Sensors and AI Perception in SH3 and GWX

[Kpt. Lehmann]

Please bear with me a bit here. Though we can understand,
observe, and mod the sensors in an effective way... I am not
a very good instructor.

In SH3 there are several files which control sensors. I'm not
going to discuss how to mod the sensors and ASW package
here... as it could lead to pages and pages of intensive
discussion that I really don't have the time or energy for.
(No offense... after months of working and modding them...
Hair loss and blindness are a seriously concern me.)
Generally speaking though...

Just a quick recap for those who don't spend much time (or too much time lol)
considering sensors in SH3. In SH3 you have several types of Sensors and detection methods.

Definitions of sensor action:

A) Passive Sensors - Detection is acheived by simply
listening to or observing the environment. Hydrophones fall
into this category

B) Active Sensors - Employ an artificially generated signal
that must return to the observer by striking an object and
being returned to the sender.

Sensor Types:

1) The Visual sensor: (passive detection) Think of this as
the element comprised of the Mark One Eyeball. At sea, this
element is nearly ALWAYS augmented by powerful optic devices
like binoculars, both hand-held or ship mounted. NOTE:
Shipboard optics were nearly always more powerful than U-boat
mounted optics. U-boats generally relied on watch-crews
employing hand-held binoculars. On a clear, calm day with
good light in real life, you can see in excess of 32km. Representing
these ranges properly in SH3 would create a situation where
the demands on the user's PC would be too great to function
effectively... Therefore this one element causes us to think
in smaller terms than in real life... either in an 8
kilometer or 16 kilometer three dimensionally rendered
sphere.

2) Radar: (Active detection) used by surfaced submarines,
vessels, and aircraft. This method generally uses a radio
signal transmitted by a sending device that records data
reflections from a successful return upon successful contact
with an object.

3) Hydrophone (passive detection) You can think of this as
putting your ear to a railroad track... or connecting the
listener directly to the water. Water conducts sound more
effectively than air by MANY times over... allowing you to
hear much farther than you can see even on a clear day.
Hydrophones allow you to see beyond the horizon.

4) Sonar/ASDIC: (active detection) Simply consider this a
submerged version of radar and you are golden. However,
ranges are generally REDUCED as radio signals are impeded
rather than magnified by water.

5) Radar warning: Detects the signal of a radar and alerts
the user. (Sometimes used by the enemy to home in on the U-boat LOL)

6) Radio Direction Finding: Though there are more than a few
who feel that this is a broken function in SH3... I believe a
representation of it exists to some degree in-game. I can
only offer my own experiences in reporting this means of
detection by the enemy and by the apparently active values
one can find in the Airstrike Configuration file. (At the
very least, the enemy AI will send some sort of distress
signal... which we can all attest to having attacked single
merchies only to have a DD or enemy aircraft attack soon
after.

From Stock SH3: (an example of implied function of the Radio DF)
"Enemy Air Strike Probability Increase on Radio Messages
Sent=30 ;[>0] Increase over the default probability
on a radio message sent
Friendly Air Strike Probability Increase on Contact Report
Sent=50 ;[>0] Increase over the default probability on a
contact message sent
Enemy Air Strike Probability Increase on Player Detection=50
;[>0] Increase over the default probability on player
detection."

OTHER IMPORTANT SENSOR FACTORS AND NOTES!

The "Command sensor" in SH3:
In SH3 only ONE sensor is actively in use at any given
time... This is true whether it is your own U-boat and
crew... or an enemy vessel or aircraft. The available sensor
with the highest maximum range is typically the "command
sensor" and OVERRIDES other sensors that may be available at
the moment.

The periscope in SH3 created the night vision bug. The
player U-boat crew unreasonably spotted distant objects...
due to the fact that in effect, the periscope could see
through its protective shroud even though it was retracted.
Additionally, to understand this better... you can think of
the periscope as a watch officer AI crewman. The trigger for
this to occur in-game is the moment the red light goes on in
the F5 navmap screen. (The actual moment that "night"
in-game begins to dominate certain behaviors of the AI.)
The enemy also subject to the night vision bug, though not
quite as badly as the player U-boat crew is in stock SH3.
They see too well at night all the time and the only way to
completely correct them at night causes other problems such
as blindness during broad daylight.

(Something else I've noticed regarding players speaking about
the vampire night vision bug... Their radar is "on" and as a
result is the "command sensor" which reaches farther than the
maximum visual range of the player AI watch crew. Players
sometimes mistake this as a visual spotting. The AI watch
crew cannot see beyond 5000 meters at night.)

Light factor: Both your own AI crew and enemy AI crews are
heavily influenced by this value.

Crew efficiency values: Enemy aggression is
HEAVILY influenced by crew effieciency rating. Crew efficiency
values below "veteran" often appear quite useless... and even
large numbers of otherwise effective "elite" crews can be
subject to traffic jams allowing the player to motor away
quite readily if the modder isn't careful.

Progression of technology in the war and AI crew efficiency
values are represented in SH3. This was preserved by the GWX
dev team.

Limitations born of design and necessity in SH3:
The size of the three dimensionally rendered world is an
understandeable limitation... 8km or 16 km is the norm...
However, on a calm clear day with good light as mentioned above...
visibility in the real world can exceed 32 km. Mirroring such things
ACCURATELY in SH3 would keep most of us from playing due to
impact on the system. (Maybe in a few years aye?)

In SH3 there are only two PRIMARY types of player hydrophones
modelled. (GHG and KDB) In SH3 only one range value can be
set for the maximum range of each hydrophone. In real life, single
ships could be heard a little over 20 km and convoys could be
heard at over 200 KM!!!! Again, in SH3 we can only set one
maximum range for each hydrophone... In GWX these values were
set VERY conservatively. (Somewhere between 20-30 km... I
don't want to just come right out and say it here... because
I don't want to ruin things by giving players exact
information on a sensor where real-life variables cannot be
modded in a more interesting way.)

Water temperature, salinity, and many other variables
affecting sensors are not modelled in SH3. There is no real
apparent random factor modelled for that matter. In real
life, maximum performance values are condition dependant,
meaning that even a directly stated value is an averaged or
generalized value.

Many people do not realize that in real life a single depth
charge could ruin local hydrophonic acoustics for as much as
10 minutes... I've heard this described as a "sizzling" sound
by the massive amount of bubbles released. This has been
modelled in part by using one method or another several major
mods... The same is true of GWX.

In SH3 any ship moving faster than 15 kts is not using its
hydrophone.

Acquisition of contact vs maintaining contact: For both
player and enemy AI crewmen in GWX, it is much harder to make
the initial contact... than it is to maintain that contact.
You can practice this in real life. Simply spot an airplane
and watch it until it is almost invisible... then look away
for a moment... It will be harder for you to re-aquire
visual contact. :O) The same can be said of hydrophone,
sonar, and radar contacts. In one way or another all means
of detection are subject to interference or "noise."

Reminder- The AI itself in SH3 cannot be modded... only its
peripheral perceptions of the environment can be altered positively or negatively.

For GWX players. Further modding WILL cause negative
side-effects in-game. Modding the sensors in SH3 really is
like trying to tie your boots without enough string.

For the most part in GWX... all we needed to do to make the
sensors more effective... was to heighten their sensitivity
to the environment... and tolerating what felt like AGES testing the
effectiveness of each class of sensor... with each AI crew
efficiency level... one value at a time... This translated
into months of focused, boring, and tediously repetitive
work.

For me personally, it feels like I spent a lifetime waiting
on the loading bar!

No doubt some will complain... or continue to make their
subtle little digs at what we've done. I've seen the word
"ubered" tossed around quite readily by those that feel we've
made things too tough... and the implication is made that we
made changes to the sensors in an irrational fashion. I view
those as simply opinions born of players that are having to
get out of their comfort zone! Others may even claim that we
don't know what we are doing.

Whatever.

At the end of the day... in all cases regarding the sensors
and ASW package in GWX, arbitrary decisions had to be made
based on in-game performance to offer the player a stiff, but
not un-breakable challenge that increases in difficulty with
the progression of the war.

Every modder who has ever worked on the sensors in SH3 has
had to make similar decisions weighing real-life (often
foggy) currently available research data in comparision to
the means of simulation.

Seriously, all of us have our own ideas of what "realism" is
based on what we see and interpret.

Only the guys who fought the real battles have any true right
to talk about "how things really were."

Now before anyone starts complaining about the SH3 Devs and
the limitations of SH3 itself... I have to say, throughout
the course of developing GW, I've grown to have what I feel
to be a special understanding of the challenges involved in
bringing such a complex piece of work to the table.

To try and describe the process of building GW and GWX, it
felt like walking into a famous cathedral that needed
renovation from the ground up... masonry, painting,
artwork... the entire massive lot. Expectations abounded,
and nay-sayers surrounded. To stand back and look at the
work as a whole prematurely, was imposing and frightening.

You guys are a demanding lot LOL...
but in the end it was the ghosts of the past that drove us
along with unrelenting force. Their story must be
remembered.

We are lucky to have SH3... and luckier still to have SH3
with a dynamic campaign. We all know it has its quirks...
but it does the job better than anything else out there in my
opinion.

The problem with modding and/or being an artist... is the
simple act of choosing a place to stop... and calling a
creation that will never be perfect for everyone on every
occasion... "FINISHED!!!"

Add-in real-life trials and tribulations... and a deadline or
two... and you can find yourself in a personal hell of your
own making LOL.

Sorry for the ramble and speaking in such general terms. I
just don't have the diesel left in the tanks anymore for a
long winded tech-discussion on such matters. I hope you will
settle for this overview. Except for the stray detail here and there,
it is likely to be a detailed as I ever get in reference to what we've done.

If you find it un-satisfactory, feel free to use other
mod-packages apart from GWX. In the end, it still boils down to
individual taste based on in-game experience... not miles and
miles of text... or publicly and loudly stated opinions.

Sink them all!!!