How should I handle CAD file versions and revisions? A “Cosmo quiz” approach

Have you ever been confused about when to create a new version of your part or when to add a new revision? Is your company looking for a way to centralize and manage revision control? Read on.

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Managing CAD files is different from managing other types of data for a lot of reasons, and one reason why is the need for both version and revision control.  In fact, one of the main reasons companies adopt a PDM/PLM system is to make sure that versions and revisions are managed properly.  This post will provide a quick overview of why versions and revisions are important (and different from each other) then suggest some ways to manage them.

Version, revision, potato, potaato

First, let’s get our terminology straight.  Versions and revisions sound similar but mean different things.  First, versions - most CAD data management systems (like our own GrabCAD Workbench) enable you to “check in” files and create a new version each time.  A new version number indicates an update to the file.

Revisions are more significant  - a revision communicates that a milestone of some sort has occurred.  Revisions are typically designated by adding a suffix to the part number - Part 122038 Rev A, for example.  For people other than the designer, revisions are typically much more important than versions, since they communicate something about where the part is in the process.

Probably the most common use of revisions is to make it clear what version of a part should go to manufacturing.  A part is often marked as Revision A the first time it is ready to go to tooling. Rev B would be the next major milestone that Manufacturing needs to know about, generally a change that requires a tooling change.   A revision number appended to the part number makes that clear.  Because a revision reflects a decision by a human (i.e. “This is ready to be manufactured”), revisions are generally designated manually.

So how do companies handle versions and revisions?

It typically depends on how the team manages CAD files, which in turn tends to depend on the size of the team.  Here are some popular choices with their pros and cons (only with respect to version and revision control).

No revision control process

If your team has only one or two people, versions and revisions are typically a manual process at the discretion of the engineer.  The designer simply adds a version or revision number to the part number or file name.  They may store old versions in a separate folder.

Pros:

  • No cost for extra tools

  • No time spent managing process

Cons:

  • May not be possible to “roll back” to a previous version if an error occurs

  • No ability to control who can set revisions

  • No ability to publish a specific revision to partners

Manual revision control: File sharing service (Dropbox) or shared file server

Small teams try to keep things simple by using one file sharing tool for all their data  - photos, text files and CAD files.  Often they choose Dropbox for it’s ease and low cost or a shared file server because it’s already there.  Dropbox automatically creates file versions but doesn’t have any sort of revision control process and wasn’t created to handle CAD files, while a shared file server may be backed up (depending on IT support) but typically has no version control other than the snapshot created by the backup tool.

Pros:

  • Low cost compared to other options

  • Simple user interface

  • Already used by many consumers

Cons

  • No ability to designate revisions other than by changing file name

  • No ability to control who can set revisions

  • No ability to publish a specific revision to partners

Partially-automated revision control: Workbench or other cloud-based PDM tools

As organizations grow they find that they need more complex design and release processes as well as a consistent version and revisioning system.  These companies have access to tools that enable the version and revision control they need without the cost and process of more complex tools.  For example, GrabCAD Workbench tracks each version a user checks in, enables any user to restore a previous version, and allows a user to designate any version as a new revision.

Pros:

  • Low cost compared to other options

  • Archive and restore for all versions

  • Ability to designate specific version as a revision

  • Available on any device as well as to trusted users outside the company

  • Able to publish a specific revision to partners

Cons

  • No ability to create complex workflows for revision approvals

  • Limited integration with ERP and other systems

Fully automated revision control: Traditional PLM/PDM software

Once an organization has dozens of engineers making changes to a CAD model they may invest in a traditional Product Data Management (PDM) or Product Lifecycle Management (PLM) system.  These systems offer the greatest level of sophistication and control when it comes to versions and revisions.  PDM/PLM systems offer a fully controlled process that enables specific people to perform specific actions with respect to versions and revisions, as well as providing workflows to route files to certain people for approvals and integration with systems like ERP.

Pros:

  • Archive and restore for all versions

  • Ability to designate specific version as a revision

  • Integrates revision process with ERP and other systems

  • (Sometimes) Ability to control who can set revisions

  • (Sometimes) Ability to control process of revision approval and release

Cons

  • Very expensive compared to other options

  • Complicated to install and configure

  • Requires ongoing IT support and maintenance

  • Sometimes cumbersome for end users

  • Files generally only available to paid users

How do I choose?

There’s no one-size-fits-all solution for version and revision management.  The process that works for a Fortune 500 company would completely crush a small company, while the flexibility of loose revision control that works for a small company would create chaos at a large one.  The key to selecting a process (and a tool to implement it) is to start by understanding your needs.  Answer the questions below before you start - the more “yes’s” you answer, the more complex your needs are.

  • Do I have multiple people creating and updating CAD files?

  • Do I need robust version backup and restore?

  • Do I need a formal revision control system?

  • Do I frequently need to allow partners or suppliers to see specific versions or revisions?

  • Do I frequently need to control who can create versions or revisions?

  • Do I frequently need to support automatic workflows that route revisions for approval?

  • Do I need my revision process to integrate with ERP or other systems?

Scoring (Each “yes” = 1 point)

  • 0 points - Probably no need for a version or revision system

  • 1-2 points - Manual revision control sounds about right - check out Dropbox

  • 3-5 points - Partially automated revision control is probably a good fit - look at Workbench

  • 6-8 points - Fully automated revision control may be right for you- investigate PDM/PLM tools

Conclusion

There are more choices than ever for companies looking for robust CAD revision management.  Make sure that you take the time to understand your process and needs before committing to an approach, and make sure the tool you use supports your process.  Good luck!

Did we miss any key concerns or options?  Did your score surprise you?  Let us know in the comments.

  • http://www.dedicated.com.sa Mohamed Ali

    Thank you very much for this valuable article and covering this well.

    I really enjoyed reading.

  • Anonymous participant

    Few things that I would like to comment:

    Traditional PLM doesn’t need dozens of people before it’s a rational investment. There are many small companies that have few designers and yet they still use PLM.

    “Traditional PLM cons: complicated to install and configure, requires IT support and maintenance, cumbersome to end users, files generally available to paid users.”

    PLM configuration and installing is done by professionals and in most cases I believe the same company that you buy PLM for, does the configuring and installation for you. So for the user/company that part of PLM shouldn’t be a con as it doesn’t require their attention.

    IT support and maintenance. These are not requirements as maintenance/IT support is optional. False statement.

    Cumbersome to end users. Let’s keep in mind that PLM is highly configurable, you can almost get it to look like how customers wants and only those options and tools that customer needs. These things are specified before configuration starts and very often the people who decide these things are not end-users – designers. Also possible ERP system brings in whole lot of requirements from PLM which makes PLM seem like a clumsy software. Partially this is true, but have to note that if things were done right, this would be a minimal problem.

    I don’t know a PLM software from which you couldn’t export a file out. That’s how the file can be given to someone without a PLM licence. There are also viewer applications for PLM which lets you see the item info and 3D model in JT/CGM format, take dimensions of the 3D model etc. Example?

    I haven’t yet seen a PLM where you can’t define who can set revisions nor being able to control the process of revision approval and release. Example?

    About devices, you can see PLM info and 3D models even in your iPhone today if you want. Same as Workbench I guess. But why not mentioned in PLM pros as well?

    Of Workbench I would like to know what kind of support it has with ERP? It is said to be limited so Workbench can be connected to ERP?

    In Workbench can’t be created “complex” workflows. How you define a complex workflow, where the line goes? Ability to make own workflow even in small companies with their PDM system is an important requirement. How else you can control that the item info and drawing is at the required level, while also telling a buyer that there is a new revision of some drawing, while also telling product manager/project manager and head designer of an update and get their acceptance if required, while also telling manufacturing of an update to get them new drawings? These things are done by workflows automatically and are not complex, but rather basic stuff. Is that complex or not for Workbench?

    I would appreciate a lot if you Rob or someone else would answer to my questions and thoughts.

    • http://grabcad.com Rob Stevens

      Thanks for your comments, clearly this is a topic you care a lot about!

      You point out that many small companies do use PLM, and that the IT burden isn’t always high, and I completely agree with you that in some cases this is true. But at the same time, almost every PLM customer does in fact pay maintenance on the product, and also pays for IT maintenance – servers, databases and so on. In this blog post I’ve focused on the most common cases, and on what we heard from users. I’m sure there are examples to the contrary, but I don’t think that changes what most users experience.

      File export is a similar story – yes, PLM solutions allow export, but that’s not the same as making the files available to approved outside parties. File export makes the file available to a paid user so it can be sent to an outside user. Sending a CAD file to someone outside the firewall is a complicated task in and of itself. We have a number of customers who are happy PLM customers who use Workbench just for this ability – it’s easy to share CAD models securely outside the company.

      I agree that almost all PLM packages allow admins to set revisions and control approvals. This section was about PLM and PDM – I apologize that I originally left PDM out of the title of the section even though I mentioned it in the text, I’ve corrected that. Many of the simpler PDM have more limited controls around revisions which is why I said “Sometimes”.

      On workflows, as I note in the post Workbench doesn’t currently enable the use to create workflows, though this is something we will likely add in the future. There are other cloud-based PDM tools that do allow some workflow creation, I believe.

      Thanks for your careful review of the piece – let me know if you have other comments or questions.

      I’d also love to hear from others about their experiences with any of the solutions I discussed in the post.

  • Jan Salterod

    Well concidered article. Food for thought.

  • http://www.snriud.com lee

    The simens PLM system sucks,

  • http://www.mezatio.com/ Bertrand Mezatio

    thanks for the article ,i have learnt a lot about PDM and cloud PDM like workbench
    i have a PDM software called PTC Windchill and i found its very fustrating specialy when it come to revision management

    Regards
    Bertrand Mezatio
    TEL: 00 27 78 11 244 26
    FAX: 00 27 86 77 396 89
    E-MAIL: mezatio@mezatio.com
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    skype mezatiodesign