[REL] Realistic Sinking Physics

[sneekyzeke]

Thanx, Leo!

[billko]

Awesome stuff, leovampire!

Bill

[WernerSobe]

Progress Update: I have less time to spend on the project so its going slow. At the moment still reworking the compartment layouts. Here are some pictures of how they will look like. This is an example on Kinposan Maru (medium modern split)


1. Compartment Layout. ALL




2. Only Main Cargo Compartments and Keel

Notice the mid-aft cargo compartments higher then others for destabilisation in roll momentum. This wakes the vessel weak agains capsizing.



3. No Cargo Compartments

[chopped50ford]

thanks for the update. I make out roughly what your doing and all I can say is WOW!, cant wait to see the finished product.

What program are you using to see these compartments?

[Frederf]

I was going to mention the slightly goofy sinkings with the existing RSP mod, small merchants taking water well over the decks for days, DDs surviving insane damage, BBs going down due to minimal damage, etc but I can see that the existing version of the mod is the end of "teaking numbers around" and the next is going to be an overhaul.

By the way that visual compartment model is beautiful. Something I have been wondering though, do warships have an armor belt or blisters modeled? If not and it's not a tremendous amount of trouble (which is most likely would be) could you add 'em?

[tater]

Interesting point. The whole idea of the magnetic pistol was to defeat belt armor. The fact that all you do is set shallow and sink everything is a big part of the problem in terms of tonnage excess. If you have a range of deep running, but you know ou need to actually aim low (even contact) to really hurt them, it changes attacks greatly.

tater

[WernerSobe]

adding a belt is not possible. The way the damage system is designed is a little bit confusing it took me a while to understand how it works. One can remove all compartments from the layout and it will become unsinkable. Compartments are designed as "weakness spots" not as "armored bags".

ill try to explain.

The most important is to understand that dimensions of compartments and their bouyancy are not necessery connected. Meaning that the bouyancy is defined for each compartment type in zones.cfg, while their dimension and location is defined in vessel.zon.

When a torpedo strikes a ship it generates a min dmg and a max dmg bubble. The damage gradualy increases from the smaller max dmg bubble to the bigger min dmg bubble. Every compartment that is inside that bubbles get more or less damaged and starts flooding. The flooding parameters are defined not by the size of compartment but by its type. So if there are two compartments of type NFlotMain flooding they will flood up at same time (assumed they are equaly damaged) even if their size is different. The flooding parameters for each compartment type are defined in zones.cfg. The most important parameter is the floatability or if you want call it buoyancy. So if the "floatability" of that damaged compartments is set to 20. It will slowly reduce the total buoyancy of the vessel by 2x20 during a time period which is defined as the "flooding time". Simultaneously the physics engine will gradualy change the center of mass from the balanced center towards the center of mass of the damaged compartments, again during the flooding time period. This is the point where the size and location of compartments matters. Bigger compartments and those that are farther away from balance point will cause a greater change to center of mass. The vessel will start showing list towards damaged compartments. And finely the third important parameter comes into play "crush depth". This is the depth where undamaged compartments get damaged from water pressure and start flooding. The crush depth for both stock and NSM 2.6 was set way to high. That explains why the ships keep going with decks awash.

Now the hard thing about it is to balance all parameters and compartment dimensions together to realise most realistic sinking.

However a solution can be worked out. Making the lower compartments weaker then the upper ones. So basicly making the main compartment strong with low floatability and the keel weak with high floatability would have the same effect. I will try to realise it for capital warships.

[tater]

That explains a lot. Warships of course have damage control crew (in Real life) so they can be made harder to sink artificially to get a realistic result.

I posted this in my making AAA dangerous to subs thread, and now it makes more sense to me, perhaps it might help in your studies of this:

Hmm. This is very very interesting.

So I dialed the damage down (for 20mm damage mod---made min ~5 to 8 and max ~10). The radius, too. 20mm AP I gave a radius of... 20mm, for example. Others have damage radius 0.02 to 0.4 or so.

Sub is getting hammered for a while. So far so good. I put the skipper below near the chart thinking my spinning death cam might have been "me" on deck getting killed. Below, there are leaks everywhere. Check damage. NOTHING on DC screen. Go back below. More leaks. Lights start blinking. Lights go out. We start taking flooding.
I look at the DC screen. compartments start to flood, stern to bow. flood, systems all go red (water part way up, not total flooding) in that compartment. Next floods, same, then next, then next, all the way to bow, spinnign death cam follows.

I assume what's going on is that the 20mm I made is not actually doing internal damage, but IS taking away hitpoints. At some point, the hitpoints get used up, and the compartment fails totally.

This would actually explain a lot of myster deaths people get. You duke it out with planes, or whatever, and get hit with loads of AAA. No crew are hurt (ever) so there is no reason to avoid autocannon. No damage is ever done---THAT YOU SEE---so you assume all is well. Head towards max depth to avoid ashcans... domino effect.

I'm not sure what yo do. If you make 20mm so it can do any real damage, there is enough of it flying the hitpoints are likely very low. Drop it below the amount that it shows damage to systems without wiping out the whole compartment, and you never know you are damaged until the hull fails catastrophically.

tater

[WernerSobe]

well this is not new to me tater.

There are also compartment parameters for sub compartments.

So when you get nailed by a 20mm gun some hitpoints from a certain compartment are consumed. It is damaged. Not enough to start flooding but when you get below crush depth it will get more damage until all hitpoints are lost then you will have flooding.

[tater]

Yeah, your previous post, and other stuff I had read before, but not really understood became clear to me once I started testing this.

The hitpoints seem like a problem in general, don't they?

[tater]

I think it became clear because unlike a torpedo, which I expect to possibly do very catostrophic damage, the 20mm is tiny pin-*****s. Setting up a situation to be SUNK by 20mm really puts the issue in relief.

[WernerSobe]

maybe i have a solution for you.

If you make the AA guns do as low dmg as possible. Something that is so low that it wont hurt ships much. Then set the hitpoints for plane compartments (yes they have compartments too) to something like 0.00000015. That should make the flaks being only usefull agains planes. I warn you thats a lot of tweaking, restarting the game over and over :-)

[tater]

Yeah, I know the restarting, lol.

(as an aside, I notice that after a CTD, the game reloads in a fraction of the time...)

As for the AAA, I'm not working on the AA vs planes, I'm working on the AA vs our SUBS.

If you surface your sub next to a small combatant with AAA guns, or even a CV, loaded with AAA, they will shoot and shoot and shoot at the sub---and do no damage* to the sub, and more importantly zero damage to the deck crew.

This makes surface actions very unrealistic. If a sampan or trawler fought back with machine guns or 25mm in RL, the sub would back off out of range. In game, you can safely ignore AAA.

*caveat, now I understand that each one of those hits removes hitpoints, weakening the hull.

tater

[WernerSobe]

bad news: im stuck for two days already with the fuel bunker explosion under water. When the ship is sinking by flooding and the fuel bunker gets under water it explodes always. Then you have that stupid looking explosion sticking out of the water.
The problem is old you can see what i mean on page 4. There is a screenshot.

I dont know what triggers it. The game seems to ignore compartment parameters for fuel bunkers completely. It doesnt make sence but it ignores crush depth, hitpoints or any other parameter. When the game sees its a fuel bunker it ignores the other settings and just make it explode as soon its under water.

The only way out is to remove the fuel. Then they act like normal compartments. So there is also no explosion by a direct hit. Seems there is no other way to fix it.

So my question is: Whats better? No fuel explosions at all, or stupid looking fuel explosions every time the ship is half under water? I could also try to replace the fuel explosion by big fire. big fires do not trigger under water.

[Fearless]

Originally Posted by WernerSobe

bad news: im stuck for two days already with the fuel bunker explosion under water. When the ship is sinking by flooding and the fuel bunker gets under water it explodes always. Then you have that stupid looking explosion sticking out of the water.
The problem is old you can see what i mean on page 4. There is a screenshot.

I dont know what triggers it. The game seems to ignore compartment parameters for fuel bunkers completely. It doesnt make sence but it ignores crush depth, hitpoints or any other parameter. When the game sees its a fuel bunker it ignores the other settings and just make it explode as soon its under water.

The only way out is to remove the fuel. Then they act like normal compartments. So there is also no explosion by a direct hit. Seems there is no other way to fix it.

So my question is: Whats better? No fuel explosions at all, or stupid looking fuel explosions every time the ship is half under water? I could also try to replace the fuel explosion by big fire. big fires do not trigger under water.

Treat it as if there were still air pockets in some compartments filled with fumes. There still could possibly be sparks going around even when the ship went down.