Atmosphere Density And Height Control - A Doable Simulation

Rafs

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#1
Hey!

A few weeks ago I had this idea on discord and asked some people about it, and even some devs present thought it could be doable.

The idea is really simple:

Have some blocks "upwards push" increase or decrease depending on the height data of the tech (the one the altimeter shows).


That's it, just it. Yet it would have a great, very welcoming impact into the game.

Imagine being able to control height by adjusting the power of heli propellers (maybe even upwards pushing thrusters). Antigravity would have the purpose of nullifying that variable, if one wanted to.

Planes wouldn't fly up indefinitely, helis would be easier to tune as said, hovers wouldn't be affected (they repell ground, not air).

This also enables the addition of passive "upwards pushing" blocks such as floater tanks.
These tanks would range from low density gases inside (maybe even flamable) to expensive but safe and powerful vacuum tanks. This enables balloon like techs, a cheap yet limited kind of antigrav (limited by how height would affect it).

If the idea wasn't clear, it's just that height, which is a thing in the code, would have a weight on "upwards push power" for blocks. A simple code thing. It's not about air density for drag effects or anything, just height control/responsiveness.

What do you people think?
 
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WhitePaw2002

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#2
Idea:
This is to take in consideration after a certain height has been reached
  • Hovers & Turbines become less powerful the higher they go
    • No air, nothing to repel against. Think hover steering
  • Wings & other air-affected blocks need to go faster in order to "catch the wind"
  • Like a curve, the sky becomes less blue and more S p a c e
Should be relatively-simple to accomplish...
 

ZeroGravitas

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#5
I think this is a very powerful idea for its minimal complexity (definitely worth looking at).:)

Have some blocks "upwards push" increase or decrease depending on the height
What not generalise that to all force produced (by all fans, propellers, rotors)?

Splitting the components of the force to reduce the upwards component only would make for weird behaviour with planes as well as making no physical sense.

helis would be easier to tune
I feel like the rate of drop-off of atmospheric density would have to be pretty rapid for this to have a palpable effect at the low level altitudes you'd normally want to hover at, for combat (50-100m off the ground). Have you got an idea for the fall-off rate? e.g. at what altitude it should drop to a half? Like 500m? So most helicopters would be capped out a way below this. (I don't think this would negate the need/value of an altitude hold block/control scheme feature.)

If realistic at all, it would be an asymptotic curve, like this:

f-d c50e02938e0884cfa8b93aab65d16efaac1f11330287d1bbf7edd31b+IMAGE_THUMB_POSTCARD_TINY+IMAGE_T...jpg

It could be approximated to linear fall-off at low altitudes, but it wouldn't be any more work to be more realistic.


This also means the higher airships go the more screwed up Hoverbugs get from weakened hover power
I don't see any (pseudo)physical reason that hovers in hover-bug should be affected by air pressure fall-off. I think that would feel like a very arbitrary impediment being applied to stop them being even more overpowered at altitude... (I think hover bug should continue to work as-is, or be removed, and I don't want that.)


Ion drives - I think should also fall-off in power. The real world ion drives created fairly recently operate by inducing a airflow via rapid movement of charged particles (with very high voltages). So this makes sense, and also keeps ultra-high altitudes the preserve of rocket boosters, anti-grav and adjustment thrusters (unless they are going to be decided to work like ion drives or something). But maybe the ion drives still have *some* residual thrust without atmosphere, like ~10% is purely due to the (blue glowing) ions themselves.

I see this blimp blocks thread from a quick search, you got a different specific one to link?


There's also this thread on atmospheric thinning from early 2017. In which Kris says:
Nice idea, this may be something to consider closer to a time when AI can fly and we make an effort to integrate more flying in the main game. for now, there is no limit.
There's something in the ether at the moment. People keep asking if GC will fly and I'm not sure why they all separately keep asking. They did have some zeppelin blocks planned at one stage, but they were canceled as it was deemed a bit weird for GC to fly. Perhaps we should think about doing them again?
Maybe it's time to pull this out of the ether... I think it would pair very well with @Django's (and @Sdarks) work on increasing draw distance (on PC) and making the horizon look better. e.g. if helicopters wouldn't typically go out of sight of ground and even planes were generally always able to see *something* below them.
 
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ZeroGravitas

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#6
In real life, propeller speed increases at higher altitude (as drag on blades decreases), so thrust doesn't necessarily fall off in direct proportion to pressure. This is how the helicopter drone mission to Mars will work, despite the extremely thin atmosphere there:

But then the sound effects and animation would need to ramp up too, which could be a lot of additional work, unknown. So probably best to leave that alone. (Just reduces prop volume a little with decreasing pressure, to give an idea of getting towards a vacuum.)


Drag reduced with altitude - I think this would be as easy to implement as the scaled thrust for propellers. I believe that currently risistance to movement is just a product of (total) mass. (Possibly slightly more complex, but essentially that.) So that can easily be scaled down with altitude, too.

Reduced wing lift - similarly, just scale it down, why not? Together, these would give a niche for planes with a high wing to weight ratio, which could still fly at higher altitudes with lower drag, travelling far faster. Very interesting and fun mechanic, potentially. E.g. for commuting between different locations (e.g. if the new code for set-piece terrain features has in mind somewhat unique locations worth re-visiting).
 

Sdarks

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#7
Coming from a flight sim background this is definitely something I'm interested in. It's one of the first things I noticed was missing when flying planes in TerraTech. I feel there's a balance to be had here, TerraTech is not a flight sim but it is a physics sandbox so I feel there's a nice middle ground to be found where it's fun but not too annoying or tedious. There's a few things that could be affected by altitude, engines, drag, lift from wings etc and I think expanding on some of them would add some interesting gameplay. It would also link in very well with weather/wind and other things that could affect your flying, as well as some other things like more advanced flight dynamics so you can stall etc.

In real life, propeller speed increases at higher altitude (as drag on blades decreases), so thrust doesn't necessarily fall off in direct proportion to pressure.
To be pedantic here most propellers would actually cut out at higher altitudes. Aircraft engines need a specific mixture of fuel to air, which means as you get higher you need to adjust the fuel to air ratio (as the air gets thinner) to keep the engine going (this could be abstracted away in TT as it's not a fun mechanic). This means that there would be a cap where certain propellers wouldn't work anymore (the ones that seem more like traditional fuel engines) as there's just no air to feed the engines. You'd then get jet engines cutting out at a much much higher altitude. It would make better future and other high tech propulsion sources a lot more useful and unique as well as they wouldn't be affected by the altitude.

I can't say if this will or will not get done at all or any time in the near future, but it's certainly something we've talked about and something I personally want to see in the game.
 

ZeroGravitas

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#8
It would also link in very well with weather/wind
Maybe crossing a complexity threshold there...? (Keep it simple guys.;))

I'm sure these things would add a lot of immersion to the world, but I'm sceptical of how fun they would be; usually when it rains in Terraria, or whatever, one just wants it to stop. Like night time, currently in TT - it's kinda nice to not have it in at all co-op creative (where you just want to build and see what you're doing, etc). And wind sounds like it might just be irritating for flight (take off, landing, etc), in practice. I don't think even KSP has wind...?

To be pedantic here most propellers would actually cut out at higher altitudes. Aircraft engines need a specific mixture of fuel to air
But TT fans/props run on the same unlimited free hub-motor power as the wheels... :p I think there's only the HE small jet engines that seem like they might require both air and fuel.

But sure, even electric props going to loose all appreciable thrust at some altitude.:)
 

Sdarks

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#9
And wind sounds like it might just be irritating for flight (take off, landing, etc), in practice
Absolutely, as with everything you have to find what's fun. Personally I think enough wind that you actually have to pay attention while flying would be fun. Being unable to take off because it's too windy, not so fun. This is all pie in the sky thinking though, there's a reason programmers aren't designers :D
 

Sea_Kerman

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#11
The taking-off-problem would be made less of a problem by making ground level wind only a thing in deserts and salt flats, where you can take off into the wind with no regard for obstacles.
 
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Zonko

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#12
To be pedantic here most propellers would actually cut out at higher altitudes. Aircraft engines need a specific mixture of fuel to air, which means as you get higher you need to adjust the fuel to air ratio (as the air gets thinner) to keep the engine going (this could be abstracted away in TT as it's not a fun mechanic). This means that there would be a cap where certain propellers wouldn't work anymore (the ones that seem more like traditional fuel engines) as there's just no air to feed the engines. You'd then get jet engines cutting out at a much much higher altitude. It would make better future and other high tech propulsion sources a lot more useful and unique as well as they wouldn't be affected by the altitude.
But... there are no engines.
This game uses magic or something.
There are no engines in the game, and they don't run on batteries.
Because the props keep working, even when the actual batteries run out.
 
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