一个框包含直线和圆弧怎么把他们连成一个整体？

llp0420

AcDbLine*Plinep=new AcDbLine(ptStart11,ptEnd11);
   AcDbLine*Plinec=new AcDbLine(ptStart12,ptEnd12);
   AcDbLine*Plined=new AcDbLine(ptStart13,ptEnd13);
   AcDbLine*Plinef=new AcDbLine(ptStart14,ptEnd14);
   AcDbLine*Plinee=new AcDbLine(ptStart11,ptEnd14);
AcDbCircle * pCirca1 =new AcDbCircle(pt15,normal,2.25);
   AcDbCircle * pCirca2 =new AcDbCircle(pt16,normal,2.25);
   AcDbCircle * pCirca3 =new AcDbCircle(pt17,normal,2.25);
   AcDbCircle * pCirca4 =new AcDbCircle(pt18,normal,2.25);
   AcDbCircle * pCirca11 =new AcDbCircle(pt15,normal,4);
   AcDbCircle * pCirca22 =new AcDbCircle(pt16,normal,4);
   AcDbCircle * pCirca33 =new AcDbCircle(pt17,normal,4);
   AcDbCircle * pCirca44 =new AcDbCircle(pt18,normal,4);
怎么把这些连成多段线

llp0420

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