$GRAB的用法是怎樣的？我看了例子還是不明白，請大蝦解釋一下下面的例子，$GRAB的那幾個(gè)參數(shù)到底是什么意思呢？謝謝~ aIT0t0.  
 pb<eg,  
M+-odLltw  
SYSTEM NEW %b pQ=  
RESET ixy:S1pI  
%N\45nYU:  
EMITTING DISK Z 0 1 1 1000 K\}qYdPF  
EP4?+"Z  
STATS POSITION \Ogs]4  
1Xcj=I-4  
mr>E'd.'  
$GRAB 'Centroid:' 0 1  XCENT YCENT ZCENT n%2c<@p#  
H(?+-72KX  
$REG XCENT YCENT ZCENT  (CAVOed  
`j2|aX %Z*  
RETURN

我今天也碰到了相同的問題，我是這麼認(rèn)為的： i(kx'ua?  
先看運(yùn)行命令後的提示： GI>(S  
--- SYSTEM NEW 
X^rFRk  
--- RESET \jb62Jp  
--- EMITTING DISK Z 0 1 1 1000 g
_rk_4]  
Total flux in rays created by this emitter is 1.000000 G8'  
--- STATS POSITION /x<uv_"  
Current Statistics for Object 0 -
3p]\l ]=  
Total Flux = 1.00000 from 1000 rays (100.00%) D=K{(0{"/,  
X Y Z VQ8Fs/Zt!  
Centroid:                  0.110887E-01      0.479158E-01        0.00000 f4VdH#eng`  
RMS Deviation:        0.485753              0.510739                0.00000 M(I%QD  
Maximum Spread:  -.997810                -1.02958                  0.00000 Dl,sl>{  
                              to 0.976937              0.945055                  0.00000 
% bKy  
--- $GRAB 'Centroid:' 0 1 XCENT YCENT ZCENT B>c2 *+Bk  
--- $REG XCENT YCENT ZCENT "&o"6ra}  
Z~: XCENT 1.10887E-2 eZD"!AT  
Y~: YCENT 4.79158E-2 ia,5=SKJ  
X~: ZCENT 0 >v