Factorio Forums

TL;DR

Be able to make custom factories.

What ?

Like a blueprint but it fits into a single factory block and is scaled by its size.
It's actually a seperate map because it's located inside a factory, you define its size 10x10, 15x20, whatever you need
Then you build a factory layout using the same tools. Accept what ever inputs you need and output what you want all based on the existing rules
Then you place this custom factory at the size you have available. It's part cost, speed, power pollution scale to the size you make the factory

Why ?

Space is limited cause you made a mess but you want a certain product nearby.
Not OP, if you make a factory on a 10x10 grid then place down a 10x10 sized custom factory, there is no difference cause it would have used the same space anyway. But if you only have room for 8x9 then you can place down what you need and scale production based on the size difference.

https://mods.factorio.com/mods/MagmaMcFry/Factorissimo2

Not quite the same, since it isnt as abstracted and has the size shift, but almost the same idea.

Yes, very similar idea.