Design Nomenclature / Digital Model Making
NURBS Modeling
Also called surface modeling, spline modeling, surfacing
Building form as a patchwork of mathematically exact rational spline surfaces, each a grid of control points with a degree and a knot vector. Resolution is evaluated on demand, so the surface is exact at any zoom. The work is patch layout, and holding continuity where patches meet.
In practice
Industrial designers say “surfacing” or “Class-A”. Geometry owns the NURBS maths; this is the discipline built on it, and its failures are layout failures.
Not to be confused with
- Polygonal ModelingBuilding form from an explicit mesh of vertices, edges, and faces, moved and cut by hand. The mesh is the final surface, so its resolution is decided up front — a cylinder is faceted at whatever segment count you gave it. Fast, direct, and indifferent to mathematical exactness.
- Solid ModelingRepresenting a part as a closed watertight volume: trimmed faces stitched along shared edges, with an inside and an outside the kernel can guarantee. Volume, mass, and interference become computable. Every operation is validated against that closure, which is why a CAD boolean either succeeds cleanly or refuses.
- Subdivision SurfaceA smooth limit surface defined by a coarse control mesh — the cage — plus a refinement rule applied repeatedly. You edit the cage; the surface you see is derived from it and lies inside it. Sharpness comes from local density or explicit creases, not from a curve degree.