Conditions for looping particles may be possible

Hi.

I have seen some tutorials where they talk about looping particles system, and they generally show particle systems emitted from a plane where the emitted particles pass from side to side throughout the camera:

But what happens when the particles are emitted from multiple directions?:
Particles Looping-Cube-Multi Direction-Not Working.blend (134.6 KB)

I would like to know the rules or conditions that a particle system must meet in order for an animation looping to be possible.

I would like to know if it is possible to loop the previous example, or for example, dust particles floating in multiple directions throughout the camera. I suppose this has to do with particles appearing or disappearing from the camera, but I can’t deduce the logic behind it.

Edit 1:
I forgot to mention that I need particles not to suddenly appear/disappear from the camera for the duration of the animation. For the type of animation I need, it would be annoying to see particles born/dying sometime during the loop. That is why I think that the logic to achieve it could have to with the time/moment until the last particle disappears from the camera. But I’m not sure.

Edit 2:
Apparently this depends on Physics > integration > Timestep. For the example above, apparently with a large enough value (0.250) makes the simulation seamless. But this makes the speed of the particles faster. I suppose there will be a formula for how looping can be calculated with the desired particle velocity.

i dont know if it help your case but there’s this tutorial from Midge https://youtu.be/I8iIgdz9VAc?t=2940

Thanks, I’m going to try to follow that tutorial. Earlier I forgot to mention that I need particles not to suddenly appear/disappear from the camera for the duration of the animation. For the type of animation I need, it would be annoying to see particles born/dying sometime during the loop. That is why I think that the logic to achieve it could have to with the time/moment until the last particle disappears from the camera. But I’m not sure.

i did this 2 months ago it’s a looped flip simulation ( i looped the particles before meshing ) and we don’t see the particles appear/disappear. I used the technique from Midge
https://www.youtube.com/watch?v=ZrpY9KJ2JGU ( right click on the video : loop video )