Green Lines on Black: The Day CAD Showed Me Why Thinkers Finish First

The race is not won by the rabbit.

May 06, 2026

When I was learning CAD for the first time, it was a new technology. I learned on Harris CAD. It was 2D drawing on a CRT with green lines on a black background. Ancient compared to now, but it was amazing in its day. I was in my last semester of engineering school, and ironically I had completed two semesters of Engineering Drawing, with T-squares, two triangles, and HB pencils, as a requirement, three years prior.

Our big final project was to draw a three-shaft, four-gear gearbox in the conventional three-plane views and have the drawing fully dimensioned. We had to draw the correctly sized gears, bearings, shafts, casing, enclosed lid, and all the necessary assembly hardware. We would have to match our design to a given set of shaft input and output speeds, and input and output torque loads.

I had worked as an auto mechanic at two different shops that specialized in British cars. I drove a mechanically challenged British car as a daily driver. And I currently worked at the school’s flight research laboratory as a mechanic, machinist, welder, and composite fabricator. So I had a lot of experience assembling and disassembling a wide range of mechanical machines.

I had already completed two semesters of Machine Design as part of my Mechanical Engineering degree. I knew how gearboxes worked and how their assembly and disassembly happened in real life. So my first major CAD project did not seem like much of a challenge.

There were only a handful of CAD stations and twenty-five or more students trying to use them. We were given two-hour time slots, twice a week, to work on the drawing each week during the semester.

We had to do the machine design calculations to size the hardware needed to carry the torque and speed loading. Then select the proper bearings and gears out of wide parts catalogs. Use the dimensions from those catalogs to help size the needed assembly spacing. Then design a case and cover lid to fully house the sub-assemblies. We also had to select the fasteners, washers, and C-clips needed to construct the shaft sub-assemblies.

This really was the culmination of learning to CAD while demonstrating our Machine Design skills. There was no manual to teach us how to CAD, and there was no manual on defining all the steps necessary to design a workable gearbox either.

So as motivated and learned students quickly nearing graduation, some of us jumped in and started drawing and some of us sat back and did some thinking.

I took this challenge on as a thinker. I knew in all our prior lab courses my fellow ME students dragged their feet and waited to the last minute to get to work, so I knew that the last minute was not the time to learn how to draw on a new system I never used. I was also familiar with understanding how a gearbox worked and I had used parts catalogs in the past to buy gears, bearings, keyways, washers, and fasteners.

My plan was to learn how to draw in CAD during the first week by using mine and everyone else’s time slots, if they did not show up for their scheduled time allocation. Not many showed up the first week, so I had about ten hours of learning how to draw points, lines, curves, plus mastered trimming and line extension features. And I also learned how to edit and resize shapes and add in detailed features like keyways and grooves for C-clips.

With that goal met, I drew a plain box and a set of circles and shafts that matched the number of gears and shafts that would be eventually needed in the three views required for the assignment. I knew if the hardware already existed in some near realistic shapes, I could quickly edit and resize them later when I had the final parts selected.

The second and third weeks were dedicated to doing the necessary machine design calculations and selecting my properly sized catalog parts.

By the fourth week all the parts were selected and sized, and then I broke out the T-square and triangles and made a dimensionally correct pencil drawing of the assembly in the three views required in the assignment.

The fifth week I used my assigned CAD time slots to do the final edits on the parts and I was done. By that fifth week the panic had set in on those that had not learned how to draw and some were still learning how to properly select an existing gear or bearing when it did not exactly match your calculated sizing needs.

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I tell you all this, because while I worked at the school’s flight research laboratory there were two full-time A&P mechanics that were certified to work on aircraft. They were the local supervisors that I and the other student employees were assigned to work under. They led the various teams working on a range of projects and ensured the planes, gliders, and drones we worked on and flight-tested remained safe and operational.

For reasons I never fully understood the two A&P mechanics did not get along and so they never worked on the same project together. They were professionally polite but they had completely different working styles.

Bob started his day with energy and would dive in and get to work each day. Ray would sit and drink his coffee and make some notes each morning and then head to his tool box and select his tools and load up his work cart with fasteners or grease tubes or other necessary items.

Working with Ray was slow, boring and Ray did not talk much beyond giving out guidance or asking for a needed wrench off his cart. Bob was more of a talker and would discuss topics off the news or family events, and there was never a pause in the action or dull task handed to you to work on.

I got along with both of them but work with Ray was dull. And more and more student workers would spend more time working with Bob. As a balance, I found myself working with Ray most of the time. Ray never told you more than you needed to know for a given task. As I watched Ray I often thought of the story of the rabbit and the turtle that decided to race. Ray was the definitive character that fit the “slow and steady wins the race.”

I also noticed that Bob’s team would often jump into a task only to find that one of the parts was assembled backwards, so that the next layer of assembly would not fit, and the prior effort had to be dismantled and corrected before the work could continue. Ray never had to do that.

Without saying anything other than giving you the basic instructions on how to proceed, Ray had somehow thought out all the possible errors that could be made and had adjusted his directions to actively avoid making mistakes. The more I worked with Ray the dullness of his action started showing me a level of efficiency that Bob never had. Ray taught by action. He did not tell you a joke or an odd observation he had driving into work, but he told you what you needed to know and what made his team do once and do it right.

So — why does any of this matter decades later?

Because the same principle that let me finish the gearbox project clean in week five while the rest of the class was still fighting the green lines is the same principle that separates real engineering from busywork. Plan the work first. Learn the tool when nobody else is using it. Rough in the geometry so you can edit it later. Verify everything old-school with pencil and paper before you trust the screen. Then execute.

The CAD stations were scarce. The software had no undo worth trusting. The assignment demanded real catalog parts and real calculations. Most students treated it like another homework race and lost. I treated it like the flight lab: think it through, load the right tools on the cart, and never have to backtrack.

That is exactly what Ray did every single morning. Bob’s energy looked productive until the rework started. Ray’s quiet notes on the legal pad looked slow until you realized his teams never tore anything apart twice.

The cost of rework is invisible in the moment. The time saved by forethought shows up only at the end. That is why the thinkers always finish first.

I spent thirty-two years in aviation R&D across two companies building things that could not afford to fail. I have broken things, investigated why they broke, and explained it to attorneys in courtrooms. Every single time the root cause traced back to the same choice: someone jumped in without thinking through the sequence.

The physics doesn’t lie. The catalog dimensions don’t lie. The torque loads don’t lie. Only the schedule pressure lies. And the schedule pressure always wins when you let it.

Ray never let it win. He sat with his coffee, made the notes, loaded the cart, and then moved once. I copied that exact habit on the CAD project and I have copied it on every major project since.

The green phosphor lines on that old Harris CAD are long gone. The software today will let you change one dimension and the whole assembly updates. You can simulate loads before you cut metal. You can 3D print a prototype overnight. None of that matters if you still jump in without thinking.

The hardware has changed. The mindset has not.

I tell you all this because the next time you sit down in front of a new tool — whether it is the latest parametric modeler or a completely different problem — remember the two mechanics at the flight lab. One looked fast. One looked slow. Only one never had to go backward.

Pick the slow one. Load your mental cart first. Then move.

The race is not won by the rabbit. It is won by the guy who already knows every possible mistake and has adjusted his directions to avoid making them.

How can I help you apply this same thinking to your next project? Drop a comment or reply — I read every one. Comments let me know what you want to hear more of or less of. Thank you

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