Hi: I prepared with the zone command a model (#0) of a protein partly immersed into a hydrated lipidic bilayer (cut-and-paste from the two models from the zone command). Now I would like to solvate with water the part of protein which protrudes out of the bilayer. Water is single-point (coarse-grain simulations) indicated in model #0 as ATOM 2724 W W 2060 45.420 3.750 23.380 1.00 0.00 W and in the pdb file of the water block (model #1) to be added ATOM 27558 W W 5018 84.320 142.862 11.262 1.00 0.00 Once model #0 and model #1 are superimposed, clearly the zone command does not distinguish W from the two models. How could the zone command be made working now? I renamed W to WAT in model #1 but the zone command does not recognizes WAT under such circumstances. Not yet found a way out, which should be simple. Thanks for suggestions. (solvating model #0 with programs from the MD suite also solvates what it should not; this is why I am trying with CHIMERA) francesco pietra