Parts List or BOM?

I started my career as a draftsman in Aerospace at Boeing Aircraft over 50 years ago. I quickly became a contract engineer and traveled all over the USA. They called us Jobshoppers, of which, I was a roadshopper working for many companies all over the USA.

"Have Drafting Machine, Will Travel"

My First 17 Years - "How did we do it without 3D CAD!"

It was always called it a PL or Parts List.

When I got into PC based 3D CAD and became a dealer I started hearing people calling the Parts List BOM or Bill of Materials. It always bothered me.

It took me awhile and a day of nothing to do to write an article on this subject.

CAD has four basic disciplines.

Architectural, Civil, Industrial/Mechanical and Entertainment

With AutoCad being the first PC based CAD system released it set a standard.

Sadly, AutoCAD was an “Architectural” electronic drafting package. To me it was very poorly designed, but then I was a mechanical draftsman. I had a couple of years’ experience on 3D Computervision CADDS 4 prior to being introduced to AutoCAD.  I was already creating engineering documentation from the 3D model. So to me, Autocad was just one small step above the drafting board.

While I was on contract with Boeing in Everett, WA in 1986, I was introduced to CADKEY. This was a PC based 3D CAD system. CADKEY could also create scratch drawings by just drawing on a defined plane or copy and paste the different 3D views of the 3D wireframe model in 3D space. It was a mechanical engineering package that was designed by mechanical designers for mechanical design. It worked like you did on the board. We would create parallel lines and AutoCAD was very point to point working with grids. But that was how architects design.

The 1990's - 3D CAD/CAM Moves to the PC!!

Okay there we have it.

We now had a true Architectural electronic drafting system and a true mechanical engineering 3D modeling system available of the PC.

It is quite shocking how there was only one PC based electronic drafting package available at the time. The major engineering companies bypassed the electronic drafting packages and went directly to 3D. So there was no demand from the large companies, they were already spending a fortune on the mainframe 3D CAD systems. Yes, Autocad did thrive in facilities in the big companies.


Autocad had “NO COPY PROTECTION” and was passed around like hotcakes. The industry was cheap in those days and no one was going to spend $4000.00 for what they could do for free on the drafting board. As an aside I did sell DataCAD which was sort of a 3D architectural package for $495.00. But Architects were really cheap and would not buy anything they could get for free. Productivity was not a concern.

I started selling CADKEY and it had a dongle and could not be copied. But I was lucky since it was the only PC based 3D CAD system that could speak to the high end 3D systems like Computervision and Catia 3/4. I not only sold CADKEY to Boeing but virtually every one of their suppliers. Word got out and we soon were selling to those that saw the advantage of 3D CAD.

I would walk into an Autocad house and fail to get them to buy even though the productivity of 3D was easily proven. Why? Autocad was free.

But things changed when Autodesk went out and started suing those that didn’t have valid licenses. They only had to sue a few, paying hundreds of thousands in penalties, and the rest fell into place. Even later when CADKEY took off its copy protection no company would have any non-licensed software on the premises. No one had to worry about a company copying software. But that was really not a problem with the individuals where 3D CAD was still freely passed around. That is how Solidworks became so popular, they didn’t put on strict licensing until 2007. Companies bought it off the recommendation of those that copied it and were familiar with it.

Okay, Okay…. Now with all of that knowledge under your belt.

Parts List or BOM?

Part List

Part list is a list of Parts. This was what the industrial/mechanical world used.





 Now why BOM?

AutoCAD was an Architectural program and they called it a BILL of MATERIALS.

This should be a DUH moment for all of you.

What are the materials to build a house? Yes… Wood, glass, nails, etc.


Due to the wide spread of AutoCAD into the mechanical/industrial industry many took on this term.

What is even funnier is that many of the mechanical 3D CAD companies took on the misnomer “BOM”. I just chuckled knowing they never thought it through. Why? That was the beginning of a "new" process now being run by those with very little applicable knowledge of the mechanical/industrial industry and took Autodesk's lead.

We are far passed the point where it would matter, so BOM's Away!

Another complete misnomer is the popular 3D CAD systems called their documentation modules “drawing modules”.

When CADKEY developed the separate documentation module they called it the layout mode. They realized that we were not creating drawings anymore. CADKEY was a system designed by mechanical designers for mechanical design.

The Death of the Drawing

But again those that did not understand the new process stayed with terms that really did not define what we were now doing. By still calling them drawings, it confused those that developed the new PLM nightmare.

PMI (Product Manufacturing Information) vs AID (Associated Information Document)

There you go something very simple completely overly explained. But what else do you do on a rainy morning in Seattle?

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WARNING: ZW3D is a professional 3D CAD engineering package and it is not recommended for those who are not engineering professionals or students with no prior 3D CAD experience. While we will help you get started we are not equipped at this price to teach you 3D CAD from scratch or engineering design. Don't let this low price fool you.

ZW3D now imports native NX, Solidworks, Creo and Catia 5 files with PMI


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Joe Brouwer