看下這個 [?;`x&y~y  
EDGES !! or CURVE *6NO-T; -  
  R=5  !! Vertex radius of curvature `-~`<#E[  
  K=-1 !! Conic constant v2IEJ  
  H=5  !! Outer aperture height MinbE13?U  
  O=0  !! Inner obscuration height [_j6cj]  
CONIC X 0, 0 0 -2*R 1 0 K+1, Y (O) (H) !!構建拋物線 lo"j	)Zt  
SHIFT Y 1  !!偏移 6_W <hevI  
SWEEP AXIS 360 Z  !!旋轉