<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><div>Hi I am trying to understand the pull code with the tutorial i found from here. <br><br><span><a target="_blank" href="http://www.csc.fi/chem/course/gmx2007/">http://www.csc.fi/chem/course/gmx2007/</a></span><br><br>i have a confusion about it. <br><br>when i put one atom in the reference group and the other atom in the group_1, doesn't it mean that, the pulling should be in one direction? But the result i am getting, it looks like it is pulled in both way. <br><br>and if I wanted to pull with a group of atom, should I just put the atoms in group_2, group_3, in this manner?<br><br>can any one help me with this? <br><br><br>Thanks in advance.<br><br>Tawhid<br></div></div></body></html>