Pressure causes liquefaction

[tasauge]

Hello,

I have a suggestion. Right now, pressure does nothing to liquids and gas, but in real life overpressurizing a gas cause it to liquefy, and underpressurizing a liquid cause it to evaporate.

Why not add this in ONI?

[Sasza22]

The reason is that currently the phase change temperatures are set in stone. If we make pressure modify those it will be much harder to track. Also in real life going low on oxygen doesn`t lower the pressure. I imagine that would cause a lot of trouble (water tank evaporating when you don`t produce onough oxygen).

To an extent we have this mechanic through space. Liquids get drained when exposed to space so they evaporate into vacuum.

[Morse]

The correct simulation of the phase transition is almost impossible. There are no simple equations, the process is chaotic (in a mathematical sense, so maybe the correct word would be "stochastic"). Also, the correct implementation of a phase diagram will require the correct implementation of such things as a triple point, a critical point, a supercritical fluid state and a bunch of others. And I don't even think that the simulation will work with the level of discretization implemented in the game. What you're asking for may be simply mathematically impossible.

Although I agree that this simplification adds some weird things, like liquid CO2. Liquid CO2 cannot exist in a pressure below 5 ATM, let alone in near-vacuum conditions.

[he77789]

You mean adiabatic heating/cooling?

[D.L.S.]

On 18.08.2018 at 8:06 PM, Sasza22 said:

 Also in real life going low on oxygen doesn`t lower the pressure.

Ever heard about titanium filament based vacuum pump - it "destroy" oxygen oxidizing hot titanium filament - turn titanium into titanium oxide bounding oxygen, it really creating vacuum by consuming oxygen. Basically same thing doing dupes in game - consuming oxygen leaving only small amount of co2 which pressure not enough to compensate oxygen losses leading to pressure drop almost to vacuum, this is broken design by itself, you cant inhale 100g of o2 and exhale only 2g of co2, even not counting added carbon, where the rest 98g gone(?).

 

On 20.08.2018 at 11:45 AM, Morse said:

The correct simulation of the phase transition is almost impossible.

Easy to say impossible. Noone ask full simulation, but adding at least one curve for boiling point@pressure of some "ideal" liquid and use it for all liquids in game can be done. Get rid of critical state and stand that after some pressure each gas will be always liquid, or after some temperature liquid will be always gas, need choose one of this 2. Triple point - can use melting point which already in game, below this temperature liquid/gas for this substance wont exist, only solid state. Add rule if liquid turning into gas it cools down liquid for a some amount(pull out heat energy), if gas condensing it heat left gas for some amount of heat energy(add heat energy to left gas). Is it impossible to make?

All this work in small game called "powder toy" and there they dealing with simulating particles(many particles), not with huge tiles filled with gas/liquid/solid like in ONI, it is not much accurate but still give great impression that physic laws working as expected.