A CAD model that looks finished and a CAD model that’s ready to mesh and simulate are not the same thing. The gap between them is usually invisible until a meshing tool chokes on it, or worse, until it meshes cleanly but produces a model that quietly misrepresents the part. Here are five things worth checking before a model goes to simulation.
None of these are hard to fix individually. What makes them costly is finding them late, after a mesh has already been built and a solver run has already failed or, worse, quietly succeeded with results nobody double-checked. Geometry cleanup up front is one of the least glamorous parts of the CAE pipeline and consistently one of the highest-leverage.
We handle geometry cleanup, mid-surfacing and defeaturing as a standard part of our FE Meshing service, whether the CAD came from us or arrived from your team. Send us a model if you’d like a second set of eyes on it.
Every simulation team eventually settles into a favorite solver, and there’s a good reason for that: licensing costs, team familiarity, and existing model libraries all push toward standardizing on one platform. That’s a reasonable operational decision. It’s a less reasonable technical one, because LS-DYNA, PAM-CRASH, Nastran and Abaqus were built to answer different kinds of questions well, and defaulting to whichever one you have open can quietly shape the analysis itself.
Explicit solvers like LS-DYNA and PAM-CRASH are built for short-duration, highly nonlinear events, crash, impact, drop testing, where large deformations and contact happen in milliseconds. Implicit solvers like Nastran and Abaqus are built for the opposite: linear and nonlinear structural analysis, static and dynamic loading, modal and fatigue studies, where the physics play out over a longer time scale and stability matters more than raw speed per step. Running a crash event through an implicit solver, or a slow structural fatigue study through an explicit one, is technically possible and practically painful, you’ll fight the solver instead of answering the engineering question.
For a lot of mainstream linear structural analysis, Nastran and Abaqus produce comparable results, and the choice comes down to team familiarity, existing model libraries, or downstream reporting requirements rather than any real technical edge. This is exactly the kind of decision where “whichever license we already have” is a perfectly fine answer. The mistake isn’t picking a default solver, it’s never questioning the default when the problem in front of you doesn’t fit it.
Being solver-agnostic isn’t a marketing position, it changes how a project gets scoped from day one. Instead of asking “how do we make this work in the solver we have,” the first question is “what does this physics actually need.” Most of the time that lands on a familiar answer. Occasionally it doesn’t, and that’s precisely the case where solver flexibility saves a project from a bad result delivered on time rather than a good one delivered slightly later.
Not sure which solver fits your next project? See our Multi-Solver Simulation service or talk to us about the specifics.
Every meshing decision is a trade-off between accuracy, run time and how much manual cleanup you’re willing to do. Shell, tetra and hexa elements each solve that trade-off differently, and picking the wrong one doesn’t usually fail loudly, it just quietly costs you solver time, mesh quality warnings, or results you can’t fully trust. Here’s how we think about the choice.
If a part’s thickness is small relative to its other dimensions, sheet metal panels, brackets, thin-walled housings, shell elements are almost always the right call. They represent the mid-surface of the part with 2D elements carrying a thickness property, which keeps element counts (and solve times) far lower than trying to fill a thin volume with 3D elements. The catch is upstream: shell meshing depends on clean mid-surface extraction, and geometry with variable thickness, fillets or messy CAD history can turn that step into the most time-consuming part of the job.
Tetrahedral elements are the default answer for geometrically complex, chunky, or irregular parts, castings, cast housings, organic shapes, anything where a clean hexahedral grid isn’t realistic without heavy simplification. Modern tetra meshers handle complex geometry with far less manual intervention than hexa meshing, which makes them the practical choice when turnaround matters more than squeezing out the last bit of solver efficiency. The trade-off is element count and, for some solvers, a stiffer response unless second-order (mid-side node) elements are used.
Hexahedral elements give the best accuracy-per-element of any mesh type, and they’re what we reach for on high-fidelity structural and crash models where result quality can’t be compromised: crash boxes, chassis members, anything with a load path that needs to be captured precisely. The cost is time. Building a clean hex mesh usually takes longer and more manual effort than tetra, which is exactly why it’s reserved for the parts of a model where that investment actually pays off, not applied uniformly across an entire assembly.
In practice, most real assemblies use all three: shells for the sheet-metal body, tetra for the cast or complex brackets, hexa for the handful of components where the load path is the whole point of the analysis. The mesh strategy should follow the question the simulation is trying to answer, not the other way around. Whatever the mix, every mesh we build gets checked against solver-specific quality criteria, Jacobian, warpage, skewness, before it’s handed off, because a mesh that looks fine visually can still quietly fail those checks.
Want a second opinion on a meshing strategy for an upcoming project? Get in touch, or see the full detail on our FE Meshing service.