Making Movies

Chimera includes the following approaches for capturing image frames and assembling them into a movie file:

The image frames can be rendered directly by Chimera or created by raytracing with POV-Ray. See below for information on developing movie content and troubleshooting problems in PowerPoint. See also: tips on preparing images

Movie Content

During recording, structures can be manipulated interactively and commands entered. However, for reproducibility and smoother results, often a Chimera command file (script) will be used instead. The commands listed below are especially useful for scripting continuous motion and/or specifying movie content. See also: movie script examples, video mini-examples for individual commands

2dlabels - display 2D labels, which can be faded in or out over a specified number of frames
background - set background color(s) or image
clip - move global clipping planes
cofr - change the center of rotation
coordset - play through frames of a trajectory
fly - smoothly traverse a series of positions previously saved with savepos
freeze - stop all motion
mclip - control per-model clipping
move - translate models
movie - capture image frames and assemble them into a movie file
perframe - specify commands to be executed at each display frame
play - script various complex motions
reset - interpolate from the current position to one previously saved with savepos
rock - rotate models back and forth (oscillate)
roll - rotate models
rotation - rotate bonds (adjust torsions)
savepos - save and name a “position” (model transformations, scale, etc.)
scale - scale the view
scene - save and restore “scenes” (positions plus styles, colors, labels, etc.)
section - move the clipping planes in parallel
select - activate/deactivate models for motion
set - set visual effects, make models rotate about individual centers, echo command-file lines as they are executed
thickness - move the clipping planes in opposite directions
transparency - make atoms/bonds, ribbons, and surfaces transparent
turn - rotate models
vop morph - morph (interpolate) between two or more volume data sets
vseries - display an ordered sequence of volume data sets
wait - suspend command processing for a specified number of frames or until motion has stopped
windowsize - set the dimensions of the graphics window

In addition, the commands sleep and pause are useful for introducing pauses during live script execution, but not in movies, as no new frames are drawn during such pauses.

The graphics window should be adjusted to the desired dimensions before recording, for example with the command windowsize. Using a small and standard size (320 x 240, 640 x 480, or 800 x 600 pixels) may solve some playback problems. On certain platforms, other windows should not overlap the Chimera graphics window during recording (details...).

Frame Rate and Movie Speed

In Chimera, the target or intended graphics frame rate is 60 fps (default). The actual frame rate may be lower depending on computer performance and what is being displayed. Recording generally slows the process further; however, the frame rate of the resulting movie is controlled independently with an encoding parameter (default 25 fps). Thus, movie playback may be faster or slower than the original process in Chimera.

The command set maxFrameRate can be used to set the Chimera target rate to match the movie frame rate, so that “live” execution of a script will show the movie contents at the same speed as the resulting movie (or at least, as similar a speed as possible given performance limitations). The Animation tool sets the target rate to 25 fps temporarily during timeline playback. The accelerator rt (command ac rt) allows monitoring the actual frame rate.

Movie Command File Examples

Simply opening a command file in Chimera will execute its contents. Command script execution can be aborted by pressing the Esc (escape) key, or paused/resumed (with no new frames being drawn during the pause) by pressing Shift-Esc.

The online movie-making tutorials (2009, 2012) and the Chimera Animation Gallery contain additional examples. See also: video mini-examples for individual commands

Problems in PowerPoint

On Windows, some Chimera-generated movies cannot be inserted into PowerPoint presentations, or can be inserted but will not play.

Using a small and standard frame size (320 x 240, 640 x 480, or 800 x 600 pixels) may solve some playback problems. Before recording, the Chimera window can be set to specific dimensions using the command windowsize.

In PowerPoint 2000, only the Chimera MPEG-1 format works, but the quality is very low. Using PowerPoint 2003 or newer is recommended. With PowerPoint 2003 on Windows, the Chimera AVI MSMPEG-4v2 format is recommended. Although a movie in this format can be inserted into a presentation, it may play as a black rectangle. To remedy this, try reducing the video acceleration in Windows Media Player (instructions are for Media Player 10.0, but should be similar for other versions):

  1. start Windows Media Player (for example, by right-clicking a movie icon and choosing Play with Media Player)
  2. right-click the top bar of the Windows Media Player window and choose menu entry Tools / Options...
  3. click the Performance tab in the Options dialog
  4. click the Advanced... button in the Video Acceleration panel
  5. turn off Use video mixing renderer
After PowerPoint 2003 has been restarted, the movie should play correctly within the presentation. We have not tested movie playing in PowerPoint 2007. A more drastic alternative to the last two steps above is to move the slider in the Video Acceleration panel in the Performance tab to None.

Video acceleration in Media Player is not the only potential source of trouble. If the problem persists, see the Microsoft page on troubleshooting movies in PowerPoint.

UCSF Computer Graphics Laboratory / May 2015