| | Describes a circle in 3D space.
A circle is defined by its radius and positioned in space
with a coordinate system (a gp_Ax2 object) as follows:
- the origin of the coordinate system is the center of the circle, and
- the origin, "X Direction" and "Y Direction" of the
coordinate system define the plane of the circle.
This positioning coordinate system is the "local <br>
coordinate system" of the circle. Its "main Direction"
gives the normal vector to the plane of the circle. The
"main Axis" of the coordinate system is referred to as
the "Axis" of the circle.
Note: when a gp_Circ circle is converted into a
Geom_Circle circle, some implicit properties of the
circle are used explicitly:
- the "main Direction" of the local coordinate system
gives an implicit orientation to the circle (and defines
its trigonometric sense),
- this orientation corresponds to the direction in
which parameter values increase,
- the starting point for parameterization is that of the
"X Axis" of the local coordinate system (i.e. the "X Axis" of the circle).
See Also
gce_MakeCirc which provides functions for more complex circle constructions
Geom_Circle which provides additional functions for
constructing circles and works, in particular, with the
parametric equations of circles
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1.6.3