F16 skin geometry modeled as STEP Part 42 NURBS, predating the initial release of the Application Protocols. Built by STEP Tools Inc. with the Wright Patterson Computational Fluid Dynamics Laboratory File: f16ab_nurbs.stp Pre-STEP Part 42 File Created: 1992-09-01 (approx) Image Created: 1992-09-01 (approx) NURB surfaces, modeled as bspline surfaces with knots + rational bspline surfaces.