Leveling up your CAD presentation skills: large projects and design reviews

So perhaps you've mastered the often challenging and sometimes humbling task of presenting your engineering design to others, whether they be your peers, your metric-obsessed, but overall supportive manager, or even an inquisitive buyer. But now replace your design with something much larger, involving dozens or even hundreds of other engineers. And replace your firm, but well-meaning manager with a hard-nosed VIP customer with a contract for millions, an unhealthy penchant for detail, and a severe case of jet lag from hopping over the pond for the third time this month. You're going to need a whole different kind of plan.


It's no longer about you

Few things worth designing and building these days are the work of a single individual. It's often an orchestra of engineers operating in concert – the more complex the product, the larger the orchestra. But when you want to examine how the music is flowing together, considering all the notes and all the instruments, you need a methodology to sample the whole of the orchestra without the cacophony of talking to everyone at once.

Hence, we have design reviews. Whether it's the first introduction of an end-to-end concept in a Preliminary Design Review (PDR) or making sure requirements are met and all concerns have been addressed in a Critical Design Review (CDR), the underlying approach is the same.

The right stuff

You might be inclined to believe that such high-level reviews must be the sole burden of the higher-ups, with project engineers and the program management office sealed away in a conference room with a customer for days at a time, in mortal struggle to outlast mutually assured destruction by PowerPoint. But in reality, design reviews have the interesting tendency to swing from broad overarching themes to very specific details. And often that requires a deep dive into the design and consequently the 3D model to hash things out.

But calling in individual engineers in a large project both wastes time and ignores a harsh truth: many engineers suck at communication, and that's a huge liability in front of a big customer. In such a context, an engineer is not representing just a design, or even a department, but a whole company. Those are big shoes to fill.

The solution is to find the right engineer who can both drive the CAD well and has the necessary speaking skills, and charge that engineer with maintenance of CAD assets for design reviews. That responsibility includes not only maintaining a top-level assembly model, but also validating that any presentation slides used throughout the review are reflecting the most up-to-date configuration.

It can be a daunting task. Sometimes it's a two-man combo: one to drive, one to speak. But more often, it's one lucky engineer. And that lucky engineer just might be you.

Large model management

As project size increases, coordinating work becomes more difficult, and visualizing the overall product within the CAD environment becomes significantly more challenging as assemblies balloon to tens of thousands, hundreds of thousands, or even millions of parts. So if you think you're just going to waltz in the design review, click File-->Open, and load the whole top assembly at once, you'll be on the express train to fail town, population you.

Viewing data within a narrow context is essential. And the responsibility to make that possible has to be attended to regularly, throughout the project. Some tips about what can be done to ease the management burden:

  • Use CAD tools for large assemblies: Most modern CAD platforms have features available for managing large assemblies including partial loading on a variety of parameters including defined spatial volumes. Study up on these features to keep the relevant details up on the screen as needed.
  • Drop the hardware: Rarely are fasteners and small hardware relevant to design review discussion, best to leave that level of detail out of your models (or otherwise unloaded or suppressed) to keep your CAD station from taking a serious geometry beat down.
  • Lightweight representations: For assemblies of extreme size (i.e. 100K+ parts) even the best assembly model management may prove insufficient, necessitating 3D viewing with lightweight representations (such as JT) in an external viewer. Such presentation maintains most of the fidelity of the original model, but has dramatically lower memory requirements.
  • Keep notes about each relevant assembly: Especially when presenting other's work, have notes to remind you of any important facts and or design information. No matter how smart you are, you're not going to be able to remember it all.
  • Get everyone on the same page: Make sure the subassemblies that feed into a master assembly follow some sort of CAD standard, and that the standard has provisions in how assemblies are setup to make your life simpler in maintaining the master model.
  • Version control in a PDM/PLM environment if available: It'll save your bacon when it comes to version controlling a large amount of subassemblies. In fact, it'll save your complete breakfast.

Don't forget your ten-gallon diplomacy hat

The last bit of advice is you'll have to turn your coping mechanism up to 11, knowing that much of the input you may receive will be infuriating or just plain disruptive.

When a VIP customer is present, special handling is required. Keep in mind they will be mostly cordial, but they don't particularly care about you. You're barely on their radar. To them, you might seem like an ant peering out behind a tiny CAD workstation, trying to question the universe. And how guilty would they feel if they crushed said ant? Not all customers are so malevolent, but when millions of dollars are at stake, and strong Type A personalities are on deck, expect there to be some tension, and yes, occasional drama. Let your PMs navigate the conflicts. You're there to deliver technical expertise.

There's obviously lots to worry about, but nothing much to fear. With the right preparation you can wow the crowd at a design review. Now's your chance to shine. Good luck.


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