Packing amorphous cell

Dear all,

I have a problem in packing amorphous cell. I have build a 3d box and put 4 chains in the box as you can see in below figure. After packing the position of chains changed.would you say me why and what should i do?Because i need them on that specific position.

One time i fixed them and then did packing but they moved again.

Regard

SJN

Figure1.png