Condensation!

[Taverius]

I tried using a density and externaltemp curve to get h20 condensation to work right, but its essentially impossible for a human to tune two curves at once to make it work right at every point.

A custom bit of code that follows the water phase diagram would be useful for 99% of non-SRB 'smoke'.

[eggrobin]

Perhaps not code ad-hoc for H₂O, but the ability to select from a range of smoke compositions, these being defined in a separate cfg containing the phase diagram etc. would make it easier to make sensible smoke without replicating lots of information.

[Taverius]

Sure, being able to input the definition of the condensation curve of a phase diagram would be great.

Still, outside of real fuels and KSPi (and how that would work given the in-flight propellant switch ive no idea) water covers pretty much everything that actually needs a phase-diagram based solution.

[eggrobin]

Well, there's no way to have this phase diagram without having lots of data (we're not doing computational chemistry). Hardcoding large splines is silly, so we should load them. At that point we can support arbitrary phase diagrams, so let's do that :-p

[eggrobin]

CO₂ exhaust also seems relevant, e.g., it freezes on Titan.