On Sep 3, 2012, at 6:28 AM, Marek Maly wrote:

Hello,

it seem to me that Chimera is not able to do H-bond analysis between
water molecules when TIP4P water model is used. Am I right or I overlooked something ?

Upon further review, I can reproduce the problem you're having.  The "extra point" of the TIP4P water (atom "EPW") is screwing up Chimera's H-bond finding.  You need to delete that "atom" ("del @epw" in the command line), then Chimera will be able to find the inter-water H bonds.

--Eric

                        Eric Pettersen

                        UCSF Computer Graphics Lab

                        http://www.cgl.ucsf.edu