General:
- switched from using the Numeric Python extension to NumPy — this may break third-party extensions
 - POV-Ray now included for direct production of shadowed images (see File... Save Image):
 
- new POV-Ray Options section of Preferences
 - ribbon style supersmooth added for use with raytracing
 - standard and 2D labels included
 - as with all raytracers, images with transparency take significantly longer to render
 - Save Image dialog changed to use pixels as the default units and to include the supersampling and print resolution settings (formerly in the Image Setup preferences)
 - Presets menu added for convenient access to display settings for interactive and publication usage scenarios
 - new built-in ribbon scaling, licorice (does not vary with secondary structure); minor changes in Chimera default scaling
 - VRML import now supports PROTOs (ie., should work for molden, and older Honig lab GRASS, output)
 - new input format MDL MOL/SDF
 - new Fetch by ID types: EDS (fo-fc) electron density difference map, PQS predicted biological unit
 - opening electrostatic potential data (APBS, Delphi, Grasp, UHBD) now starts Electrostatic Surface Coloring instead of Volume Viewer
 - compressed files (*.Z) can be recognized and opened for many input types if gzip is on the user's execution path
 - multiple models saved to a single PDB file are delimited by MODEL/ENDMDL records instead of END records
 - Select... Chain menu now includes rollovers for chain IDs that appear in more than one model, allowing selection of a chain within a specific model or (as before) all models
 - Select... Structure menu now includes nucleic acid and protein
 - Actions... Atoms/Bonds now has three options for displaying backbone only: chain trace, full, and minimal
 - Actions... Focus adjusts the view as before, but then sets the center of rotation to track the center of view (rather than setting a fixed center based on the specified atoms)
 - changes in preferences:
 
- a preferences file can be specified at startup with --preferences
 - the preferences file location is reported but can no longer be changed from within the Preferences dialog
 - the preferences file can be designated read-only
 - settings in each tab of the Viewing tool can be explicitly saved to and restored from the preferences file
 - Collaboratory and Image Setup sections removed
 - VRex row stereo mode removed
 - camera mode and stereo parameters are saved in sessions
 - improved session merging (opening a session in the presence of pre-existing models)
 - mouse mode for pop-up Chimera menu implemented (see the Mouse preferences)
 - on Windows, rolling the mouse scroll wheel is another way to scale
 - added 64-bit Linux AMD64/EMT64 production release
 - added Mac OS X Aqua snapshot release (for users who need stereo, full-window antialiasing, and/or background transparency)
 - added orthographic support to export formats
 - export labels to X3D and POV-Ray files
 New Tools:
- Fit Map in Map (Volume Data) — locally optimize the overlap of two density maps
 Tool Changes:
- Add Charge (Structure Editing) — updated to recognize v3.0 PDB naming conventions
 - AddH (Structure Editing) —
 
- updated to give the hydrogens v3.0 PDB names if input is v3.0
 - includes peptide terminus recognition with OXT addition as needed
 - Camera (Viewing Controls) —
 
- DTI side-by-side mode added for stereo viewing with technology from Dimension Technologies Inc.
 - allows control over additional parameters affecting stereo and the amount of perspective
 - Collaboratory removed (use version 1.2309 for this tool)
 - DelPhiController (Surface/Binding Analysis, Volume Data) —
 
- can Browse to the DelPhi executable location
 - improved handling of pathnames and retention of parameter settings within a Chimera session
 - DelPhiViewer portion removed; use Electrostatic Surface Coloring and/or Volume Viewer instead
 - Dock Prep (Structure Editing) —
 
- peptide terminus recognition moved out of this tool and into AddH
 - option to delete ions added
 - EnsembleTile (Structure Comparison, MD/Ensemble Analysis) — Border scale parameter added to control spacing
 - Fit Model in Map (Volume Data) — more detailed information sent to the Reply Log
 - MatchMaker (Structure Comparison) — nucleic acid residues lacking C4' atoms are paired using P atoms instead
 - MD Movie (MD/Ensemble Analysis) —
 
- GROMACS support added
 - for PDB inputs only, coordinates supplied for a frame may now include just the atoms that moved relative to the previous frame
 - added option to ignore hydrogens when calculating RMSD values
 - specifying end frame as "pipe" allows reading piped trajectories
 - movie recording default image format PPM, frames can be supersampled or raytraced, movie can be encoded as a "round trip"
 - Measure Volume and Area (Surface/Binding Analysis, Volume Data) — can update measurements automatically as a surface changes (excluding molecular surfaces)
 - Morph Conformations (Structure Comparison) — improved to handle structures with different numbering, different numbers of residues, and even different sequences
 - Movie Recorder (Utilities) —
 
- default image format changed to PPM (faster to save than PNG)
 - image frames can be supersampled or raytraced
 - movie can be encoded as a "round trip" (A→B and then in reverse, B→A)
 - Multalign Viewer (Structure Comparison) —
 
- Find Subsequence, Find PROSITE Pattern, and Alignment Annotations moved from Tools menu to Edit menu
 - a tree (Newick format) can be read and displayed alongside the corresponding sequence alignment
 - sequences from structures open in Chimera can be added to an alignment
 - Nucleotides (Depiction) — updated to recognize v3.0 PDB naming conventions
 - Render by Attribute (Depiction, Structure Analysis) — attribute values can be saved to a file (File... Save Attributes)
 - Shininess Control (Viewing Controls) — made a subpart of the Lighting tool
 - Side View (Viewing Controls) —
 
- double-clicking the eye position brings up a menu for changing the camera mode (mono and stereo options)
 - top view interface added for interactive adjustment of stereo parameters and perspective
 - Surface Color (Volume Data) — allows coloring by volume data gradient norm
 - ViewDock (Surface/Binding Analysis) —
 
- starts up with the first ligand displayed (rather than all)
 - descriptors such as DOCK scores are now assigned as attributes (can be used for coloring, selection, etc.)
 - which columns to display can be specified in a text file
 New Commands:
- bondzone — make zoning tools use points along bonds
 - namesel — name and save the current selection
 - ribscale — set ribbon scaling (named set of secondary-structure-specific dimensions)
 - windowsize — set graphics window dimensions
 Command Changes:
- in specifications by attribute, a color can be indicated with a comma-separated list of component values (red, green, blue, and optionally alpha, in that order) as well as by name
 - ~color — requires target specifiers (r for ribbon, etc.) to be comma-separated (this was already the case for color)
 - copy — raytracing keywords added
 - focus — adjusts the view as before, but then sets the center of rotation to track the center of view (rather than setting a fixed center based on the specified atoms)
 - match — allows use of <4 atom pairs (although transformations are not unique for 1-2 pairs)
 - movie — default image format PPM, frames can be supersampled or raytraced, movie can be encoded as a "round trip"
 - open — noprefs keyword added to bypass the New Molecules preferences when a structure is opened (prevents inconsistent behavior of scripts potentially caused by the different preferences settings of different users)
 - rmsd — allows use of <4 atom pairs
 - savepos — includes positions of any per-model clipping planes
 Documentation Changes:
(other than updates/additions reflecting the changes above)
- DelPhiController documentation expanded significantly to explain parameters and link to DelPhi documentation at Honig site
 - Introduction to PDB Format updated and converted from PDF to HTML
 Major Bugs Fixed:
- molecule coordinates can be saved relative to a volume display (or other non-molecule model)
 - cross-eye stereo mode fixed
 - corrected stereo image saving with the "same as screen" option when the graphics window is in cross-eye or wall-eye mode
 - corrected label position/scale in saved images smaller than the current display (standard and 2D labels)
 - accept Sweet2 generated PDB files
 - export transparency correctly to POV-Ray files
 - don't export undisplayed models
 chimera --sendnow always returns even if a new chimera is started