Dear Chimera-users I have a problem that I'm not sure can be solved in Chimera, but I thought I'd put the questions out there. Have search the archives, but couldn't turn up anything really relevant. I have a set of pdb-structures (snapshots of the same protein from a molecular dynamics simulation). The protein sits in a membrane and has a bunch of floppy loops that protrude into the solvent region. My aim is to be able to make a plot (in 3D) of the space explored by these loops over the entire simulation, essentially to see if some regions of space are preferred over others. What I thought of doing was to calculate the surface regions traced out by the loops projected on the half-sphere formed by the membrane in the x-y-plane and z>0. I hope that makes sense! Is something like this even possible in Chimera, or should I look elsewhere for a solution (perhaps inventing my own method?) Thanks /Per Larsson, University of Virginia