Convergent Modeling: New modeling paradigm in Siemens PLM’s NX 11 converges facets, surfaces, solids

In its recently launched NX 11 product engineering software, Siemens PLM introduced a new modeling paradigm it calls Convergent Modeling. This new technology “greatly simplifies the ability to work with geometry consisting of a combination of facets, surfaces and solids, without the need for time-consuming data conversion,” the company says. Billed by Siemens as first-of-its-kind technology, Convergent Modeling is designed to deliver three key benefits: “to help engineers optimize part design for 3D printing, speed up the overall design process, and make reverse engineering a far more common and efficient practice in product design.”

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Facet model of knee joint with b-rep surgical guide, modeled in single environment. Source: Siemens PLM

NX 11 also includes multiple enhancements throughout the integrated CAD/CAM/CAE solution suite, such as “next-generation 3D CAE, powered by the recently announced Simcenter 3D software, and improved CAM productivity with tools like robotics machining and hybrid additive manufacturing to help improve productivity.”

Siemens PLM vice president for Product Engineering Software Joe Bohman remarked, “Siemens continues to invest in our core products to deliver innovative functionality such as Convergent Modeling, which we believe will be a game changer for digital product design. We anticipate Convergent Modeling will be a critical tool for efficiently working with facet geometry. This new one-of-a-kind technology is expected to provide huge savings in time and cost and help eliminate the error-prone rework phase, common when working with scanned geometry. It also removes the limitations associated with traditional CAD modeling when it comes to optimizing parts for 3D printing. NX11 simplifies the design process and supports the evolution of additive manufacturing to help companies realize a whole new level of creativity in product development.”

Built on Convergent Modeling technologies first rolled out in Parasolid v28.1

The new NX capabilities are built on the Convergent Modeling technologies first rolled out in Parasolid v28.1, which enable facet models to be created and modified in Parasolid using a large selection of the established functions used on classic b-rep models. Applications benefit from the ability to deploy a common set of familiar modeling tools, regardless of the geometry format, using a single geometric modeling component, the company says. Key capabilities and advantages of this new Parasolid technology as described by Siemens:

“Integrated Convergent Modeling”

  • A single geometric modeling component with a unified set of modeling functions for facet models and classic b-reps.
  • Genuinely seamless integration, with no delegation to an add-on modeling component.
  • No need to convert between b-reps and facets.
  • A single supplier offering the same high-quality technical support and frequent release schedule with no additional supplier administration, contracts or integration/maintenance costs.

“Powerful Convergent Modeling”

  • Full power of Parasolid modeling on faceted models.
  • Industry-proven performance, reliability and quality.

“Flexible Convergent Modeling”

  • Freedom to model with classic b-rep or facet models, or a combination of the two.
  • Flexible licensing options—license the package level needed.
New freedom to design for additive manufacturing

Product design is partially based on available materials and manufacturing approaches, Siemens notes. New techniques such as additive manufacturing open the door to creating designs with forms and shapes that can provide higher levels of performance. “Of course, traditional CAD technologies are built to support traditional manufacturing methods and have limitations when trying to optimize designs for additive manufacturing,” the company says. In NX 11, Convergent Modeling “removes these limitations by giving designers the flexibility to rapidly create new optimal shapes leveraging the materials and techniques made available through additive manufacturing.”

Simplified process for working with scanned data

Similarly, Convergent Modeling simplifies the process of working with scanned data. Engineers in more and more industries—medical devices, automotive, consumer goods, many others—are using scanned 3D data as part of the design process. This reverse engineering of existing designs has traditionally been an expensive and tedious process, Siemens notes, because the scanned data required a time-consuming manual conversion of the resulting faceted geometry into surface and solid form before it could be used for further modeling. Irregular shapes in particular required extensive rework in order to be used for 3D printing, mold design, analysis and other purposes. This traditional reverse engineering process could take days or weeks to complete. “Convergent Modeling greatly reduces the need for this rework by bringing the scanned data in as facets that can be worked directly in NX 11, so there is no need to map surfaces, create solids, or do any other manual shape creation,” the company explains.

Convergent Modelling allows users to immediately begin using scanned data to create molds based on the shape, include it in an assembly, analyze it, or perform any other normal CAD operation. This, combined with the new 3D Print function in NX11 that enables users to 3D print designs directly from NX, significantly simplifies the additive manufacturing process, according to Siemens. This new breakthrough scan, edit and print workflow uses the new Microsoft 3D print capabilities and supports the 3MF format to help ensure wide compatibility.

Simcenter 3D now powers all NX simulation capabilities

NX 11 also includes several other significant enhancements. Simcenter 3D now powers all simulation capabilities in NX for predicting product performance. Siemens says Simcenter 3D, which is also available as a standalone application, “provides NX users with a seamless experience as they move between design and simulation tasks. It speeds the simulation process by combining best-in-class geometry editing, associative simulation modeling and multidiscipline solutions embedded with industry expertise. Fast and accurate solvers power structural, acoustics, flow, thermal, motion, and composites analysis, as well as optimization and multi-physics simulation. For NX 11, Simcenter 3D introduces new capabilities for modeling and simulation of rotating machinery, a new environment for interior and exterior acoustics, and significant enhancements in damage analysis of composite structures.” See also Predictive engineering analytics: Simcenter unifies, advances Siemens PLM’s simulation/test portfolio.

Advanced manufacturing technologies

Advanced technologies in NX 11 for manufacturing “will help manufacturers expand machining flexibility and accuracy, reduce programming time, and improve part quality,” the company says. New robotic programming capabilities in NX CAM extend the range of machining applications on the shop floor, enabling precise machining of large and complex parts using six-plus-axis robots. Robotic machining automates manual operations, including polishing and deburring, improving repeatability to help deliver high quality parts. In addition, the enhanced feature-recognition capability automates NC programming of parts with many holes, to reduce programming time by up to 60 percent. NX CMM Inspection Programming’s new high-speed cycle takes measurements by moving only the head, rather than the CMM linear axes. The new head-touches method improves accuracy and speeds up inspection cycles by up to three times, the company reports.