Question

圆在MxDrawCAD控件下为一个实体类：

class ARXDLL McDbCircle : public McDbCurve

通过调用

// -------------------------------------------------------------------------
// Summary:
//  构造函数
// -------------------------------------------------------------------------
McDbCircle();
// -------------------------------------------------------------------------
// Summary:
//  构造函数
// Parameters:
//  cntr - 圆的中心点
//  nrm  -   暂没有使用
//  radius -   圆的半径
// -------------------------------------------------------------------------
McDbCircle(const McGePoint3d& cntr, const McGeVector3d& nrm, double radius);

初始化，或使用默认的构造函数，如：

	{
		McDbCircle * pEnt = new McDbCircle(McGePoint3d(0, 0, 0), McGeVector3d(), 10);
		SetEnt(256, _T("ByLayer"), pEnt);//颜色随层，线型随层
	}
	{
		McDbCircle * pEnt = new McDbCircle(McGePoint3d(10, 0, 0), McGeVector3d(), 10);
		SetEnt(0, _T("ByBlock"), pEnt);//颜色随块，线型随块
	}
	{
		McDbCircle * pEnt = new McDbCircle(McGePoint3d(10, 0, 0), McGeVector3d(), 10);
		SetEnt(2, _T("BORDER"), pEnt);//黄色，BORDER线型
	}