Hi Daniel, You might consider writing your script with a series of "reset" commands rather than "fly" -- the difference is that fly considers the trajectory to be taken after the next position, so that the whole thing looks smoother. If A,B,C,D are saved positions, schematically: fly A -> B -> C -> D where the approach to C is already being considered before arriving at B, versus reset -> A; wait reset -> B; wait ... where each reset command can specify number of frames (does not have to be instantaneous) The wait commands prevent the movement commands from overlapping execution. Shift-Esc will pause the script after the current command is done. If it is in the middle of a reset to C, it will go that far and then stop at C. Then it can be resumed with another Shift-Esc. That is not as precise as what you had asked about (instantaneously pausing), but more precise than after an entire fly command finishes. A demo is inherently a series of commands, and doesn't allow pausing in the middle of a command, so "reset" is probably also needed in that case. It is the only way I can think of in Chimera where you can just press a button to go back to a previous state. Easy for the user, but... Demo issues: - you would need to start the demo by opening a session with your saved positions, unless you know how to generate those positions by a series of commands - the "go back" feature automatically takes care of positions, but the demo creator is responsible for figuring out any other commands needed to revert to the previous state (any displaying/undisplaying, changing colors, styles). It can be more confusing than it sounds! You can see the "guts" of a demo by choosing it from the Tools... Demos menu (starting to play it back) but then choosing "File... Open in Editor" from the demo panel. Elaine ----- Elaine C. Meng, Ph.D. meng@cgl.ucsf.edu UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco http://www.cgl.ucsf.edu/home/meng/index.html On Aug 21, 2009, at 6:25 PM, Tom Goddard wrote:
Hi Daniel,
The demo capability in Chimera is designed to do what you want including rewind.
http://www.cgl.ucsf.edu/chimera/docs/ContributedSoftware/demos/ demos.html
It doesn't allow pausing in the middle of a motion -- only between panels (maybe between individual commands associated with a panel - not sure). But the idea is that the duration of motion in each panel would be short. We haven't made many demos and this tool may be pretty rough around the edges.
The trouble with the pause command or Shift-Escape to pause/resume a script is that the fly command returns immediately after you invoke it. It sets up playing the motion which then happens after the command returns. Normally that motion could be halted with the command "freeze". This works with other motion commands "reset", "roll", "move", and it should work with "fly" but doesn't yet work for "fly". In any case, it simply terminates the motion and there is no way to restart it, so that won't do what you want. There is no mechanism to pause the playback in these motion commands, though maybe "pause" and the Shift-Escape key should be made to do that. Currently those mechanisms just block running of additional commands I believe.
I wonder whether pause/resume would be adequate for teaching purposes. Seems very likely to me that you will need rewind. By the time a student asks a question the motion is already past the relevant section. We don't have any rewind capability in the motion commands or in general scripts, only the demo tool, and even there I think can be tricky to make it work.
Tom
-------- Original Message -------- Subject: [Chimera-users] pause during a fly-by? From: Daniel Gurnon To: chimera-users@cgl.ucsf.edu Date: 8/21/09 5:52 PM
Hi all, I've been considering ways to use Chimera in the classes I teach, and I love the potential of the "fly"command for smoothly navigating between preset positions. But is it possible to pause in mid-flight? The pause command hasn't worked for me here. What I'm really looking for is a way to automate some features of a presentation (e.g., the camera position) while retaining interactivity. Making a quicktime movie is less than ideal, because although I could pause the movie if a question is asked, I couldn't, for example, use a clipping plane to strip away a surface to show an underlying backbone, and then smoothly resume the camera flight. Perhaps I should consider making a demo instead, where pauses are built in?
Thanks Dan
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Daniel Gurnon, Ph. D. Assistant Professor of Chemistry DePauw University Greencastle, IN 46135
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