In Blender 2.8, how to make an animation with different objects appear at different keyframes I am new to blender. I have a question related to the animation in 2.8. Actually, I have several obj files, and I import them to get multiple objects.

For example, I have 30 objects imported from my given obj files. Now, I want to make an animation, where each frame shows one object. For example, at keyframe 1, I show my object 1 and hide other objects, and at keyframe 2, I show my object 2 and hide others including object 1, etc.

I tried several ways, including shape keys, but it does not work for me, since my objects may have different vertices (unable to join). Also, if I set a different keyframe for a different object, they are not on the same channel. Thus, I can not show a video in this way as well.

My simulation is something like the liquid moving status, but I am only allowed to combine such objects into an animation, not directly use the blender to get a liquid effect. So my question is, if I have many objects, how can I make an animation, and show one object at each frame and hide others? Thank you so much!
If I understand your question correctly you're simply trying to switch objects visible for one frame, then off again to be replaced by the next object at the next frame and so on...

The slo-mo video below shows masks 10, 11, &amp; 12 being visually switched in and out at frames 10, 11 &amp; 12 respectively.  This is done in the Outliner at right.  The eye icon is simply keyframed on or off by hovering over the icon, clicking so it's on or off, then pressing  "i" key. (insert keyframe)  If you make a mistake, hover on it again and press  "ALT-i"  to remove the keyframe, or CTL-Z.

Note - when not rendering  in OpenGL, the camera icons would need to be switched and keyframed the same way.