Cool, thanks. The main motion works for me (FF 2, linux, on a eeePC 900MHz), except for black circles that appear and disappear near the center, in 3 locations (only one is visible at a time, and sometimes none are).

Here's results from your test that gives performance figures (http://animatedengines.com/svg/testp.xhtml), running with several tabs open:

    fps              10      20      30      50
    Average overrun  -0.091  30.212  46.919  59.707

(I let it update a few times to settle down before pasting the figures, so they represent an average of the "average overrun").

Maybe it doesn't matter so much if the fps is slow for more complex engines? If the change between updates is small enough, it will look pretty smooth. Is it important to be able to make the machine rotate fast? I mean, it looks cool, but does the viewer gain greater understanding from this? (I'm not being rhetorical - I really don't know. Maybe it gives an overall feel for the engine's operation).

Sorry, I don't have any experience with JS animation to address the issues you mention. Some people here probably do though - or why not ask on http://stackoverflow.com ? It's often excellent for clear technical questions.

The SVG animation looks much nicer. It works well in Chrome 3.0.193.0 in Windows XP.

works very smooth with FF 3.0.10 on ubuntu.

I've pointed my son at it and he's been talking engines to me all day long :)

Thank you!