[Chimera-users] Chimera application questions

To whom may concern, This is Yanhe Zhao from UT Southwestern Medical Center. I have to question when use Chimera as below, hopefully someone could do me a favor to answer it. 1, my crystal structure have four copies in one Asymmetrical structural unit. When I try to combine two of them by selection and combine command, always combine all of them. I pretty sure that I only select two of them; 2, I got one PDB from SASDB, how can I show it as a density map like CryoEM? When I open, it's shown as lines-like map so as to which couldn't be used for docking. I really appreciate it if someone could do me this favor. Thanks a lot. Best, Yanhe