Will Model-Based Definition Be the End of 2D Drawings?

Will Model-Based Definition Be the End of 2D Drawings?

By: Polly Britton
Project Engineer, Product Design

26th July 2017

Home » CAD

Despite advancements in computer-aided design over recent decades, 2D technical drawings remain as the industry standard deliverable. This means that after designing a part for a customer or manufacturer in 3D, they will expect you to prepare drawings like these:

Click images to zoom

This way of representing a 3D object on a 2D page through using a number of different viewing angles is called “Multi-view orthographic projection; it has been the standard for engineering design across most of the world for many decades now. The 3D model is just a tool to help create the drawing views and dimensions, which are what truly define the part.

But now there is another way…

A rotatable 3D model with dimensions, tolerances, and annotations all included. It’s called “Model-based definition (MBD)” and there are some who think it is the future of engineering design. A simpler version can be seen below, just click the play button to enable the 3D ability.

As computers become more powerful, more people than ever before can open a 3D model file, like this one pictured, on their PC, tablet, or even smartphone. People can also intuitively figure out how to navigate around the model to find and extract the information they want from it.

Is it better?

To overcome the 2D drawing’s legacy of over 200 years, any new system trying to take its place would have to be far superior to encourage engineers to make such a major change to how they work. So what are the advantages?

Seeing is understanding

Trying to imagine a solid object using information from “flat” 2D views sometimes results in errors, and unnecessary mental gymnastics that are done away with when using MBD. However, standard 2D drawings already have a solution to this, which is to include a 3D orientation view.

A view like this one on the right, or even a few of them, can go a long way to helping the reader understand your drawing. 3D orientation views can be easily generated from Computer Aided Design (CAD) models.

Dimensions

MBD does make it easier to find information about a particular feature all in one place. Just zoom-in and see every dimension you need to fully understand the feature. This replaces the need of having to inspect multiple 2D views to find the various dimensions for the width, height, and depth, which might be far apart on the page. These dimensions can even include geometric tolerances (the subject of my last blog).

File types

There is no universal or standard file type for MDB yet. Different CAD packages have different file type outputs that require a specific program to be installed on your device to open. Some PDF readers can display 3D PDFs, which allow you to examine 3D models and their annotations in a slightly cruder, less controlled way.

With 2D drawings, all you need to view them is paper, which can then be copied and carried into workshops and meeting rooms, and easily annotated by hand if necessary. And when the project is finished the designs can be physically archived in your company’s filing system of choice. These days, it is common to save drawings as PDFs, which can be opened on any device, and archived electronically. And that’s the way we like it, for now at least.

Conclusion

So, as the title of this blog asks, will model-based definition be the end of 2D drawings? I don’t think it will happen soon. The small conveniences allowed by MBD are not enough to encourage engineers to convert to a new format, especially one with its own set of difficult quirks. MBD may well become more popular in the future, but for now, I believe old-fashioned 2D drawings will still play a fundamental role in engineering and my career.

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Despite advancements in computer-aided design over recent decades, 2D technical drawings remain as the industry standard deliverable. This means that after designing a part for a customer or manufacturer in 3D, they will expect you to prepare drawings like these:

Click images to zoom

This way of representing a 3D object on a 2D page through using a number of different viewing angles is called “Multi-view orthographic projection; it has been the standard for engineering design across most of the world for many decades now. The 3D model is just a tool to help create the drawing views and dimensions, which are what truly define the part.

But now there is another way…

A rotatable 3D model with dimensions, tolerances, and annotations all included. It’s called “Model-based definition (MBD)” and there are some who think it is the future of engineering design. A simpler version can be seen below, just click the play button to enable the 3D ability.

As computers become more powerful, more people than ever before can open a 3D model file, like this one pictured, on their PC, tablet, or even smartphone. People can also intuitively figure out how to navigate around the model to find and extract the information they want from it.

Is it better?

To overcome the 2D drawing’s legacy of over 200 years, any new system trying to take its place would have to be far superior to encourage engineers to make such a major change to how they work. So what are the advantages?

Seeing is understanding

Trying to imagine a solid object using information from “flat” 2D views sometimes results in errors, and unnecessary mental gymnastics that are done away with when using MBD. However, standard 2D drawings already have a solution to this, which is to include a 3D orientation view.

A view like this one on the right, or even a few of them, can go a long way to helping the reader understand your drawing. 3D orientation views can be easily generated from Computer Aided Design (CAD) models.

Dimensions

MBD does make it easier to find information about a particular feature all in one place. Just zoom-in and see every dimension you need to fully understand the feature. This replaces the need of having to inspect multiple 2D views to find the various dimensions for the width, height, and depth, which might be far apart on the page. These dimensions can even include geometric tolerances (the subject of my last blog).

File types

There is no universal or standard file type for MDB yet. Different CAD packages have different file type outputs that require a specific program to be installed on your device to open. Some PDF readers can display 3D PDFs, which allow you to examine 3D models and their annotations in a slightly cruder, less controlled way.

With 2D drawings, all you need to view them is paper, which can then be copied and carried into workshops and meeting rooms, and easily annotated by hand if necessary. And when the project is finished the designs can be physically archived in your company’s filing system of choice. These days, it is common to save drawings as PDFs, which can be opened on any device, and archived electronically. And that’s the way we like it, for now at least.

Conclusion

So, as the title of this blog asks, will model-based definition be the end of 2D drawings? I don’t think it will happen soon. The small conveniences allowed by MBD are not enough to encourage engineers to convert to a new format, especially one with its own set of difficult quirks. MBD may well become more popular in the future, but for now, I believe old-fashioned 2D drawings will still play a fundamental role in engineering and my career.

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An insight from a PCB Design Apprentice

An insight from a PCB Design Apprentice

Elliot Langran - PCB Design Apprentice

By: Elliot Langran
PCB Design Apprentice

26th April 2017

Home » CAD

Hello, I’m Elliot Langran and I am the PCB Design Apprentice here at Plextek, I started in September and here is an insight from my perspective of life as an apprentice.

I generally get into the office between 9 – 9:30 am, being a young person, I’m extremely grateful for our flexible working hours. It does mean staying later than most, but at least I can claim I’m running the show later in the day, if only for an hour or so. I start the day catching up with the team and of course grabbing a cup of tea to get me kick-started. The first thing I do is get everything set up including the Computer Aided Design (CAD) tools, and PADS layout, the Printed Circuit Board (PCB) design software. I’d be lost without these.

PCBDesign4-500Being a PCB Design Apprentice is really varied and my average day can be spent doing a range of different things, generally speaking, no two tasks are the same. When I started my apprenticeship, I luckily wasn’t expected to know how to design a 12 layered PCB.

However, excitingly, I am now on my way to gaining the relevant skills. This makes a 12 layered PCB less of a daunting idea as each day I am developing and learning.

One thing that has become apparent to me is that each PCB designer has their own style as each designer lays out their board differently (it’s nice to know that I will develop a PCB signature). Understanding and being exposed to a range of layout options and developing multiple skill sets is vital for me in crafting my own style further.

PCBDesign1-500What I enjoy about the job is the creativity and it’s one of the first principles that I was taught here: never copy anybody else’s design, and develop your own style and way of working instead. This is helped by the constant support and guidance from my mentors. They are always advising and guiding me on where improvements can be made and are key people in my development as an apprentice.

I’ve been learning a lot by looking at the other designers’ work from time to time and noting their style of approaching layouts for example. They can work on as many as 16 layers of PCB board, it’s quite crazy actually. I am currently able to work up to 4 layers and the tracking gets more complicated each time you go up a layer pair. This is made even more challenging if you have less board space to work on.

I also spend some of my time working on mechanical drawings, which really brings extended variety to my work day! These drawings are needed often during projects, especially for cable assemblies.

PCBSo there is a lot of variety in my job; PCB design, schematics and sometimes mechanical drawings, not to mention college work as well. My line manager and mentor are always really supportive of my college work and both think it is important to get done whenever there is a quiet moment. This has been vital to my success in my apprenticeship studies and is greatly appreciated.

The organisation is always showing great enthusiasm towards the apprenticeship scheme and my personal development. This has been recognised by my college, Cambridge Regional College, at this year’s Apprenticeship Awards as we won “Engineering Employer of the Year Award”. I look forward to developing here during my apprenticeship and the adventures and interesting projects that await me.

Hello, I’m Elliot Langran and I am the PCB Design Apprentice here at Plextek, I started in September and here is an insight from my perspective of life as an apprentice.

I generally get into the office between 9 – 9:30 am, being a young person, I’m extremely grateful for our flexible working hours. It does mean staying later than most, but at least I can claim I’m running the show later in the day, if only for an hour or so. I start the day catching up with the team and of course grabbing a cup of tea to get me kick-started. I first get everything set up including the Computer Aided Design (CAD) tools, and PADS layout, the Printed Circuit Board (PCB) design software. I’d be lost without these.

PCBDesign4-500Being a PCB Design Apprentice is really varied and my average day can be spent doing a range of different things, generally speaking, no two tasks are the same. When I started my apprenticeship, I luckily wasn’t expected to know how to design a 12 layered PCB.

However, excitingly, I am now on my way to gaining the relevant skills. This makes a 12 layered PCB less of a daunting idea as each day I am developing and learning.

One thing that has become apparent to me is that each PCB designer has their own style as each designer lays out their board differently (it’s nice to know that I will develop a PCB signature). Understanding and being exposed to a range of layout options and developing multiple skill sets is vital for me in crafting my own style further.

PCBDesign1-500What I enjoy about the job is the creativity and it’s one of the first principles that I was taught here: never copy anybody else’s design, and develop your own style and way of working instead. This is helped by the constant support and guidance from my mentors. They are always advising and guiding me on where improvements can be made and are key people in my development as an apprentice.

I’ve been learning a lot by looking at the other designers’ work from time to time and noting their style of approaching layouts for example. They can work on as many as 16 layers of PCB board, it’s quite crazy actually. I am currently able to work up to 4 layers and the tracking gets more complicated each time you go up a layer pair. This is made even more challenging if you have less board space to work on.

I also spend some of my time working on mechanical drawings, which really brings extended variety to my work day! These drawings are needed often during projects, especially for cable assemblies.

PCBSo there is a lot of variety in my job; PCB design, schematics and sometimes mechanical drawings, not to mention college work as well. My line manager and mentor are always really supportive of my college work and both think it is important to get done whenever there is a quiet moment. This has been vital to my success in my apprenticeship studies and is greatly appreciated.

The organisation is always showing great enthusiasm towards the apprenticeship scheme and my personal development. This has been recognised by my college, Cambridge Regional College, at this year’s Apprenticeship Awards as we won “Engineering Employer of the Year Award”. I look forward to developing here during my apprenticeship and the adventures and interesting projects that await me.

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Further Reading