Boundary Representation (B-rep)
Boundary representation (B-rep) is the dominant method for representing solid geometry in CAD kernels. A B-rep model defines a solid by its bounding surfaces — vertices, edges, and faces — with topological relationships between them. B-rep enables precise, manufacturable 3D models that can be evaluated for mass properties, interference, and manufacturing operations, making it the standard for engineering-grade CAD.
Why it matters
B-rep is what separates engineering CAD from polygon mesh modeling: it preserves exact mathematical surfaces that machinists, simulation tools, and downstream PLM systems can trust. The investment required to build a robust B-rep kernel is also the moat that has kept the kernel market consolidated for thirty years — and the reason new CAD entrants almost always license Parasolid or ACIS rather than write their own.
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Cite this definition
Finocchiaro, Michael. “Boundary Representation (B-rep).” DemystifyingPLM PLM Glossary, 2026, https://www.demystifyingplm.com/glossary/b-rep-boundary-representation