Sub/ship acceleration too fast??

[Oesten]

Hi All,

After figuring out the number format used in the SHIII files I have tonight spent a couple of hours experimenting with changes to the uboat .sim file.

I could use some help from people who have specs on the boats we have in SHIII, because I can see the values for (I think) disel engine shp and rpm. I am not sure if the values are per engine or both included.

I have started with the VIIb as this is the boat I use the most. The default values are;

SHP 2800
RPM 471

By decreasing the SHP value I can reduce the acceleration of the boat, but this also reduces the top speed.

By increasing the RPM value I can increas top speed without effecting the acceleration (much). So to the limited extent of my testing tonight we may be able to (at worst) reduce the acceleration problem and (at best) fix it. This of course assumes I can get some real acceleration figures for these boats.

I don't think it will be possible to alter the acceleration profile, just the time to a specific speed.

Anyway, here are the tests I got tonight.

Std VIIB
SHP 2800
RPM 471
0-10 6 secs
10-17 45 secs

Modded VIIb
SHP 1800
0-10 8 Secs
11-15 50 Secs

SHP 1000
0-10 16 Secs
11-15 50+

SHP 500
0-10 33 Secs
11-13/14 2-3 Mins (only 14 infrequently)

SHP 500
RPM 600
0-10 30 Secs
11-15 2+ Mins (got back the 2 knots)

Later,

Grayarea.


Grayarea:

Just found this post, sounds very promising! Made any progress?

Oesten.

[timetraveller]

Nice find, Grayarea. I never thought that RPM was any more than visual eye candy.

Someone else on the forum some time ago said they were able to change the sub's drag factor to effect acceleration. They even gave an example, but I was never able to make it work.

Good luck on your changes.

TT

[Beery]

As one who was frustrated by the constant collisions in SH2, it may be that the devs used these unrealistic accell speeds to help out their AI avoid collisions in convoy situations, or wherever several escorts are hunting together. It may be that realistic accell rates will greatly increase the amount of collisions. Pure supposition on my part, but just may be a reason things are the way they are at the moment.

Regards

I'm almost certain that this is the reason for the high accelerations. Without them, we'll have lots of ship collisions. Having seen the effect of that sort of situation in other games (B-17 II) I have to say that the current situation, while not perfect by any standards, is much better than the alternative.

[Beery]

Unlikely. Higher acceleration would lead to more collisions, if anything. Slower vessel speed means more time to correct heading to avoid a collision.

It's not the acceleration or high speeds that cause the problem - it's caused by a lack of situational awareness on the part of the AI. The ability of ships to transition quickly to reverse prevents collisions, and if you slow that transition time, you make collisions almost inevitable. The AI is much more likely to collide with things even at slow speeds because it is incapable of projecting courses, so if you take away the AI's ability to manoeuvre when it finally does see a definite obstacle, you compound the problem.

I have no doubt that correcting the acceleration times will cause a whole lot of problems. What will happen is that convoys will be unescorted, because the escorts will have collided and sunk by the time you reach them. Then you'll find convoys smaller than expected for the same reason. Most annoying will be the actions of escorts when their hunting program gets triggered - even if they manage to avoid ships between them and you, they will almost certainly run into each other when they're trying to sink you. Trust me, no one will like realistic acceleration times unless we can also somehow improve the AI's situational awareness. We'll have a situation where ships behave stupidly and chaos will ensue (in a very visible way - think explosions and convoys full of ships on fire - and none of it caused by torpedoes). It will look silly because players will see constant collisions whenever two or more ships are in close proximity to each other.

[Oesten]

Beery:

Good point. However, it's ACCELERATION that we want to slow down to realistic levels, not DECELERATION.

Maybe modding acceleration will not affect deceleration rates. That needs to be tested.

Now, assuming that slowing acceleration DOES NOT slow deceleration,

The question is, how does the AI work? When two AI ships are about to collide, we have two ships.

Ship 'A' is the ship that wants to move into a space that another ship is occupying.

Ship 'B' is the ship 'in the way' - the ship occupying the space that Ship 'A' wants to move into.

Now, when a collission is imminent, is it the responsibility of Ship 'A' to stop and wait until Ship 'B' is out of the way,

or,

is it the responsibility of Ship 'B' to accellerate rapidly and move out of the path of the oncoming Ship 'A'?

The answer to this question provides us with the answer as to whether nerfing accelleration will result in more collisions.

If the AI avoids collisions by making Ship 'A' stop and wait, then nerfing acceleration is OK, because Ship 'A' will slam on the brakes and wait however long it takes for Ship 'B' to get out of the way.

If the AI avoids collisions by making Ship 'B' speed up to get out of the way before Ship 'A' reaches it, then nerfing acceleration will cause collisions.

So, a test needs to be made. We need to set up a custom mission with two AI ships, with Ship 'A' waypoints leading it to ram into the side of Ship 'B'. Then both ships need to be monitored to observe their behavior when collision is imminent. Is it Ship 'A' that takes evasive action, or Ship 'B'?

[Beery]

Beery:

Good point. However, it's ACCELERATION that we want to slow down to realistic levels, not DECELERATION.

Maybe modding acceleration will not affect deceleration rates. That needs to be tested.

By all means test it, but I very much doubt that it would use a different routine. From the programmer's standpoint, what would be the point of making two different routines for what is essentially the same procedure? It's ALL acceleration. Deceleration only occurs when acceleration is complicated by travel in a contrary direction to the current acceleration.

As for collision avoidance, what happens depends on the situation, but the faster ship usually does the manoeuvring.