Signed Distance Field (SDF)
A scalar function F(x, y, z) defined over all of 3D space that returns the shortest Euclidean distance from any point to the nearest surface — negative inside the solid, positive outside, zero on the boundary. nTop and Cognitive Design Systems use SDF as their native geometry representation.
Why it matters
Boolean operations on SDFs reduce to elementary min/max math (union = min; intersection = max; difference = −max), making them mathematically guaranteed never to fail. Offsetting a shape is as simple as raising the iso-level — a trivially robust operation compared with B-rep offset, which frequently fails.
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External References
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Cite this definition
Finocchiaro, Michael. “Signed Distance Field (SDF).” DemystifyingPLM PLM Glossary, 2026, https://www.demystifyingplm.com/glossary/signed-distance-field-sdf