[lammps-users] Group Defination under some geometry

Hi Axel,
Thanks for your quick reply.
I am aware of region and addforce command. But problem is once I have defined the group Z>10, atoms within the group will be fixed so force will be always on those atoms no matter what z coordinate they have(as manual explains).
But I want to have something that for every step it should check whether atom has Z>10 and should apply force only on those which have Z>10A.

Hi Axel,
Thanks for your quick reply.

I am aware of region and addforce command. But problem is once I have defined the group Z>10, atoms within the group will be fixed so force will be always on those atoms no matter what z coordinate they have(as manual explains).
But I want to have something that for every step it should check whether atom has Z>10 and should apply force only on those which have Z>10A.

but that is what i already suggested!

do i have to write this in sanskrit or some other "divine" language
for it to sink in?

*nothing* restricts you to have the z > 10A definition on the fix group
you apply the force on initially. with the region keyword the force is applied
to the *intersection* of region and group. if you choose the group "all"
then effectively *only* the region definition is applied.

that is it.

axel.

p.s.: please always send plain text formal mails to mailing lists. thanks.