I could use GetUnitDefHeight() & unit position. But i do not know where is the center of unit. Engine somehow can detect a unit can't shoot when being under water.

as much as i know, the shooting ability depends on some position of the weapon being underwater or not (don't know the name if the point).

yep, hoijui is right (it was actually possible to shoot from the water with units underwater that couldn't be seen)

you can get a unit's full 3d position in lua

There is no place for lua in C++ AI API.

I don't get one thing. Why BA's sonar station (armsonar) is floating & underwater metal maker (armuwmmm) is placed at the bottom without typical differences in their .fbi files? They both do not have waterline tag set (waterline = 0) and thus for both "floater"= false? Is it hardcoded in engine for building when its "sonarDistance" <> 0? I suspect this because for floating metal maker (armfmkr) there is "waterline" tag set which is logical and provoke no questions.

It's safe to consider pos.y the lowest point on a unit's model.



You would still not be able to detect submarines (I assume that was the point of this question) reliably. Eg. for BA's armsubk, pos.y + height > 0 because its waterline is too small. Even the engine does not know if a unit is intended to be a submarine or a regular ship (game devs can only give it a hint in that regard, see MoveData::subMarine).



They are both placed at the bottom, armsonar can just be built in shallower water (minWaterDepth=10) than armuwmmm (minWaterDepth=15) so it will stick out above the surface more often.

I thought it is the center of the model usually.


Yeah, i already decided to use different algorithms for units with movedef & without. Results are fine at least for BA. The only faulty detected units are Seaplane Platforms because they are both floating and underwater.

I discovered one more reliable way. Any unit has a hit sphere. For now i don't know if GetUnitDefRadius() gives me hit sphere or smth another (can you clear up it?). So, gamedev designs a unit according to its gameplay purposes. If unit is intended to be submarine its hit sphere should not be visible outside the water. So, checking hit sphere it a sensible way to go.


Just checked this. You're right! I was under deep influence by OTA!

That won't always work either. GetUnitDefRadius returns the radius of the model, which is auto-calculated by Spring for some model types and set manually by the modeller for others (units that do not have a defined custom collision primitive use this radius to scale their hitspheres). As an example of what to expect, see:

maybe GetUnitDefHeight() ?

Re-read the first post.