用坐標系操作來繪制圓：

命令流:

CSWPLA,11,1,0.5,1
/PREP7
K,1,-5
K,2,5
L,1,2
CSYS,0
LSYMM,Y,1,,,,0,0
lglue,all
al,1,3

詳細解釋:

查閱幫助得知:

1.CSWPLA：
/*
CSWPLA, KCN, KCS, PAR1, PAR2

Defines a local coordinate system at the origin of the working plane.


KCN
Arbitrary reference number assigned to this coordinate system. Must be greater than 10. A coordinate system previously defined with this number will be redefined.

KCS
Coordinate system type:

0 or CART --
Cartesian

1 or CYLIN --
Cylindrical (circular or elliptical)

2 or SPHE --
Spherical (or spheroidal)

3 or TORO --
Toroidal


PAR1
Used for elliptical, spheroidal, or toroidal systems. If KCS = 1 or 2, PAR1 is the ratio of the ellipse Y-axis radius to X-axis radius (defaults to 1.0 (circle)). If KCS = 3, PAR1 is the major radius of the torus.

PAR2
Used for spheroidal systems. If KCS = 2, PAR2 = ratio of ellipse Z-axis radius to X-axis radius (defaults to 1.0 (circle)).

*/ 可以知道第一句是定義了一個圓柱坐標系
第三四句就創建了橢圓的兩個端點.
第五句創建連接兩個點構成一條線（因為是圓柱坐標系，所以繪制的線不是直線了：）
csys，0切換到整體坐標系.
最后%26quot;LSYMM,Y,1,,,,0,0%26quot;一句進行對稱繪制.
然后lglue,all把兩條線連接起來，最后一句繪制橢圓面.
這個里面比較難以理解的是用l,1,2命令連接兩點得到的不是直線而是曲線.