There is probably a few ways to go about it. Keep in mind you can also key an object to switch layers to make it appear or disappear. So, for example, you could have all the floors in place and timed to appear just as a (repeating) animated floor gets there and disappears.
You can cut, paste, duplicate, and edit keys in the IPO editor. So you could make the floor animation going to top floor, duplicate the keys to make it do it 20 times, then edit the keys to make it stop (and disappear) at the right place and time… timed with the “real” floors appearing.
Knowing all the tools available helps greatly, but it usually takes some thought to figure out the quickest or easiest way to go about something like this. The method above is off the top of my head. I wouldn’t doubt there’s a better way.
I tend to figure out the “best” way after I find myself in some ridiculous hour-long repetitive task that could have been accomplished with a few clicks if I had better thought it through before I plowed in. :rolleyes:
Btw Check the Blender Manual in my sig to find your way around the IPO editor. It’s often quicker ,easier, and more precise to work in there instead of moving and keyframing objects in the 3D view, especially when editing an animation already keyed.
*** Edit: “you could make the floor animation going to top floor, duplicate the keys to make it do it 20 times, then edit the keys to make it stop (and disappear) at the right place and time… timed with the “real” floors appearing” …
You don’t even have to edit the animation to stop at each floor, just edit when it jumps to a different layer (disappear), or maybe just jump to bottom… all in the timing… see what I mean about thinking it through?
Links from the manual: