Hello, If anyone knows, please chime in;

What happens when a factory is destroyed by biters?
(I assume everything in the factory is lost;)

What happens if you are in a Factory and it is destroyed?
(Do you die or get ejected from the factory or become perpetually lost in the factory dimension?)

Can someone pickup a Factory while you are in it?
(If they can, what happens to you while in the factory?)
I read the FAQs but couldn't find much on factory destruction other than copy/cut doesn't move the current factory layout.

When a factory building is destroyed by damage, the interior becomes inaccessible but will not be destroyed too. Players inside will not be ejected to outside, and they can still leave the factory building (but not reenter, of course). The exit point is at the factory building's last valid build location.

The same goes for picking up factory buildings: if you're in a factory building while somebody else picks it up, you can still move around in the factory building. If you leave the building while it is picked up, you will appear at the factory building's last valid build location. If you stay in the factory building until it is replaced, you will be able to exit the factory building at its new location.

Thanks MagmaMcFry!

So, I assume when a factory is destroyed, the factory interior space still exists, but is no longer accessible; is there a way to rebuild a factory that was destroyed? (Reconnect the interior space with the factory item).

I think I saw there is a command "/give-lost-factory-buildings" that will cause destroyed factories to appear in your inventory, but is there a way without the command console? (Like building a new factory and some how assigning it to an existing space that is not attached to another factory).

Anyways, thanks for your detailed answer above, that's what I was wanting to know before really diving it, this mod looks awesome!

There is no way to reclaim interiors of destroyed factories without using this command.

Is there garbage clean up of the destroyed factory (IE destruction of platform) to help reduce size and UPS load after player exits the destroyed factory ?

No, because a) I need to keep the contents for the command to work and b) other mods might own managed entities in factory buildings which could cause errors when they're destroyed. As for UPS, I wouldn't worry about that. Non-built factory buildings don't cost significant amounts of UPS, they're only visited by Factorissimo's code once per second to gather up pollution, and once power in the building runs out, Factorio is sufficiently optimized to deactivate the interior chunks anyway.

ohh okay i thought the interior chunks would constantly stay active tying up ticks and ups. Well then okay thats cool to know thank you for the answer. What brought about the answer, was that i've built like over 50+ nested buildings in one mega tier 3 building, multiple tier 2's, and within tier 2s i have multiple tier 1 buildings. Default settings, and the ups just crushed my desktop but then again the map was like 90mb and fully loaded with over 50k enemies too. Lol.