[ESPResSo-users] Fix the orientation of a Rod

[Salvador H-V]

Hi Guys,

I am currently working with rigid rods in 3D composed of n monomers using virtual sites.

I have created an initial lattice configuration with all the rods oriented in z-direction. 

I was wondering if somebody could give me a hint of how to randomize the position of the rods but keeping the orientation. So, what I need is the rods in random positions 

but all of them with director vector parallel to axis z.

I tried with the fix command but i did not work

ESPResSo has been compiled with: ESPResSo-3.1.1

{ Compilation status { FFTW } { CONSTRAINTS } { ROTATIONAL_INERTIA } { BOND_ANGLE_HARMONIC } { GAY_BERNE } { PARTIAL_PERIODIC } { LENNARD_JONES } { VIRTUAL_SITES_RELATIVE } { EXTERNAL_FORCES } { TABULATED } { ROTATION } { SOFT_SPHERE } { VIRTUAL_SITES_NO_VELOCITY } { LENNARD_JONES_GENERIC } { ELECTROSTATICS } { BOND_VIRTUAL } { DIPOLES } }

Thanks a lot in advance.

Salvador