Object move, when animating rotation only

Greetings, i have issue with animating in unity… I have 54 elevator carts, moving up and down. I could animate 90% of them without problem, but at rest of them, animation start acting weird, adding some extra unwanted position.

Animation steps was simple:

1. selecting object
2. click on 1s on animation tab
3. move cart little higher and little rotate (actually move and rotate on position of another one)
4. Result → object moves further higher and drops back to position i made. Like a car bump on road
5. When i continue to animate another cart in line, position of this object goes more higher. Third and fourth continuously even more, like they are synced with previous

When i create key at 1s with rotation only, unity automaticaly add some weird moving into anim.
I tried to figure out, messing with Auto, Free Smooth, Flat, Broken and both tangent, but nothing works, just created crazier move around scene.

Edit: → 1

So you’re animating each one of these carts by hand and creating the illusion of a moving chain, when in fact each member of the chain is actually moving to take its neighbor’s position, then snaps back into place. Correct?

Honestly, I’m not sure why you’re seeing the behavior your witnessing at the top of the chain. If you’ve checked each curve of your animation to ensure no obvious mistakes are present, I don’t know what to suggest. Anyone else, feel free to chime in.

I would approach this situation differently, but only because I’m weird and I prefer functional, scripted animations. I’d have each element (cart) scripted such that they actually move all the way around the track. They travel N distance in ABC direction, then RotateAround 180 degrees at the center point of the circle of the imaginary pully at the top of the track. Then they do the opposite, moving -N distance in -ABC direction, then RotateAround the other pully. Doesn’t solve the original problem, but it would bypass it and give you a “real working” chain.

Open your animation window and switch to Curves view (button next to Dope Sheet), then click on the offending carts and zoom in on the curve to see where is the abnormal path. Perhaps you can adjust the curve manually.