[lammps-users] basic problems with data file creation

Hello,

I want to create a data file with a bundle of aligned Carbon nanotubes with molecules on both ends, to simulate diffusion through the bundle.
Can anybody tell me which program to use to create SWCNT, make a bundle and end molecules to the system?

Also: Is a methane molecule simplified as an atom when running LAMMPS with lj potential forces?

Thanks in advance

Thomas