimensions or geometry on the drawing to define the threshold within which those dimensions must fall.

Extrapolating a 3D Shape from 2D Views

We need to understand the 3D shape of the component because we need to make or source the part as well as inspect the part to ensure it matches the original intent of the engineer.

To understand the 3D shape from the drawing, an individual has to extrapolate those three orthographic views in their mind to construct the 3D shape.

This means that not only must everyone in engineering be able to perform this task mentally, but also every downstream consumer of that documentation.

Defining Spatial Intelligence

Back in 1983, a scientist named Howard Gardner developed a theory that there is not one form of intelligence, but nine of them. I’ve detailed them out and their relevance to engineering in a post called Multiple Intelligences and the Engineer. Here’s the relevant definition of spatial intelligence from that post.

This area deals with spatial judgment and the ability to visualize with the mind’s eye. Careers which suit those with this type of intelligence include artists, designers and architects. A spatial person is also good with puzzles. Spatial ability is one of the three-factor’s beneath g in the hierarchical model of intelligence.

This seems like the exact match in terms of a skill required to extrapolate the 3D shape of a component from the three orthographic views on a 2D drawing.

Now, I’ve talked about how low intelligence in this area can be an impediment to using Mechanical CAD. However, in this post, I don’t want to dive into the relevance of spatial intelligence in engineering, I want to talk about its pervasiveness of spatial intelligence outside engineering. Or, at least, perhaps talk about the pool of candidates you can hire.

2D Drawings, Spatial Intelligence, Hiring and Training

OK. How common is high spatial intelligence outside engineering? Some might say that those with high spatial intelligence are attracted to roles like engineering, architects, designers and the like. But, for the sake of the argument here, let’s assume that there is an even distribution of this intelligence across the population and roles. So someone is in procurement, manufacturing, and quality are equally as likely to have a high spatial intelligence as engineering. Most would likely say it is lower. But let’s assume it is equal for now.

Now, if are in an organization that requires some interpretation of drawings, then one of the skills those roles needs is at least average spatial intelligence. When you go to hire someone, you automatically are working with a smaller pool of candidates. That makes it harder to fill jobs. When someone leaves or retires, it makes it harder to replace them.

Furthermore, even if spatial intelligence doesn’t explicitly affect hiring requirements, it definitely affects training. Because of this technical need, the onboarding process can take much longer. It can be months before an employee can be fully effective.

When it comes to spatial intelligence, I get it: its a badge of honor. Engineers and other technical roles can, and should, be proud of their ability to visualize something in their head. That’s great. However, realize that high spatial intelligence requirements for non-technical roles are a constraint on the organization’s ability to function. That makes it harder for everyone to do their job.

Interpreting Model-Based Definitions

OK. So how and why are MBD deliverables different? I’m going to rely on the definition we set out in our ROI of MBD Research Report again.

The means by which a 3D model conveys the complete and detailed geometric form of a component sharply contrasts with that of drawings. The geometry of the model inherently defines its form. No additional dimensions or information is needed to fulfill this function of engineering documentation.

That inherent form, however, does not satisfy the need to define the measures and thresholds within which a component meets quality standards. Therefore, dimensions must be added to the 3D model to define what must be measured to assess its conformance. Furthermore, tolerances must be added to those dimensions or the geometry to define acceptable thresholds.

MBD, Spatial Intelligence, and Hiring

What is the spatial intelligence requirement to interpret an MBD deliverable? It isn’t eliminated. Yet, I’d argue it is far lower than the ability to interpret a 2D drawing and reconstruct a 3D shape in your head. There is no extrapolation needed. The 3D model can be spun and interrogated.

In turn, that means there are lower requirements for hiring and training. That means it is easier to find candidates that could be effective in the job. That means the onboarding ramp is shorter.

Takeaways and Conclusions

  • Spatial Intelligence describes an individual’s ability to interpret and construct shapes spatially in their heads.
  • Individuals must interpret the three orthographic views on a 2D drawing to visualize a component. For non-engineering roles, this is a complex job requirement that can constrain hiring and lengthen onboarding.
  • With MBDs, the spatial intelligence requirements are far lower, because the 3D model is easier to interpret. As a result, hiring constraints can be eased in this area. Onboarding can be shorter.

That’s my take folks. I know there are some ardent anti-MBD folks out there who will disagree with me here. But I see this as a logical benefit of this kind of initiative. No matter where you fall on this matter, I’d love to hear your thoughts. Sound off in the comments.

Need more MBD guidance like this article?
Join our newsletter community for more.


When it comes to the value of Model-Based Definition initiatives, there’s lots of heresay and little evidence. That’s why Lifecycle Insights conducted a study and published the results in a research report.

Chad Jackson is an Industry Analyst at Lifecycle Insights and publisher of the engineering-matters blog. With more than 15 years of industry experience, Chad covers career, managerial and technology topics in engineering. For more details, visit his profile.