At 05:01 PM 3/5/97 GMT, John R. Nash wrote:
(this message cc:'d to the MOTM page creator as well as sent to ChemWeb)
Trevor Gilson <T.R.Gilson@soton.ac.UK> said:
The latest motm goes round a bit too fast with chime (is this clock-dependent?). Must be close to the epilepsy-inducing rep rate.
I agree that the molecule spins too quickly, and I think I may know why. When Chime reached version 1.0, there was a change in the spinrate parameter, such that "normal" spin rates with older chime versions now spun a lot faster. The parameter is now "degrees per second," with a 30 degree spin of the y axis the default. See http://www.mdli.com/chemscape/chime/chimehelp.html#Dev2 for details. FYI, the current MOTM page is set with SpinY=360, or one rotation per second. When I upgraded to 1.0, I had to slow down all of my overly hyperactive molecules.... (shameless plug: http://www.chem.wisc.edu/~casey/research.html)
John is correct here, Chime 1.0 was fixed so that it correctly took the spinX/Y/Z parameter into account and tried to correctly 'match' the requested degrees of rotation to watch actually occurred. Unfortunately one side-effect of this bug fix results in 'overly hyperactive' chimed structures. Chime's rotations should *not* be dependent on the clock speed of the computer. (It is possible that a slower computer would rotate a 'difficult' structure SLOWER, but never a fast computer rotating faster (then requested)). There are several factors that effect rotation: spinFPS: Frames per second that chime will try to display/apply the requested rotation parameters spinX, spinY, spinZ: The degrees per second of rotation for each axis. The degrees of rotation for each 'frame' of the rotation is computed like this: frameX = spinX/spinFPS frameY = spinY/spinFPS frameZ = spinZ/spinFPS For each 'frame' that Chime moves structures the above frameX/Y/Z amount. Chime (as of 1.0) will now try it's best to achieve the requested frame rate, it should never go *faster* then the requested frame rate. The max FPS that can be *achieved* on different machines varies, but in practice no Windows 3.1/95 machine can get more that 17 frames per second because of limitations of the timer on this platform. The SGI should be able to get up to 60 FPS, and a fast PowerMac can probably get near 60 as well. The 'move' command in Chime 1.0's scripting language can be used for a more precise control of rotation/zooms/translates. The command allows the other to specify the amount a 'move' will be 'sped up' on a users machine to compensate for a slower machine. Eric's site has some good examples, and some docs, on the move command. Hope that all made sense... -tim
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-john nash
-==-John R. Nash-==-nash@chem.wisc.edu-==-UW-Madison Chem. Dept-==- --- "When in doubt, roll!" ---
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