Have you ever had to bodyblock a co-worker to get access to an important document or file?

Fortunately, I’ve never been driven to such extremes. But having devoted most of my professional life to improving CAD systems, there are some engineering stories that remain forever etched in my brain.

A customer recently told me that he went out into the parking lot and stood in front of a co-worker’s car – stubbornly planting his body to block the car from leaving. The driver had some CAD files checked out of their Product Data Management (PDM) system and was going on vacation. The bodyblocker was afraid he would not be able to work on specific models for days – and demanded that those files be checked back in before his co-worker started sipping margaritas.

Those fears of being blocked from work were justified.

Many companies use PDM systems to manage changes to their countless files for parts and assemblies. To prevent different team members from each taking a copy of the file and making conflicting versions, a PDM system works like a bank vault with strict rules. Only one person can check out (and work on) a file at a time. 

If you are waiting for access, the PDM vault will tell you who has “your” file, so you can track him or her down and check its status. Sometimes the offending co-worker is already done with the file but forgot to return it. People get busy and distractions happen. Although PDM systems were designed with the best of intentions, they create a whole new set of problems. By locking co-workers out, the system inherently forces you to work serially instead of collaborating together.

CAD users tell me that they can never do just the right amount of checkout. They either checkout too often and slow everyone down, or checkout too seldom and overwrite each others’ work.


Serializing work is incredibly inefficient. Imagine a book club that has to share one copy of the same book. In such a book club, only one member could read the story at a time – instead of everyone enjoying it concurrently. This book conversation would take a year to get started.

So why do companies use PDM? The most common reasons are:

  1. Version Control - CAD users can always know the latest version of a file and keep track of older versions in one central place.
  2. Avoiding Design Conflicts - The system prevents the aggravation of people overwriting each other’s work.

Although both of these goals are achieved by PDM, they come at great cost (not to mention the exorbitant cost of the systems themselves, which can start at $20,000 to $30,000 and up). Upfront investments aside, many CAD users regard PDM as a cumbersome bureaucratic system that creates roadblocks to creativity and productivity.

PDM systems are also enormous copy machines. Every time you check out a file, you’ve made a copy. If you’re working with someone at a different company, and you attach the file to your email, now they also have a copy. So it’s not just an access control problem, but a version control problem, too.

Once those copies are out of the vault, the uncertainty keeps building: What is the latest version? Does everyone on the team have the latest version? How can I be sure I am working with up-to-date data?


Even when engineers and designers love their CAD system, the odds are high that they’re grumbling about their PDM. I frequently hear the word “hate” come up in conversations about PDM, regardless of vendor or brand. But as frustrating as file checkout and file locking can be, it’s not PDM’s fault that you’re angry.

Traditional CAD systems were never designed for distributed teams. We know because we built traditional CAD. It used to be that a product was designed and manufactured under the same roof. Today, the design and manufacturing chain is often distributed across the country or even across the world.

And here is where we collectively hit a brick wall. You know what your company needs to do to use PDM at your locations in LA, Phoenix and Boston? You have to create duplicate servers at each location and your IT department needs to sync them over leased lines. PDM systems were designed to be run on LANs. They were never meant to be put on the public Internet.

It’s unfathomable: To keep track of your files, you need to buy a private data connection. That’s like buying a car and then having to pave your own road!

The only way traditional CAD and PDM can work over network connections is by copying large sets of files back and forth, which is extremely slow under the best of circumstances. They need lots of bandwidth and get bogged down during the long file-copying process.  Thus the need for dedicated network lines to try to make it even barely usable.

In the LA-Phoenix-Boston example, you need to have complete copies of everything in the vault in all three places. Leased lines allow you to sync faster so there’s less of a chance that you’re overwriting each other’s changes. But even with all those precautions, things can still go wrong. If you check something out in Phoenix, and I go to check it out in Boston, I may not find out in time that you already checked it out. Or you could check something in, and I could then check it out, but your most recent changes might not have been synched yet.


So everyone in the industry is saying, “Well, we’ll do PDM in the cloud.” Well, checking out (and downloading) files from the cloud is still checking out and copying files – and it’s still a problem. At Onshape, we’ve used the cloud to make a system where people can work together without ever having to worry about checkout.

Onshape is a full-cloud CAD system, with no files and no copies, designed for optimal performance over the Internet. Onshape is the first and only professional 3D CAD system where the CAD system and the CAD data live in one place in the cloud. Neither the CAD system or the CAD data are ever copied anywhere.

There’s no problem finding the latest version because there is only one place to look. 

Remember those problems that inspired the creation of PDM? By changing the fundamental architecture of CAD, we’ve made them history:

  1. Version Control - With Onshape, CAD users will always be working on the latest version. No more copies. No more potential confusion and misunderstandings. There is only one version of the truth.
  2. Avoiding Design Conflicts - Tailored for the collaboration needs of modern distributed CAD teams, Onshape enables multiple users to modify designs at the same time or whenever they want – no matter where they are or which computers, tablets or phones they are using. 

In regards to the security issue created by the PDM “copying machine,” Onshape gives you full access control for the full life of your data. There is one designated owner for every document and that owner can assign (or revoke) different permission levels. You’re never sending a file or a copy out into the world.

Point blank: There’s no longer a need for a complex (and incomplete) solution once your original problems have disappeared. PDM systems were a valiant attempt to make traditional CAD work for teams. Onshape is a new generation CAD system that lets teams work together without PDM systems, without checkout, and without copies.

And we promise that you’ll never have to bodyblock your co-workers in the parking lot.