One of the key roles of Product Data Management software is to manage and organize the complex interdependencies that 3D CAD creates between each type of file, some of which may not be so obvious. Before diving into the nitty-gritty of data management, it’s worthwhile taking a moment to explore how these interdependencies are created and the problems they sometimes cause.
At a basic level, each CAD file contains either a part, an assembly or a drawing.
- A Part file is the basic unit that all other aspects of a parametric 3D CAD system rely upon. It contains the feature-by-feature definition of a model of a component that may later be used in an assembly or a drawing or some other downstream deliverable like simulation, CAM or rendering.
- An Assembly file relies on a part file to provide the necessary geometry so that it can position it relative to other parts in the assembly.
- A Drawing file relies on a part file to provide the necessary geometry to create drawing views and accurate measurements for dimensions and other annotations.
Neither an assembly file nor a drawing file contain the geometry required to accurately depict correct part geometry. Some systems may cache this data as a snapshot in time in the assembly or drawing file, mainly to enable viewing software to display the geometry without having all the files present. But cached data may be out of date, so it’s a risk to rely on this information. Think of a drawing with cached data like a print – it could potentially be out-of-date the moment it is created, and it’s almost impossible to tell if it is obsolete or not without further investigation.
Therefore, in order to depict the latest design accurately, an assembly or a drawing cannot truly exist without access to the required up-to-date part files. If a part file goes missing, becomes corrupt, is changed without permission or is just generally interfered with, the assembly and drawing could potentially be wrong and cause untold damage to a project.
Likewise, viewing a drawing containing cached data could be extremely out-of-date. When considering the scrap, operator time and rework involved, incorrectly manufactured parts cost companies millions each year. Unauthorized modifications to just one part in a project could have a domino effect on others, multiplying the incorrect part count and thus the overall lost time and money.
Carefully crafted parametric models can propagate changes quickly and effectively to all downstream deliverables such as assemblies and drawings. Unfortunately, very few parametric models are as resilient to design changes as they should be. Engineers don’t have the luxury of time to plan ahead and define robust references between features in a part and parts in an assembly. Project deadlines are always looming and design changes come thick and fast. The results, through no fault of their own, are models which fall apart at the slightest change.
This flakiness causes models to fail and references to be lost. Faces that were used in an assembly go missing and edges that were dimensioned in a drawing move without warning. A simple design change can have a severe domino effect.
Managing these interdependencies can only effectively be achieved using data management software. Vendor-supplied PDM software understands the data structures inside each file and knows which files are dependent upon others.
The Downside of File-Based PDM Systems
According to “The State of Product Development & Hardware Design 2019,” an independent industry survey of 850 product design and manufacturing professionals, more than 8 out of 10 respondents acknowledge that they have a version control problem. There is confusion over which version of a design is really the latest version, a scenario that leads to costly manufacturing errors.
For the most part, file-based PDM systems have been successful in preventing these kinds of mistakes, but they are not without their pitfalls. PDM requires engineers to checkout and check in design files back in “the vault,” meaning that none of their colleagues can work on the file until the first engineer is done. This kind of serial workflow inevitably slows down the product development process, particularly when there are nightmare stories of a co-worker going on vacation after forgetting to check a file back into the system.
So not surprisingly, the industry survey revealed that more than 7 out of 10 product development professionals using file-based PDM/PLM systems “wish there were a better way” to prevent version control problems.
Is there a better way? You bet.
The Benefits of Cloud-Based Product Data Management
As I explored in my recent blog, “Think You Can’t Afford PDM? Think Again,” it is estimated that only 40% of product development companies use any sort of PDM and/or PLM solution at all. Their reasons for avoidance vary from the traditionally high price tag to the extraordinary IT resources needed to install and maintain file-based systems. It’s a head-in-the-sand approach which ignores the much higher costs of manufacturing the wrong parts and possibly creating defective or inferior products.
Onshape believes that product data management shouldn’t be an “extra” system added on top of your design tools. Version control is built into the core of our cloud-based platform. Consider these differentiators:
- Onshape’s unique cloud database architecture completely eliminates files, removing one of the most frustrating issues associated with CAD and PDM. No work is ever lost, overwritten or modified without permission. Entire teams can edit the same design at the same time with real-time updates – there is no need to check-in, check-out or lock, removing all bottlenecks from the design process. Every design change is captured and recorded with unlimited undo/redo and a complete audit trail of who made what changes and when.
- Onshape also ensures that all the software tools you need are available at your fingertips as and when you need them, without having to involve your IT department. Simply sign-in to your secure cloud workspace from any available device for immediate access to all your design data, plus all the data that has been shared with you by co-workers, suppliers and customers. Every project stakeholder can get their hands on the latest design information whenever and wherever they need it.
Interested in learning more about how Onshape’s cloud product development platform stacks up against a file-based PDM system? Our latest eBook,“The Engineering Leader’s Guide to Data Management & PDM,” will help you evaluate your current processes and help you compare and contrast alternative solutions. Download your free copy here.