| | Describes an ellipse in 3D space.
An ellipse is defined by its major and minor radii 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 ellipse,
- its "X Direction" defines the major axis of the ellipse, and
- its "Y Direction" defines the minor axis of the ellipse.
Together, the origin, "X Direction" and "Y Direction" of
this coordinate system define the plane of the ellipse.
This coordinate system is the "local coordinate system"
of the ellipse. In this coordinate system, the equation of
the ellipse is:
X*X / (MajorRadius**2) + Y*Y / (MinorRadius**2) = 1.0
The "main Direction" of the local coordinate system gives
the normal vector to the plane of the ellipse. This vector
gives an implicit orientation to the ellipse (definition of the
trigonometric sense). We refer to the "main Axis" of the
local coordinate system as the "Axis" of the ellipse.
See Also
gce_MakeElips which provides functions for more
complex ellipse constructions
Geom_Ellipse which provides additional functions for
constructing ellipses and works, in particular, with the
parametric equations of ellipses
More...
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1.6.3