By Uli Mahle
Uli Mahle is VP of Marketing & Product Development CoCreate Software
With some 3D CAD, software product development is something like installing masonry. Building a wall requires laying one layer of bricks over the other. It may not be until most of the bricks are laid that you realize there is a problem. Then to fix it, you have to remove bricks; or, if the problem’s at the bottom, you might have to tear down the whole wall and start over.
3D CAD software based on a history tree lends itself to this masonry analogy. Layers of complexity are added step by step. A finished model is not simply the visible geometry, but the summation of all 3D modeling operations. To make an alternative late in the process, you may have to step back through the sequence of modeling operations.
Changes in masonry are hard because of locking interdependencies; some changes in 3D CAD software can be difficult because of the history tree. Developing a new product, however, is by nature iterative. Even the most masterful engineer cannot foresee all the variables of a complex object.
“As a consultancy, we know our clients are going to make changes and we work on projects that change all the time,” says Tim Nugent, Founder and Partner, Pulse Global, a consultant. “The last thing that we want is software that is going to slow down our ability to adapt.”
Dynamic Modeling or History-Based CAD?
In the world of product development, there are two approaches to 3D product development – a dynamic modeling (history-free) approach and a history-based approach.
History-Based Modeling: A history-based 3D CAD system creates geometry through a series of 2D sketches and 3D modeling commands that build the history tree. Engineers carefully construct the model to allow for potential future modifications. Constraints on the profiles and relationships try to anticipate areas where potential modifications may occur.
Modifications in a history-based approach require a sound understanding of how the model was created. This includes the original profiles, constraints, and relationships and the order in which they were created. To make a change, you also need to know how the part is related to other parts in the assembly. Once a change is initiated, the model must often be “regenerated.”
“One of my customers constantly has a lot of changes and I was always running into issues because of the history tree,” said Larry Potts, President, Two Rivers Studio, a company that specializes in design of injection-molded products for the medical industry. “Everything was interconnected on the 3D models and I couldn’t easily undo things to make changes. Too often, I would re-model parts rather than spend the time to reorder the history tree to make the changes.”
Dynamic Modeling:After changing to a dynamic modeling 3D CAD system, however, Potts no longer reports this problem. With this approach, geometry is created similar to other systems using profiles and common machining commands. The difference is that modeling steps are freely executed and not stored and maintained in a history tree. Therefore, designers are not required to apply constraints on the profiles and resulting 3D models.
Starting Up: The trend towards dynamic modeling attracts companies of all sizes – from small to large. Small companies new to 3D design often find the dynamic modeling approach natural to them; it’s easy to learn without the nesting of locking interdependencies.
Dan Corbosiero, Engineering Manager at DynoTune, a manufacturer of specialty motorcycle parts, initially found an instructional class for a history-based 3D CAD system so daunting as to hold back the company’s move from 2D to 3D. But when he tried a dynamic modeling 3D CAD system, he could make manufacturable parts for his business almost immediately. “I downloaded the personal edition and within 45 minutes I was able to create a molded 3D part,” he says. “It is so intuitive. I was able to use the software just by following the prompts.”
Teams: A dynamic modeling approach has also won allegiances from companies that seek the same team productivity from their product-development software that they enjoy from their office-productivity tools. This approach allows 3D designs to move among a team of engineers like Microsoft Office Word documents pass between team members.
Because only the engineer knows the interdependencies among a design’s features in a history-based 3D CAD system, only that engineer can comfortably make changes. Bottlenecks are frequent and at times difficult to overcome. A dynamic modeling approach, by contrast, allows changes by an engineer without knowledge of how the original model was constructed. This allows a design team to reuse data rather than have to recreate designs from scratch.
“Our team is made up of people having different specialties. Sometimes a project can stay with one person, and other times it requires more,” add Nugent. “The nice thing about a history-free 3D CAD system is that anyone can work on a model…”
Innovation: Beyond allowing projects more flexibility horizontally – among many engineers – a dynamic modeling approach gives innovative companies the ability to go forwards and backwards in product development. “Within a history-based environment, designs become too precious to change because of the time invested in coming to a particular solution,” explains Geoff Gosling, Director of Design at DIRTT Environmental Solutions, a company that designs and manufacturers innovative modular interiors. (DIRTT stands for ‘Doing It Right This Time’). “Dynamic modeling is different. You can start exploring without a sense of making a mistake that will cause you to lose your previous investment in a model.”
Repurposing: Even companies that have configured design data-management software often struggle to reuse existing designs. Not because they have a hard time finding them, but because most designers struggle to understand how the part was originally created. Even designers who built the original history tree may be at a loss when viewing the history of a 3D model long after originally creating it.
A dynamic modeling approach eliminates history and breaks the interdependencies on 2D profiles and 3D modeling steps in order to drive 3D changes. As a result, companies can transform existing 3D geometry from previous projects to satisfy new market requirements. This capability can produce dramatic time saving for custom design and build-to-order products, or for companies having strong demands to leverage existing design work in new products.
The Dynamic Future: The flexibility of this approach allows a more responsive process —one that is more amenable to changes, and allows the entire process to move forward faster. Companies save time and costs by repurposing existing designs for new projects, building and testing multiple iterations, and making late-cycle changes in response to changing customer requirements or market opportunities.
Dynamic modeling also fosters a more collaborative environment with more flexible schedules: engineers can hand models back and forth to each other – whatever is necessary to keep a project moving forward, on schedule and on budget.
When viewed from the wider perspective of the overall design process, dynamic modeling may offer advantages that lead to higher quality products through a method that is more flexible and productive. In today’s race to create unique products, companies need to be able to make rapid, last minute changes to product designs.
Agilent uses 3D CAD to speed three parallel designs
Agilent’s LC/MS and GC/MS systems (mass spectrometry solutions) are cutting-edge instruments used to solve everyday mysteries. Unknowns can be identified by providing information about a compound based on the characteristic ions created in the mass spectrometer and the retention time in the chromatograph.
These systems are routinely used in such applications as environmental testing, pharmaceutical analysis, food testing and forensic applications. Scientists depend on these systems to answer the questions of “What is this?” and “How much is there?” You’ll find Agilent’s products on CBS’ hit show ‘CSI: Crime Scene Investigation.’
Within their high-tech industry, speed and cross-leverage is critical to setting a leader’s pace. For example, Agilent recently simultaneously launched three new instruments: the 6100 Series Quadrupole, the 6410 Triple Quadrupole, and the 6510 Quadrupole Time-of-Flight (shown).
“Time-to-market pressure was the main driver behind these three products. There was an opportunity to move against competitors on this equipment, and we had to get these out into the market fast,” said James Bertsch, 6510 mechanical project lead. To gain efficiencies within their manufacturing process, Agilent tasked the three design teams to work together in cross-platform development to reuse shared components.
“We shared as much as we could in order to push production volumes up, which drove manufacturing costs down. Sharing designs across products also minimized engineering times because the teams could reuse each other’s work,” said Ed Cirimele, 6410 mechanical project lead.
Agilent used the CoCreate OneSpace suite to support the process, enabling them to harness the power of teams and develop products with speed, flexibility and responsiveness to change.
OneSpace Model Manager is at the heart of Agilent’s global product-development process, serving as the central location for engineering teams to store and access designs.
“OneSpace Model Manager allowed us to design the three platforms in parallel. The majority of designs were used in more than one project, but in different combinations.
(The software) kept track of all the different configurations and made it easy to find and reuse designs,” said Bertsch.
“Without Model Manager every engineer would have their own filing system and way of storing parts. You would have to constantly work with three, four, or five different engineers’ way of storing models,” Bertsch added.
Speed, Flexibility: CoCreate’s dynamic modeling approach eliminates history and breaks the dependencies on profiles and modeling steps in order to drive 3D changes. It is an environment where 3D geometry is always king and design creation and modification is fast, easy, and flexible.
This frees Agilent to reassign project responsibility based on development priorities and resource availability because anyone can carry a 3D design forward. “Several times we had team members (out)…. Another team member accessed the latest version of the design and made the needed changes. Revision management and change notes made it easy to roll to an earlier version if the original engineer wanted to solve the problem differently,” said Bertsch.
Agilent has streamlined its product-lifecycle management (PLM) process by integrating its CoCreate and SAP environments to share information as a product changes from development into the manufacturing phase of its lifecycle.
Agilent Technologies Inc.
Filed Under: 3D CAD, Software