How are phase changes simulated?

[CodingKitteh]

First off, I love (an understatement) this game. I usually don't buy early access games but I bought this one. The thermodynamic and systems building combined with survival aspects of the game really caught my interest and sucked me in.

Now, I have been experimenting in debug mode to learn about the game's internal mechanics. I understand the environment in the game uses simulated thermodynamics, meaning it's not 100% true of real world dynamics. However, I discovered a weird part about the thermodynamic aspects of the game: phase changes.

1. Sublimation (Solids-> Gas) and Deposition (Gas -> Solid) is not simulated (...yet, I hope!)
2. Heat of Fusion/Vaporization/Sublimation doesn't seem to be used in phase change calculations
3. In-game matter in a vacuum does not undergo phase change (they do in real world)

Furthermore, I took screenshots where the thermodynamics stopped making sense.

1. Superheated Water
   1. Observations:
      1. The water is 4700°C, higher than the temperature of melting Abyssalite (MP: 3421°C) yet the Abyssalite insulating tile is not melting.
      2. The water is also under a vacuum yet does not vaporize (phase change: liquid -> gas) even when the water is way beyond 100°C to boil
2. Superheated Ice
   1. Observations:
      1. The ice is 726°C inside a vacuum. There are two things here:
         1. The ice will sublime even at lower temperatures below 0°C due to low pressure (phase diagram of water)
         2. The ice itself has enough internal energy to undergo two phase changes (solid -> liquid, then liquid -> gas) @ 726°C but doesn't. Although a more realistic interpretation would be that the ice would've long sublimed into steam (phase diagram)

Conclusions:

1. I hope to discuss this topic to inspire more realism into the game. While the game itself is already complicated, certain thermodynamic aspects just doesn't make sense (or is completely left out). Perhaps the universe in ONI operates with a completely different set of physical laws
2. Devs please review!!!
3. Other posters who also observed weird thermodynamics should also pitch in

Chaotic Dreamland.sav

[Masterpintsman]

I posted a suggestion to add phase change enthalpy a while ago, so we would have incremental melting of ice and whatnot.

A short answer to your question from the title

Quote

How are phase changes simulated?

is: Currently very badly, sadly. I hope this will be fixed at some point, preferably sooner than later.

[Kasuha]

The major obstacle with the ONI physics is the one element per tile restriction. It makes many things awkward but I'm pretty sure we're going to stay with it.

I agree that your superheated water/ice are probably bugs in the simulation. They should undergo the phase change, I see no reason why they shouldn't. I noticed in many cases that gases wouldn't liquefy even when below their dew point, sometimes way below it. It may be similar issue.

The heating of the abyssalite tile is another story. The water is hot, but the abyssalite has so low heat transfer that it's not heating up. And it can only break after the tile itself reached certain temperature. The tile as the basic building block of ONI physics does not really allow greater level of detail.

 

 

[LeadfootSlim]

I want to know more about - or possibly see more of - phase changes within duct work. Frozen pipes? Boiling pipes? Gases condensing in air ducts? There's a lot of room for intrigue here!

[Kasuha]

1 hour ago, LeadfootSlim said:

I want to know more about - or possibly see more of - phase changes within duct work. Frozen pipes? Boiling pipes? Gases condensing in air ducts? There's a lot of room for intrigue here!

Phase change inside a pipe will break the pipe.

[LeadfootSlim]

7 hours ago, Kasuha said:

Phase change inside a pipe will break the pipe.

Is this for freezing water only, or will boiling water and condensing gas also freeze their respective pipes?

[Risu]

3 minutes ago, LeadfootSlim said:

Is this for freezing water only, or will boiling water and condensing gas also freeze their respective pipes?

Phase change inside a pipe will break the pipe.
 

[LeadfootSlim]

Just now, Risu said:

Phase change inside a pipe will break the pipe.
 

...well, alright, then. In that case, i'll just have to sit back and cross my fingers on better implementation of phase changes eventually.

[Kasuha]

19 minutes ago, LeadfootSlim said:

...well, alright, then. In that case, i'll just have to sit back and cross my fingers on better implementation of phase changes eventually.

You can do phase changes in open space. Hydrogen at suitable temperature is a good medium for that, you can either pump it to the space filled with whatever medium you want to undergo phase change, or run it through gas pipes in such room, First is faster, second saves you separation. 

Evaporating of liquids with boiling temperature 100 C or above is challenging, can be done in a cheaty way with liquid tepidizer.