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SPAcstr Global Function api_make_trface

outcome api_make_trface(	const SPAposition&	`center`,
	const SPAunit_vector&	`normal`,
	double	`major`,
	double	`minor`,
	const SPAposition&	`pnt`,
	double	`uf`,
	double	`ut`,
	double	`vf`,
	double	`vt`,
	FACE*&	`face`,
	AcisOptions*	`ao`	`= NULL` )

Creates a face that is a portion of a torus.

Role: The torus is defined by a plane specified by a point and unit vector normal to the plane. The major radius gives the distance from the center to the spine curve lying in this plane around which a circle having the minor radius is swept to define the torus.

Three classes of tori can be specified: donut, apple, or lemon depending on the relative magnitudes of the major and minor radii. Also, the signs of the of the radii are significant in defining the shape of the tori and the orientation of the outward surface normals.

The point defining the origin of a parameterization scheme on the torus is projected onto the plane of the torus. The intersection of the torus and the line from the center towards this point that is farthest from the center define the (0, 0) of the parameterization scheme. The boundaries of the face lie on isoparametric curves specified by angles around the tube and around the spine. Also, the angles along and around the spine increase following the right hand rule.

Limitations: The range of angles (vf to ut) must be <= 2 pi.
Regular torus - donut: The range of (uf to ut) must be <= 2 pi.
Apples and lemons: the values of the uf and ut must be within the angle acos(fabs(major)/fabs(minimum)) {singularity points}.

Values larger than that are trimmed to the singularity.

Effect: Changes model

Journal: Not Available

Parameters:

center: center of the torus.
normal: normal axis of the torus.
major: major radius of the torus.
minor: minor radius of the torus.
pnt: point defining origin of parameterization.
uf: start angle and end angles.
ut: in u direction (in radians).
vf: start angle and end angles.
vt: in v direction (in radians).
face: toroidal face returned.
ao: acis options.

This object is included in the file: cstrapi.hxx