Good size for a room?

[monereau]

Hello! I like to make all the rooms of my workshop 10 m x 10 m like this :

https://www.noelshack.com/2019-46-4-1573761834-w4.png

I do this in prevision of the moment where I'll have to buy more machines to produce more. Because I can buy more machines in the same room and thus I don't need to create an another room elsewhere in my factory. So all the machines of the same type stay in the same room at the end. Plus, large rooms have less obstruction

But it seem that it's not the optimal way to build a factory in this game. So my questions are :
How do you build a good factory? With what size for a room?

How do I plan for the future when my factory grow?

Should the size of my room have to be random as long as I can put everything I want in this room even if it's tight at the end?

Do worker obstruction have importance?

Thank you for your time ! :-)

[Saint Landwalker]

Worker obstruction absolutely matters. In small doses it's not that big a deal, but large amounts of obstruction can really mess up your efficiency and flow. I try to avoid going too over the top with obstruction. Even so, you can fit a lot of things in a room without running into a major obstruction problem.

As far as room sizes, the limit before you get the -25 Mood penalty for Large rooms is 400 tiles, and the limit before you get the -50 Mood penalty for Huge rooms is 600 tiles. This equates to a 10.5×10.5m square room, or a 5.5×20.5m "long room," etc. (Note that because of how the game measures wall length, all of the game's measurements are 0.5m too long or too short, depending on whether you want it to convey "inner wall to inner wall" distance or "outer wall to outer wall" distance.) Early in the game, when you don't have a lot of good Decor items, I'd suggest trying to keep most rooms within the 400-tile "normal" room cap.

Regarding "planning for the future," don't worry too much about that. Make a factory that works well for your current situation. As long as you have a good economic foundation, you can always remodel down the road without too much grief.

The biggest cost of remodeling a factory is in new construction (i.e. constructing new chunks of building where there previously was no building). Deleting and building interior walls where the building "shell" already exists is pretty cheap, so don't worry about building rooms now to accommodate your plans later—you'll always be able to just knock down walls and build new ones to rearrange your existing building space.

In my experience, you usually don't need a full 400-tile room dedicated to a single type of workstation (there might be a couple of exceptions depending on how you focus things). You're almost never, for example, going to need an entire 400-tile room of circular saws, so don't be afraid to consolidate machines that frequently "go together" (like circular saws and stick saws, or sheet rollers and form press machines).