Water-less Caves

P4R4D0X1C4L · October 2016

Now I understand that we have no clue as to how the planet formed currently; the most we know is what we have learned from PDA's. One immersive issue I have however, is the lack of underwater air-pocket cave systems. Have you ever done the trick with a cup where you stick a tissue inside a plastic cup, turn it upside-down, and force it under water? The same principle applies, but minus the force and just add the cave system. Now, I understand that some caves form as a result of erosion, but even then, depending on the currents and sea level, these air-pockets can very easily form at nearly any depth assuming the water pressure on the ceiling does not cause a cave in. I'm curious on other's opinions of this, and if you think it would be a nice/fun/interesting factor in the game.

morryatay · October 2016

this sound cool, but currently the only terrestrial mobs we have are the cave crawlers... and there are to many of those nasty buggers already...

if there was something truly horrifying like a giant water spider/scorpion living in these caves then i could really dig it, cause as we all know subnautica is a horror game in disguise...

P4R4D0X1C4L · October 2016

Actually, they really got rid of a lot of the cave crawlers. They used to be all over the Floating Island, and now there was only one I found inside the actual base. Same to the Mountain - I think I only found 1

EvilSmoo · October 2016

Not unreasonable, if Handwavium can be used to construct some plausible explanation for a cave to have an air supply.

The trick is, everything at that depth is the same pressure, or inside a reinforced titanium hull. Rock would probably crack pretty quickly, and I'm not sure how air would work with water at 1.5km deep. Anyone got the maths on them? Would super-high-pressure water crush air in an enclosed pocket? Or could air at high enough pressure push down water enough to work?

That, and the biggest consideration: can the engine do it? If it's just a matter of placing another air/water barrier of limited size, then it could really be cool enough to do regardless of whether or not it should actually work. Call it a hi-tech force field and make the cool cave, perhaps an old "nature sanctuary" of surface plants? With a working or broken artificial sun in the ceiling?

P4R4D0X1C4L · October 2016

You make a valid point. I forget that a lot of these game engines rely on there only being one source of water and every source is the same level. You propose and excellent counter-point, good sir. Points to you. I did account for the math though, and I just am under the assumption that air pockets wouldn't exist in super deep areas.

EvilSmoo · October 2016

I dunno. In some movies, they used high-pressure air mixes to ease the hull strain. And in Abyss, they used that liquid-breathing helmet that drowns the user in oxygen-carrying fluid that cannot crush at ultra high pressure.

But watch this regardless:

Fathom · October 2016

Have a Purple Brain Coral grow in a cave and the bubbles should fill it in eventually as long as the air does not dissipate through the rock faster than it can be produced. You'd just end up with a high pressure air environment instead of a high pressure water environment. They could make the transition work similar to the Moonpool engine wise.

EvilSmoo · October 2016

http://www.calctool.org/CALC/other/games/depth_press

Pressure at 1.5km is almost 150 atmospheres (149.806).

http://www.scubadiverinfo.com/2_physics.html

So... I have no idea how air would behave in really deep places, and am not willing to try to do the math. A little below the surface, sure, a sealed cave would be fine. If a coral is emitting bubbles, those bubbles should actually be growing significantly on the way to the surface.

But again, if it looks cool enough, screw it, stick in underwater air cave somewhere with alien glowy thing on the entrance and if anyone asks, wave your hands and say "alien technology, wooooo."

P4R4D0X1C4L · October 2016

I like that logic @EvilSmoo xD

Nautical_Nick · October 2016

I would LOVE to see this in-game!!

CAPSHAW · October 2016

EvilSmoo wrote: »

I dunno. In some movies, they used high-pressure air mixes to ease the hull strain. And in Abyss, they used that liquid-breathing helmet that drowns the user in oxygen-carrying fluid that cannot crush at ultra high pressure.

But watch this regardless:

God help us if we find a gigantic sphere

CAPSHAW · October 2016

EvilSmoo wrote: »

http://www.calctool.org/CALC/other/games/depth_press

Pressure at 1.5km is almost 150 atmospheres (149.806).

http://www.scubadiverinfo.com/2_physics.html

So... I have no idea how air would behave in really deep places, and am not willing to try to do the math. A little below the surface, sure, a sealed cave would be fine. If a coral is emitting bubbles, those bubbles should actually be growing significantly on the way to the surface.

But again, if it looks cool enough, screw it, stick in underwater air cave somewhere with alien glowy thing on the entrance and if anyone asks, wave your hands and say "alien technology, wooooo."

So that is a valid point on the caves. They would have to be extremely shallow. Fluid pressure acts in every direction, including up. Imagine a tube shaped like a J, or a U but one side is much taller. When you start to fill it up, water will fill on both sides until the surface is above the top of the bend. Now, if you keep poring water in, the level of the water will not very visibly increase on the closed side. Now if you fill the other side up. say to 6 feet tall, you have the weight of 6 feet of water times the cross-section of the tube on the air on the other side. Air can change its volume, and become more dense, which leads to an increase in pressure and temperature, but the water will absorb the extra heat quickly and you will be left with a very high pressure atmosphere. 1.5 kilometers below the ocean, the water pressure is at 150 atmospheres. I don't know how to calculate the air pressure needed to sustain that, but I assume it would feel like you are breathing water, if it didn't crush you (but apparently water cant in this game so what am I even saying). This post has gone too far, so I hope you are beginning to understand/

CAPSHAW · October 2016

It would be 2,190 psi, and would be the same as if you were in the water at that depth.

EvilSmoo · October 2016

In reality, it's not a huge deal, as long as everything is at the same pressure. And does not want to go to a lower pressure area. Air cave could work, just as long as the water pressure doesn't make the gas into a liquid, or something else weird.

That, and the devs are unlikely to actually put in nitrogen narcosis, simply because it would be a fairly obnoxious mechanic. Same as how oxygen tanks last far shorter at greater depths, while ingame X seconds at 10m deep lasts you the same time at 1.5km deep. Reality can be boring and stupid, so having air-filled caves at whatever depth could be worth it, as long as it's cool.

CAPSHAW · October 2016

I guess this only works in a realistic environment. The face that the characters body and oxygen tanks isn't crushed when they get out of the Seamoth in most places is unrealistic. Here is a water phase diagram to show what I was saying. If you look up a phase diagram of air, it is still a gas. I thought this was one of those threads where we decide if it is real or not. If we decided it wasn't, we would have to protest the moonpool and I am not ready for that. I like the unrealistic gameplay. I still play SWBII on my ps2, and wonder why it ever had to change.

CAPSHAW · October 2016

Evilsmoo, after seeing your video I really hope the developers have some homage to Sphere like they did with Holy Diver. It was a shame that hardly anyone understood that message.

P4R4D0X1C4L · October 2016

I'm happy that this idea inspired debate

TotallyLemon · November 2016

morryatay wrote: »

this sound cool, but currently the only terrestrial mobs we have are the cave crawlers... and there are to many of those nasty buggers already...

if there was something truly horrifying like a giant water spider/scorpion living in these caves then i could really dig it, cause as we all know subnautica is a horror game in disguise...

TotallyLemon wrote: »

QuillShot wrote: »

Edit* I know its not exactly a horror game, but I really think it has the potentional for great dynamic horror aspects.

That's exactly it. Subnautica is NOT a horror game. Horror games exaggerate frightening circumstances to create suspense and fear. Subnautica has suspenseful elements, but they are a byproduct of the survival genera, and not a focus. Subnautica has creatures, not monsters and abominations.

04Leonhardt · November 2016

So one of the ideas for the Arctic Biome was to have frozen caves, rather than surface glaciers, because that would be stupid to have it next to a tropical island.

Now imagine the Arctic caves being inside an air pocket and walking around in an underground alien winter wonderland with "christmas lights" in the form of bioluminescent flora and fauna.

It'd be glorious.

04Leonhardt · November 2016

Accidental double post
I need to go to bed

dealwithitdog · November 2016

04Leonhardt wrote: »

Accidental double post
I need to go to bed

Shhh... No more tears... Only dreams now...

Water-less Caves

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