实体定义
二维曲线(GfcCurve2d),是各种二维线段的基类。
继承关系
GfcRoot
└
GfcGeometry
└GfcCurve2d
├
GfcLine2d
├
GfcArc2d
├
GfcEllipse2d
├
GfcNurbsCurve2d
├
GfcPreimageCurve2d
├
GfcSinCurve2d
├
GfcSpiralLine2d
└
GfcOffsetCurve2d