NURBS
NURBS (Non-Uniform Rational B-Splines) is a mathematical model used to represent freeform curves and surfaces with high precision. NURBS surfaces can describe both standard analytic shapes (lines, circles, conics) and complex sculpted geometry through a network of weighted control points, making them the standard for Class A surface modeling in automotive, aerospace, and consumer product design.
In context
When a Class-A automotive surface designer creates a hood in CATIA's Generative Shape Design, the resulting geometry is stored as NURBS surfaces — allowing downstream Abaqus simulation to evaluate panel stiffness using the exact mathematical surface rather than a faceted mesh approximation. NURBS also enables the exact representation of circles and cylinders in CAD, which is why a pipe cross-section in engineering drawings is mathematically exact, not a polygon approximation.
Why it matters
NURBS is what makes high-precision surfacing in CAD tractable: a single mathematical formulation handles everything from a precise hole to a curved car body panel. STEP, IGES, and most CAD-to-CAM pipelines hand off geometry as NURBS, which is why NURBS support quality in a kernel directly determines how cleanly a model survives export to a downstream manufacturing or simulation system.
External References
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Cite this definition
Finocchiaro, Michael. “NURBS.” DemystifyingPLM PLM Glossary, 2026, https://www.demystifyingplm.com/glossary/nurbs-non-uniform-rational-b-splines