Geometry Kernel
A geometry kernel (or geometric modeling kernel) is the foundational software library in a CAD system responsible for creating, editing, and representing precise 3D geometry. The most widely used kernels are Parasolid (developed by UGS/Siemens) and ACIS (developed by Spatial/Dassault). The geometry kernel defines the mathematical representation of surfaces and solids that the CAD application builds on top of.
In context
SolidWorks runs on Parasolid as its geometry kernel; when a SolidWorks assembly is exported to STEP and opened in CATIA (which uses Dassault's CGM kernel), translation fidelity depends on how well the STEP translator preserves Parasolid's B-rep topology — which is why kernel-to-kernel translation is a perennial interoperability challenge in PLM data exchange. CAD vendors that license their kernel from a competitor are strategically vulnerable if that competitor raises licensing terms.
Why it matters
The kernel choice silently constrains every CAD product built on top of it — what surfaces it can model, what operations are robust, what files it can exchange cleanly. It also explains why so many CAD vendors are vulnerable to a competitor: when Parasolid and ACIS are licensed from rivals, an entire industry's IP sits on a foundation it doesn't own. The geometry kernel is the most strategic component of CAD almost no end user has heard of.
Related concepts
External References
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Cite this definition
Finocchiaro, Michael. “Geometry Kernel.” DemystifyingPLM PLM Glossary, 2026, https://www.demystifyingplm.com/glossary/geometry-kernel