IfcCircle

An IfcCircle is a curve consisting of a set of points having equal distance from the center.

NOTE  A circular arc segment is defined by using the IfcTrimmedCurve with BasisCurve being an IfcCircle.

C = SELFIfcConic.Position.Location
x = SELFIfcConic.Position.P[1]
y = SELFIfcConic.Position.P[2]
z = SELFIfcConic.Position.P[3]
R = Radius

and the circle is parameterized as

The parameterization range is 0 ≤ u ≤ 2π (0 ≤ u ≤ 360 degree).
In the placement coordinate system defined above, the circle is the equation C = 0, where

The positive sense of the circle at any point is in the tangent direction, T, to the curve at the point, where

NOTE  Entity adapted from circle defined in ISO 10303-42

XSD Specification

<xs:element name="IfcCircle" type="ifc:IfcCircle" substitutionGroup="ifc:IfcConic" nillable="true"/>
 <xs:complexType name="IfcCircle">
  <xs:complexContent>
   <xs:extension base="ifc:IfcConic">
    <xs:attribute name="Radius" type="ifc:IfcPositiveLengthMeasure" use="optional"/>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>

EXPRESS Specification

ENTITY IfcCircle
 SUBTYPE OF (IfcConic);
  Radius : IfcPositiveLengthMeasure;
END_ENTITY;