I would like to confine a population of particles to the surface of a cylinder. (1) One way I can think to do this is to apply a harmonic restoring force to these particles holding them at a fixed distance from an axis. (2) Alternatively I could build a cylindrical "sticky" (a modified LJ 12-6 ?) wall that all particles are attracted to. (3) I suppose I could also build a cylinder out of a population of sticky fixed particles, but I would be concerned that the roughness of that wall might affect how the non-fixed particles interact with the wall.
(3) seems possible within the command library. (1) and (2) seem outside the available command library and may require modifying the source code. Comments?