


SMLib™ SMLib™ Our flagship product built upon TSNLib™ provides fully functional nonmanifold topological structure and solid modeling functionality including the ability to perform NURBS boolean operations, fillets, etc.
TSNLib™ TSNLib™ Built on top of GSNLib supporting trimmed surface representations.
GSNLib™ GSNLib™ A basic curve and surface NURBS library. GSNLib™ provides a useful interface to NLib while adding value as well. Includes curve/curve and surface/surface intersection and polygon modeling.
NLib™ NLib™ A comprehensive BSpline NURBs library fully supporting curves, surfaces, and volumes with an extensive set of shape query and construction tools.
VSLib™ VSLib™ Provides deformable modeling as part of a library using the constrained optimization techniques of the calculus of variations. The library supports several very different geometric operations.
SDLib™ SDLib™ Subdivision surface source code library that creates and modifies complex shapes with hierarchical CatmullClark surfaces.
PolyMLib™ PolyMLib™ Polygonal based geometric modeling to repair, optimize, review and edit triangle mesh models. Analyze surface properties, repair and optimize surface meshes.
Data Translators Data Translators NURBS based geometry translators to interface between Nlib™, GSNLib™, TSNLib™, SMLib™ and IGES, STEP, SAT, VDAFS, OpenNURBS, and Parasolid XT.







NLib™  The NURBS based Library 

NLib™ is a C library filled with an extensive set of robust functions that lies at the core of implementing nonuniform rational Bspline (NURBS) technology. This technology is extensively documented in "The NURBS Book" by Les Piegl and Wayne Tiller, the original authors of NLib™. 
Key Features 


• Source Code Distribution  A platform independent geometry kernel. NLib is a mature C library written and supported by industry experts.
• NURBS  Contains structures for the representation of NURBS curves and surfaces and supporting objects.
• Basics  Curve creation, surface creation.
• Advanced Surface Construction  Coons surfaces, Gordon surfaces, sweeping, skinning, least squares fitting, etc.
• Additional Functions  Curve and surface extend, reverse, projection, etc.
• General  math, vector, and geometry tools.
• Evaluation And Analysis
• Modification tools  Transformations, curve bending, surface flattening, and interactive shaping tools.
• Nurbs tools  Knot insertion, knot removal, reparametrize, make compatible, splitting, degree elevation and reduction.
• Basis  Bspline and NURBS basis functions.


Summary of Functions 

• Curve Creation
• Lines, line segments, circles, circular arcs, conics, conic arcs, and degenerate point curve.
• Global curve interpolation to points and/or derivatives cubic spline or arbitrary degree.
• Global least squares curve approximation to point data.
• Global curve approximation / data reduction with error bound specified.
• Global weighted and constrained least squares curve approximation.
• Offset curve approximation.
• Offset of a connected set of NURBS curves with trimming and filleting.
• Approximation of procedurally defined curves to within tolerance.
• Approximation of a NURBS curve with a nonrational curve.
• Mapping of a uvdomain curve onto its surface.
• Local C1continuous nonrational cubic curve interpolation.
• Local G1 or C1continuous parabolic curve interpolation.
• Local G1continuous rational quadratic curve interpolation.
• Local G1continous biarc curve interpolation.
• Local data approximation with G1continuous quadratic curves.
• Local data approximation with G1continuous cubic curves.
• Surface Creation
• Bilinear surfaces, planes, cones, cylinders, spheres, and torus.
• Extruded surfaces, ruled surfaces, and surfaces of revolution.
• Ellipsoids, elliptic paraboloids and hyperboloids of one sheet.
• Global surface interpolation to point data.
• Global least squares surface approximation to point data.
• Global surface approximation / data reduction with error bound specified.
• Local C(1,1)continuous nonrational, bicubic surface interpolation.
• Surface interpolation and approximation functions that allow specification of boundary constraints, including tangent/derivative vectors.
• Advanced Surface Creation:
• Bilinear and Bicubic Coons surface.
• Gordon surface through a compatible curve network.
• Swept surface, arbitrary trajectory curve, interpolative or approximative to within specified error bound.
• Translational swept surface.
• Swung surfaces.
• Interpolative skinning, with or without a spine curve.
• Interpolative and approximate skinning with rail curves and crossboundary continuity constraints.
• Approximate skinning with error bound specified.
• Additional NURBS curve and surface functions:
• Extend curve and surface boundary with continuity control.
• Project a point to a curve or surface to determine the corresponding parameter space point.
• Given a tangent direction on a surface, determine the corresponding direction in parameter space.
• Reverse parameter direction of a curve or surface.
• Unclamp a clamped curve or surface.
• Scale/translate the parameter domain(s) of a curve or surface.
• Various conic utilities; e.g. determine type of conic, implicit equation of conic, and geometric characteristics of a conic (vertex, radii, axes, etc).
• Make a set of curves or surfaces compatible (same degrees and knots).
• Curve and surface cleaning, with reparameterization for enhanced cleaning of piecewise Bezier curves and surfaces.
• Approximately equally spaced points on a curve.
• Approximately uniformly spaced grid of points on a surface.
• General Math and Geometric Functions:
• An extensive set of functions to perform basic geometric operations on vectors, lines, polygons, and planes; this includes distances, projections, intersections, bounding boxes, transformations, closure, and containment tests.
• An extensive set of functions to perform basic mathematical and numerical operations such as matrix algebra, solution to linear systems of equations, Horner evaluation of polynomials, polynomial root finding, and computation of the binomial coefficients.
• An extensive set of functions to check (validate) object data and set error flags; e.g. validate the data defining a curve or surface object, and check if a parameter is within valid bounds.
• Evaluation of NURBS curves and surfaces:
• Compute point and derivatives of arbitrary order on a NURBS curve.
• Compute the Frenet frame on a curve at a given point.
• Compute point and partial derivatives of arbitrary order on a NURBS surface.
• Compute the surface normal vector at a given point.
• Compute curvature on curves and surfaces.
• Compute minmax box of curves and surfaces.
• Arc length of a curve.
• Analyze curves for cusps, straight line segments, and degeneracy.
• Transformations, projections and interactive shaping tools:
• Translation, rotation and scaling of curves and surfaces.
• Project a point to a curve or surface to determine the corresponding parameter space point.
• Parallel and perspective projection of curves and surfaces onto a plane.
• Reposition curve/surface control points to obtain desired translational changes.
• Modify curve/surface weights to obtain desired perspective changes.
• Curve, polyline, and surface region warping.
• Curve and surface flattening.
• Curve bending.
• Surface axial and central bending.
• Curve and surface axial deformations: pinch, taper, twist and shear.
• Constraintbased modification via control point repositioning.
• NURBS curve and surface geometric tools:
• Knot insertion and knot refinement.
• Inverse knot insertion.
• Decomposition into piecewise Bezier form.
• Knot removal, including "cleaning" routines (data reduction) with specification of boundary constraints.
• Degree elevation and degree reduction.
• Subcurve and subsurface extraction.
• Curve and surface splitting.
• Extraction of isoparametric curves from surfaces.
• Reparameterize a curve with a linear rational function.
• Reparameterize a curve with a Bspline function.
• Reparameterize a surface with a linear rational function.
• Make curve end weights equal.
• Bspline and NURBS basis functions:
• Evaluation of rational and nonrational basis functions.
• Computation of single or all nonzero functions.
• Derivatives of arbitrary order.
• Global maximum and maximum in each span.
• Scalarvalued NURBS functions of one or two variables:
• Creation of scalarvalued NURBS.
• Functions of 1 or 2 parameters.
• Evaluation of scalarvalued functions, including derivatives of any order.
• Conversions:
• Conversion between NURBS and piecewise Bezier or polynomial spline.
• An extensive set of routines to support the evaluation and processing of Bezier and polynomial curves and surfaces.
• Tessellation of surfaces to triangles.
• Conversion of IGES curves and surfaces to NURBS form.
• Symbolic operators:
• Extract derivative curves and surfaces.
• Compute maximum bounds on magnitudes of curve/surface derivatives.
• Form linear combinations of curves/surfaces.
• Extract the surface of normal vectors to a surface.
• Compute various products of curves, surfaces, and functions.

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