What are Revisions and Versions in PDM?

In SOLIDWORKS PDM (Product Data Management) there are two terms that can be confusing to new users or even administrators to understand and those are “Versions” and “Revisions”.


What are Versions?

A version is a simple number (always starting at 1) which will be unique to every document in your vault whether it’s a part, assembly, word document or another file type. This number will increment every time you check out the file, make a change and check it back in.  An example of this can be seen in the video below where a Word document is created and initially added to the vault, it’s version will automatically be set to 1 without the user having to do anything or set anything up prior.  We then check out the file, make a change to the file (saving as you go if they want) but as soon as the user checks the file back into the vault a new version will be created (in this case 2).  This does not delete the first version as can be seen at the end of the video where both versions are still accessible.



As the user continues to work on a file over several days, weeks or months many versions may be created as the user checks out and in the file.  Sometimes it may then be necessary for the user to revert to any earlier stage in the design.  This is when the user can use the “Get Version” command and select which version they would like to use going forward.  For example, in the image below the user may create version 1 through 4, but then after creating version 4 they may have preferred the design before the change to the roof so reverted back to version 3 by clicking on that version.  The user can then make new changes to the model and check this back in.  At which point it will not overwrite version 4 but instead create a new version (5).  Especially when reverting to earlier design it is usually very handy to make sure that when the file is checked in that a short comment is inserted so that you can keep track of changes between each version.



How does this affect my File Sizes and Storage Capacity?

As you add more versions, many users think this will increase the file size respectively which isn’t quite the case.  If your file is initially 10Mb and you have 10 versions, this will not take up 100Mb of storage capacity in your vault.  The PDM System is intelligent and will keep track of the changes between each version so the file size for the 10 files may only be around 15Mb in total but this also depends on how big the changes you make between each are.


What are Revisions?

Revisions are another way to keep track of changes to a file but rather than being controlled via physical changes to the file (by check out and in), the Revision is controlled through the workflow of the file. This is useful as you most likely want a way to keep track of which ‘version’ you are sending to manufacture.

A good way to describe this is you may have a lot of versions and when you hit say version 4, you send that to manufacturing which would now be referred to as Revision A (and version 4) which you make and sell.  You then want a newer model so you take the model you sold previously, make many new changes and end up reaching version 13 which you send to manufacturing and this would be Revision B.

The revision is controlled via a “Revision Scheme” and could be a number (1, 2, 3…), a letter (A, B, C…), alphanumeric (A1, A2, A3…) or a custom value through a custom-made serial number generator which could require someone to write the code for a serial number.

When it comes to setting up a Revision Scheme, I won’t go into too much detail but if we look at the example Workflow below we can take the “Released” state as the final stage so the first time the file is in the Released state it would be Revision A (using Alpha scheme for example).  If the file then requires a new version, it would go through the “New Release” transition, go back through the workflow as Revision B and eventually hit the “Released” State again.  This process would then become cyclical.

Another way of thinking of both version and revisions is that versions keep track of small changes to the file/s, but revisions keep track of overall large changes (multiple versions).


Can I have more than one Revision Scheme?

With PDM Standard you are limited to a maximum of two revision schemes which can be of different Schemes.  With PDM Professional you have no restrictions on the number of Revision Schemes and these can also be setup for a serial number generator.



Craig Girvan is an Applications Engineer at TMS CADCentre, a SOLIDWORKS Value Added Reseller in Scotland.

You can read more from Craig on the TMS CADCentre blog

TMS CADCentre is a SOLIDWORKS Reseller based in Scotland providing CAD Design Software, analysis software & product data management software. Founded in 1981, TMS CADCentre is the only UK SOLIDWORKS Reseller based and funded within Scotland and have been providing SOLIDWORKS software, training and support since 1996 when the product was first launched in the UK.