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.
- Gaps and unstitched surfaces. Surfaces that look joined in a shaded view but aren’t topologically connected will produce a mesh with holes, or force a mesher to bridge the gap in ways you didn’t intend. This is the single most common cause of failed shell meshing.
- Sliver faces and micro-features. Tiny fillets, chamfers or manufacturing details that don’t affect structural behaviour will still force a mesher to generate tiny, distorted elements around them, tanking mesh quality metrics for no analytical benefit. Defeaturing before meshing isn’t cutting corners, it’s what keeps the mesh focused on the geometry that actually matters.
- Inconsistent units or scale. A sub-assembly imported at the wrong scale can mesh without a single error message and still produce completely wrong mass, stiffness and contact behaviour. It’s an easy check that’s easy to skip.
- Non-manifold geometry. Edges shared by more than two faces, or surfaces with inconsistent normals, are usually leftovers from CAD history or file-format conversion. They’re rarely visible without inspection tools, and they’re a reliable way to get a mesh that looks plausible but solves incorrectly.
- Unresolved interferences between parts. In an assembly, parts that overlap slightly, common after tolerance stack-up in CAD, can silently corrupt contact definitions in the solver. What reads as a minor CAD sloppiness becomes a real simulation problem once bodies are in contact.
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.