Local Properties of Curves and Surfaces

The "Local Properties of Curves and Surfaces" component provides algorithms for computing various local properties on a curve (in 2D or 3D space) or on a surface.

Curves are either Geom_Curve curves (in 3D space) or Geom2d_Curve curves (in the plane). Surfaces are Geom_Surface surfaces. The point on which local properties are calculated is defined by its u parameter value on a curve, and its (u,v) parameter values on a surface.

The local properties which may be queried are:

- On a 2D curve:

- the points corresponding to a minimum or a maximum of curvature

- the inflection points

- The degree of continuity of a 3D curve built by concatenation of two other curves at their junction point

- On a point of parameter u on a 2D or 3D curve:

- the point

- the derivative vectors, up to the third degree

- the tangent vector

- the normal

- the curvature, and the center of curvature

- On a point of parameter (u,v) on a surface:

- the point

- the derivative vectors, up to the second degree

- the vectors tangent to the u and v isoparametric curves

- the normal vector

- the minimum or maximum curvature, and the corresponding directions of curvature.

The "Local Properties of Curves and Surfaces" component is composed of:

- The Geom2dLProp package, which provides local properties on 2D curves

- The GeomLProp package, which provides local properties on 3D curves and surfaces

- The LProp package, which provides an enumeration used to characterize a particular point on a 2D curve.

Note: The "Local Properties of Shapes" component (see the "Topology Reference Manual") also provides these computations, but directly on "BRep shapes".