Taking Slamers as basis probably the easier way to reintroduce Subs would be make they hover underwater... but, this would work more like a place holder
From my understanding, the problem with subs isn't making them submersible. We obviously have that. The difficulty is all the conditional stuff with subs. They can only be seen with sonar or underwater vision. Not when planes fly overhead. But then again, we have the orbital layer functioning which is exactly that. So. *shrugs* Maybe Uber just doesn't think they're important enough right now. If that's the case, I disagree with Uber.
I understood it was more to do with creating a new layer, in the sense that it would need to be similar to Water Surface in that it could detect the meeting of water and land, but harder because it's not at height = 0. There would also be aspects of having to move/target between layers, and the ability of weapons to do the same. Not insurmountable of course, but just a lot of dev time to do. Also see: https://forums.uberent.com/threads/uber-i-figured-out-how-to-get-subs-to-work-i-think.62600/
right now they focus on polish and are on a feature freeze ... subs will make a comeback eventualy ... it seems to be rather a question of overcoming technical difficulties and time ... but to me the general issue is that naval just is too limited to be of any major use save for waterheavyplanets and it still needs tweaking ... so to me in order to have naval matter players must generaly start on waterheavy planets that are resourceheavy aswell ...
Except we already have a submersible layer and have had that layer for a while. We also have the orbital layer which has some similar behaviors. And we already have submersible bots, which have similar behaviors. So it would seem that most of the core concepts are in the game.
Submersible layer and walking on the ground underwater are not the same. Subs don't go on the ground, they go in the water, under the surface. The amphibious units go on the ground under the water, and ships go on the surface, subs are a new layer in between the two.
The sub layer existed in name only. When subs were in the game, they were just ships that looked like subs. Orbital has no "terrain", it's just an empty layer that units can go anywhere on. Submersible bots follow the sea floor, so they are just land that ignores the land/water barrier - this is a different layer to what subs need. For subs to work properly, they need to exist between the water surface and the sea floor. Which means working out where that intermediate depth (or depths, if all subs don't share the one) intersect with land. And then forming nav meshes around that, and doing transitions between the surface and sub layers. It's also possible to have situations where subs can't surface. For example, overhangs/tunnels.
Well, it is target able "supposedly" by most kinds of weapons. So it does classify as a different layer.
Consider the difficulties the current naval has with navigating shallow water. Now consider that the submarine layer is basically the same, except that it has twice as much shallow water to deal with, and it shares the water with the naval layer (unlike the other layers, which can usually ignore each other). Another issue might be that submarines shouldn't be able to see the coast, but the fog of war system doesn't support that. But maybe submarines seeing the cost isn't such a bad thing? The rest are not really serious issues, but just cool features that inevitably get added on and consume time: Sonar. Invisibility. Surfacing/Submerging. Weapon-water interaction. Ship/Sub/Seafloor collision. Above/below water targeting. Sub pen factory. Scathis balancing two naval hierarchies.
The problem with them, is a lot of the problem with naval atm. Things with torpedoes can't fire on land, which is fine vice versa but things that have torpedoes or a weapon and fires both is unbalanced. Subs must submerse, visually the water must be deep enough, but it's not WYSIWYG, there is no way to tell deep water is deep, just like there is no way to tell if a land bridge can be crossed through shallow water which it often can. You will build a sub pen for instance, just to realize that it is in a "mini-lake" of deep water surrounded by shallow water and the factory is a wasted budget. Speculation sure, but that is what I think it is, and it would take a massive redesign to make the map recognize water generation and emboss it deeper so subs have less grey area, as well as making it more visible to players what subs can and cant reach. Which is why they are trying a middle ground on current naval generation and how naval can play uniform. Making amphibious act like surface and all naval fire at each other above or below water the same would be an easier fix. The other thing that can be done, is making submarines not submerse, but giving them a new fake layer of invisibility and "sonar". That ways, submarines are invisible even though they appear like regular ships on water, but nothing can see it without revealing on sonar.
