unit knowsAbout target

Operand types

unit: Object or Group
target: Object

Type of returned value

Number

Description

Check if (and by how much) unit knows about target.
If unit is vehicle, vehicle commander is considered.

Used In

OFP/ArmA

Example

_kv = soldierOne knowsAbout jeepOne

Comments

#1
toadlife - 19 October 2007
Some background info on this command for all you AI scripting nuts out there:

With Resistance (1.91):
No matter what class of unit the target is and no matter what the skill/class of the enemy AI, the magic 'knowsAbout' number is 0.105.

With CWC (1.46):
No matter what class of unit the target is and no matter what the skill/class of the enemy AI, the magic 'knowsAbout' number is 0.7.

What this means is, the AI will not fire on an enemy soldier until his 'knowsAbout' level of that enemy has reached the 'magic number' or higher.

This suggests that the knowsabout level must reach the magic threshold before a unit knows if another unit is an enemy or friendly unit.

Triggers and knowsabout level:
"Detected by xxx" triggers also follow the above rules.
For a detected trigger to be set off, the knowsAbout level must reach the magic number.

Also...
As soon as An AI unit gets hit with a bullet his knowsAbout level for the unit that shot him will instantly jump to 1.5, even if the shooter is 1000m away.
Vice versa is also true.
If An AI soldier's knowsAbout level for an enemy is 0.7 and the soldier fires and hits the enemy, his knowsAbout level about the enemy will instantly jump to 1.5.
This seems like some sort of AI tweak BIS implemented.
#2
General Barron - 19 October 2007
I have experimented with this command a little, and the truth is I'm fairly disapointed in it.
Basically, this is what I've found:

* A target must be in front of the unit for him to be noticed.
So if you sprint right behind an enemy, this value doesn't increase.

* It takes a couple of seconds for a unit to notice a target, even if he is in plain sight and right in front of him.
So if you run right past a unit, this value might not increase.

* Bushes between the unit and the target seem to have little effect on this value, and trees definately have no affect.
You may be in a forest, and can't see the unit, but he can see you.

* Once the target goes out of sight of the unit, his knowsAbout value doesn't instantly go back down.
Rather, it slowly decreases, taking maybe a couple minutes to go from 4 to 0.
So if a unit spots you, and you then teleport yourself to the other side of the island, his knowsAbout value on you could still be 3 or higher.

I don't have all the answers on this, and I haven't really done extensive research on this command.
But to me, this command seems to fall short of what I wish it could be.
Please post comments on your findings with this command, and if anything I said was wrong.
#3
toadlife - 19 October 2007
Quote:
A target must be in front of the unit for him to be noticed.
So if you sprint right behind an enemy, this value doesn't increase.

Yes, AI enemies do have a very limited amount of peripheral vision, that's not nearly as good as a human player's is.
I've always compensated for this by using a sentry script that makes the unit look from side to side.
This greatly increases their chance of spotting enemies.
I've used the sentry script for guards that stand watch.

Quote:
It takes a couple seconds for a unit to notice a target, even if he is in plain sight and right in front of him.
So if you run right past a unit, this value might not increase.

The time it takes for an enemy to notice you will depend on the units skill level, but I've never been able to run right past an enemy and not have him notice me.

Quote:
Bushes between the unit and the target seem to have little affect on this value, and trees definitely have no affect.
You may be in a forest, and can't see the unit, but he can see you.

Very true and very annoying.

Quote:
Once the target goes out of sight of the unit, his knowsabout value doesn't instantly go back down. Rather, it slowly decreases, taking maybe a couple minutes to go from 4 to 0.
So if a unit spots you, and you then teleport yourself to the other side of the island, his knowsabout value on you could still be 3 or higher.

This is a good thing, and in my opinion it's realistic.
Teleporting with setpos is not something that could happen in real life, so the knowsAbout command shouldn't take this scenario into account.
The reason it slowly decreases is because it makes the soldiers act more human like.
If you see a soldier run over a hill, your are going to still have an idea where he is after he disappears, but your knowledge of where that soldier is will become less reliable, the more time he is out of your sight.
It's not a perfect system, but it's not too bad either.
#4
Unnamed - 19 October 2007
When it comes to what the player knows about the enemy AI, individual trees and bushes do affect line of sight.
An AI that moves behind an individual tree or bush, does eventually return a knowsAbout value of 0.

The generic forest object does not affect the knowsAbout value in the same way as individual trees and bushes.
An AI that moves from the open into a forest will return a knowsAbout value less than if it remains in the open.
Although it will never return a value of 0, even if you can't directly see the AI.
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