Thanks for the repy, but that doesn't work for me -- no matter where I am on the timeline, any change I make to the volumetric cloud changes the setting at frame 0 -- with no key frame added at the frame I'm at on either the master or the instance.  Am I nuts?  Are you really producing animated volumetric clouds?  Thanks!  (I've got 5.1 Pro installed, on Mac OSX 10.3, just in case.)

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