用坐标系操作来绘制圆：
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
详细解释:
查阅帮助得知:
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义了一个圆柱坐标系
第三四句就创建了椭圆的两个端点.
第五句创建连接两个点构成一条线（因为是圆柱坐标系，所以绘制的线不是直线了：）
csys，0切换到整体坐标系.
最后"LSYMM,Y,1,,,,0,0"一句进行对称绘制.
然后lglue,all把两条线连接起来，最后一句绘制椭圆面.
这个里面比较难以理解的是用l,1,2命令连接两点得到的不是直线而是曲线.
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
详细解释:
查阅帮助得知:
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义了一个圆柱坐标系
第三四句就创建了椭圆的两个端点.
第五句创建连接两个点构成一条线（因为是圆柱坐标系，所以绘制的线不是直线了：）
csys，0切换到整体坐标系.
最后"LSYMM,Y,1,,,,0,0"一句进行对称绘制.
然后lglue,all把两条线连接起来，最后一句绘制椭圆面.
这个里面比较难以理解的是用l,1,2命令连接两点得到的不是直线而是曲线.