In recent years, much has been made about the relevance of direct modeling on simulation activities. Somewhere along the way, many have forgotten how parametric modeling is just as important. In this post, we’ll take a look at why simulation activities need to be enabled by both.
Direct Modeling for Preparation and Iteration
A troublesome activity in the simulation process, at least to this point, has been the abstraction and simplification of detailed design models. Such modifications remove or replace geometric details that might lead to challenges in creating a mesh, and other aspects of the model not relevant to the simulation at hand.
The reason this has been so difficult lies in the fundamental nature of parametric modeling. An interdependent history of features can be a fragile thing. The removal of one piece of geometry might cause a cascade of feature failures throughout the rest of the model. Analysts rarely have the skills, knowledge and time to deal with such issues.
That’s where direct modeling is a great boon. Many CAD applications with such capabilities ignore the interdependencies between features. They allow the user to manipulate the geometry directly with simple and easier tools, avoiding failures that plague parametric modeling methods.
Furthermore, analysts often need to make suggestions about the design in the form of geometric modifications. It might be thickening a rib here or increasing a radius there. Again, direct modeling methods allow analysts to perform those actions without the fear of cascading failures.
Parametric Modeling for Design Exploration
While direct modeling is useful in the preparation of simulation models, parametric modeling serves an important purpose in the simulation process. In addition to conducting one-off simulations to predict how designs will perform, analysts and engineers need to understand the full design space. Gaining insight into how design objectives — like weight, stiffness and cost — are affected by specific design traits and characteristics — like shape, size and material — is priceless.
Therein lies one application of parametric modeling. It enables engineers and designers to embed their design intent into a 3D model. Furthermore, it powers design automation, allowing someone to make a manual or automated modifications and transform the design into something quite different. These capabilities enable the changes to the 3D model necessary to run sensitivity, optimization and design exploration studies, which can dramatically improve the performance or cost of a product or component.
However, it’s not just as easy as taking a detailed design built using parametric modeling and dumping it on the analyst. In fact, those models frequently aren’t modeling robustly enough for the wide range of modifications required. Instead, some organizations are building parametric models of designs specifically for the purpose of simulation. They are carefully crafting them both for simulation and abstraction as well as incredible robustness and flexibility. This works well in the concept design stage, before detailed designs even exist.
The impact can be tremendously powerful. Going into detailed design, designers and engineers have a roughed out design that has proven to perform at a high level.
Recap and Questions
All in all, I find the trajectory of these technologies quite surprising. My main point here, of course, is that both direct and parametric modeling are important enablers to simulation. However, who thought that direct modeling would be critical to enabling analysis in detailed design? And who foresaw that parametric modeling would be imperative to design exploration in concept design? In all honesty, I can’t raise my hand.
Those are my thoughts folks. What are yours? Do you agree that parametric modeling is moving upstream to enable concept simulation? Do you think direct modeling is a critical enabler to detailed design analysis? Sound off. Let me know what you think.
Take care. Talk soon. Thanks for reading.
This blog post has been licensed for hosting by PTC. The concepts, ideas and positions of this post have been developed independently by Industry Analyst Chad Jackson of Lifecycle Insights.
Original post by By Chad Jackson | Published: May 12, 2014