Defined in File Ifc4x3_rc1.h
IfcEllipse: public Ifc4x3_rc1::IfcConic¶
Definition from ISO/CD 10303-42:1992: An ellipse (IfcEllipse) is a conic section defined by the lengths of the semi-major and semi-minor diameters and the position (center or mid point of the line joining the foci) and orientation of the curve. Interpretation of the data shall be as follows:
C = SELF\IfcConic.Position.Location
x = SELF\IfcConic.Position.P
y = SELF\IfcConic.Position.P
z = SELF\IfcConic.Position.P
R1 = SemiAxis1 R2 = SemiAxis2 and the ellipse is parameterized as:
The parameterization range is 0 £ u £ 2p (or 0 £ u £ 360 degree). In the placement coordinate system defined above, the ellipse is the equation C = 0, where
The positive sense of the ellipse at any point is in the tangent direction, T, to the curve at the point, where
NOTE Corresponding ISO 10303 entity: ellipse. Please refer to ISO/IS 10303-42:1994, p. 39 for the final definition of the formal standard.
HISTORY New class in IFC Release 1.0
Figure 280 illustrates the definition of the IfcEllipse within the (in this case three-dimensional) position coordinate system.
Figure 280 — Ellipse geometry
The first radius of the ellipse which shall be positive. Placement.Axes gives the direction of the SemiAxis1.
The second radius of the ellipse which shall be positive.