- I've had the opportunity to look at many history based models/assemblies and review their history trees and structure, coming from a variety of different CAD tools. While I see some models that are well structured with a good representation of design intent, most models are very poorly structured and really make no sense. They are clear examples of people just trying to get their job done as quickly as possible; get the models built, evaluate the design, make drawings and make parts. And a lot of these models are coming from companies that I would consider high tech and leaders in the industry.
- For further review I often load these models into my CAD tool of choice (Creo Elements Direct Modeling) and run a simple interference check. Since they are structured models I assume that errors will not exist, as many people believe that the structured model keeps them from making errors. Unfortunately, and all too often, I find many errors.
- I also find that recreating models is not too uncommon. This doesn't indicate that they are not getting value from the models, it just indicates that the cost of a well structured model may be much higher than most realize.
- They don't know of, or recognize, any alternative. Many people truly don't know that there is an alternative to history-based modeling and the structured model. Value is a relative thing, and if there is no recognition of alternatives, there is no recognition of opportunity.
- Many companies assume that strict modeling practices are being followed and as such assume they are getting value from it, but have really not done any work to validate this.
- The company may not be open to an alternative as migration costs are assumed higher than the potential return. Of course understanding potential return will require a clear understanding of alternative solutions.
- Individuals may not be open to an alternative as they have bettered their career based on their knowledge and skill with a particular tool. Learning a new one will set them back.
- User preference often gets higher priority than process improvement when it comes to tool selection. The cost of training can contribute to this. A lack of understanding in how the tool impacts process also contributes to this.
Before you start jumping to conclusions about the lack of value in an unstructured model, be careful not to assume that the unstructured model cannot be predictably controlled and/or represent design intent. Creo Elements Direct Modeling, for example, has a powerful 3D parametric solver built into it. Users can add control and design intent to geometry and assemblies at anytime in the process, independent of where or how the geometry was created. An IGES file can even be parametrically controlled and easily be made intelligent if desired. Assemblies and mechanisms can easily be brought to life for virtual prototyping. And don't confuse design intent with modeling intent. Here's an old example using imported models (although I should update this to Creo):
So the question is, are you really getting value from your investment in history-based CAD tool and the structured model? If so, what value? Do you understand the total investment, and does the value justify the investment? Are you sure you understand the alternatives?
There is certainly value that can come from the structured model, but many times this value comes at a great cost. I could go on about the various perceived values that people think they are getting from the structured model. Some are valid, some are not. Perhaps that is a topic for a different post.