All Frameworks  Class Hierarchy  This Framework  Indexes

SPAkern Global Function bs3_surface_prin_curv

void bs3_surface_prin_curv(	SPApar_pos const&	`uv`,
	bs3_surface	`bs`,
	SPAunit_vector&	`u1`,
	double&	`c1`,
	SPAunit_vector&	`u2`,
	double&	`c2`)

Evaluates the principal axes of curvature and corresponding curvatures of a three-dimensional B-spline surface at a given uv.

Role: The sign and order of the principal axes are not significant. The sign of the curvature value indicates whether the surface is convex or concave with respect to the normal direction, which is considered to point outward from the region bounded by the surface. A convex surface (one that curves back from the outward normal direction) has positive curvature, a concave one has negative curvature.

Errors: Returns without setting anything if the input surface is NULL.

Effect: Read-only

Parameters:

uv: given parameter point.
bs: given surface.
u1: returns first principal axis.
c1: returns first curvature.
u2: returns second principal axis.
c2: returns second curvature.

This object is included in the file: sp3srtn.hxx