Let’s Talk About Implicit Modeling

After a busy week at Formnext 2025, where implicit modeling was once again the talk of the show, we caught up with Wesley Essink, a key member of the Altair® Inspire™ team. He helped us debunk some modeling myths and shares his insights into the benefits of modern engineering design, as illustrated by a recent design-development study by Etteplan in Finland.

Q: How is implicit modeling impacting engineering design?

A: Implicit modeling is reshaping engineering design by shifting the focus from manually constructed feature-based geometry to flexible, mathematically defined representations. This makes models far more resilient to change; Modifying a dimension or constraint no longer risks breaking the entire design history.

As a result, teams can iterate faster, explore more design alternatives, and maintain cleaner, more adaptable models throughout the product development cycle. I think implicit modeling is pushing engineering design toward a future where complexity is no longer a barrier but a creative advantage.

Q: How does implicit modeling compare with traditional modeling approaches?

A: A traditional computer-aided design (CAD) approach defines geometry using explicit boundaries (edges, surfaces, and vertices). This means that adding more features or complexity to a model requires re-evaluating complex surface patches and time-consuming intersections between various geometries. Operations like Booleans, fillets and sweeps can fail due to self-intersections or coincident surfaces.

Implicit modeling takes a different approach, by defining geometry as a set of functions or equations that return the distance to the nearest surface, the nearest surface naturally falls out everywhere the resulting distance is zero. This means that we can create highly complex topology very efficiently as we don't need to explicitly define all of the branches and surface patches individually. Evaluating geometry this way opens the door to the ability to seamlessly blend shapes, embed functional gradients, and optimize internal structures with new mathematical structures like lattices.

Q: Is implicit modeling going to replace traditional CAD modeling?

A: In my opinion, implicit modeling isn't positioned to replace traditional CAD because each approach excels at different parts of the design process. Traditional CAD remains unmatched for creating precise, dimension-driven components, defining manufacturing features, and producing drawings that align with established engineering workflows.

Implicit modeling shines when handling complex, organic geometry, and rapid iteration, areas where traditional CAD can become cumbersome or fragile. I think an ideal workflow uses a variety of modeling approaches to maintain precision where it matters, while unlocking new levels of creativity and performance where complexity is an advantage. Together, they form a complementary rather than a competitive toolkit, enabling more robust and innovative design outcomes.

Q: How has Altair taken an integrated simulation-driven design approach to implicit modeling?

A: After considering the benefits of each type of geometry representation, instead of creating a pure implicit modeling solution, at Altair, we decided to add implicit as a new geometry type to sit alongside the other existing modeling types (Brep/Parasolid, PolyNURBS, Mesh). The aim was to make implicit modeling feel familiar and intuitive to design engineers already experienced with traditional CAD modeling tools. Each geometry type speaks to each other and together works seamlessly in a single parametric workflow.

To overcome difficulties encountered by engineers using implicit, Altair created a fully integrated simulation-driven design for manufacturing solution. The goal is to make simulation accessible from the start of development, driving innovation and empowering designers to make informed decisions early and with ease.

If you want to take a deep dive into how we believe we are reshaping product development with implicit modeling in Inspire, I'd recommend watching the following YouTube video from Jousef Murad's podcast: https://www.youtube.com/watch?v=BsIsAT5iVVk.

What are the benefits for design and manufacturing engineers?

There are quite a few advantages I can think of:

• Faster iterations and modifications: Because implicit models don't rely on a fixed topology and can be evaluated efficiently on the GPU, design engineers can change parameters without worrying about failures, such as broken fillets or edge mismatches. Less time fixing faults leads directly to more efficient design iteration and exploration.
• Linking geometry to data: Owing to its functional approach to geometry creation, implicit modeling is perfectly positioned to use external data, such as simulation results, real-world measurements or AI-generated data, to drive the parameters used in implicit functions.
• Geometry reconstruction: The ability to locally sculpt implicit fields, smoothly blend or even morph between different various geometries makes implicit modeling a great tool for taking topology optimization results or scan data to recreate a smooth CAD surface geometry with the help of PolyNURBS.
• Lightweighting geometry: Complex lattice structures allow components to shed mass without compromising performance. By adding functional gradients to the lattice, geometries can be tailored to specific load cases, ensuring optimal use of material.
• Automation and customization: Implicit functions are constructed like recipes and can be easily scripted to automate workflows or even extend existing functionality with custom implicit functions defined by a user.

As Altair's Jaideep Bangal put it: "Engineers aren't meant to spend days creating meshes, they're meant to solve real-world problems". I would also check out the podcast episode with Jousef Murad, where Jaideep reflects on how implicit modeling is helping engineers move beyond the limits of traditional CAD: https://www.youtube.com/watch?v=kj_UWS9xbi8.

But what does this mean in real world engineering?

There's no shortage of discussion around the elegant organic solutions that implicit modeling, coupled with additive manufacturing, can offer across all industries, from custom medical implants to serial production aerospace components.

Here, take a look at a project conducted by Etteplan in Finland regarding an extension boom-end component of a tree harvester: a large, heavy part conceived to resist both static and dynamic forces throughout its arduous working environment.

With the power of Altair's simulation-driven design for manufacturing solution, the Etteplan team revisited an existing design to explore an additive manufacturing option, as well as a cast metal part.

• Additive manufacturing: In the hands of Etteplan experts in AM design, AM processes, materials, and FEM, the redesigned AM part not only met all load constraints and reduced the weight by 66%, but also yielded an easily adaptable optimization and design workflow for other manufacturing processes, in addition to opening new opportunities for lightweighting adjacent parts and assemblies.
• Cast metal part: Etteplan applied their easily adaptable optimization and design workflow to further utilize their use of Altair's simulation-driven design solution for manufacturing (DfM) for the optimal design of a cast part. By targeting the design optimization workflow for casting, a weight reduction of 53% was attained, along with implementation of new scripting and workflow automation tools to significantly speed up simulation and the overall design process.

Check out this video with Erin Komi, an AM expert from Etteplan talking about the project at Formnext.

This real-life example perfectly illustrates a major benefit over competitor DfM software. Altair offers a fully integrated simulation-driven design approach for both traditional (casting, extrusion, forming, molding) and additive (metal binder jetting, powder bed fusion (also known as SLM)) manufacturing processes.

Together, Altair's extensive software tools in the hands of Etteplan engineering experts is building a competitive future for its worldwide customers across all engineering sectors.

Visit https://altair.com/inspire to learn more about Inspire and try its comprehensive simulation-design for manufacturing solution for yourself, here.