LOS Question

Perhaps if we can get them to fix air combat, we can get them to fix air units LOS. That is really bad. In some ways, air combat in Civ2/SMAC worked the best, despite being micromanagement-y. Although Civ4 system was probably better, I just can't remember it very well.

 

Civ 2 was probably the best designed air visibility system, but Civ 5's worked fine. In Civ 5 you got enhanced visibility from any city with an aircraft stationed there. Simple, but worked well enough. I don't remember how aircraft visibility worked in Civ 4.

Civ 6 the development team created the core for a more complicated system, including visibility from the spot the aircraft is patrolling, but then never followed through on the finishing touches to pull it all together. I'm still not sure how they thought aircraft carriers were going to work in Civ 6.

To me, it has the feel like the designer who was working on air units left the project a few months before the vanilla release, and no one else on the team had the interest to pick it up. So air power has the core of a complicated system, partially implemented, and it's been left in that state for a while now as the designers work on other things they have greater interest in.

 

It is also the feeling that stuck since I started playing with aircraft in Civ6

 

Alright. I had some free time today and took a crack at establishing the basic rules of visibility. So far, this is just explaining the simpler examples where the hexes are in a straight line. I thought it would be good to get a consensus on this framework, before proceeding ahead into the murkier waters of the more complex patterns. Please try to find any holes in my rules! I think it could be a good starting point.

I'll be using the values from the table @Victoria added in the first page of the thread. Honestly most of them are superfluous to understanding the system. Here are the key values:

Sight = 0 for all flat tiles
Sight = 1 for all hills (including forest/jungle)
Sight = 2 for mountains

Sight Through = 0 for all flat tiles
Sight Through = 1 for bare hills, and flat jungle/forest
Sight Through = 2 for mountains, and forest/jungle hills

"Sight Through" is a pretty terrible name, TBH. "Sight Block" would be more appropriate. But anyways I will be abbreviating these to S and ST values respectively. Also, there are three hexes involved with each calculation:

Hex 0 = Tile with the unit in it
Hex 1 = Tile adjacent to unit
Hex 2 = Tile two hexes out.

If my framework is correct, then there are only three important values:
S0. This is the "Sight" value for the hex with the unit on it. Ranges from 0-1 because you can't put a unit on a mountain.
ST1. This is the "Sight Through" value for the adjacent hex. Ranges from 0-2.
S2. This is the "Sight" value for the tile two hexes out from the unit. Ranges from 0-2.

Now let's move on to the rules I found:


Rule #1: If S0 ≥ ST1, "Hex 2" will always be visible regardless of its S value.

This explains the visibility bonus to the hex with a unit on it, and demonstrates why hills, with an S value of 1, provide better visibility than flat land. They allow a unit to see past other hills, or flat forest/jungles, since those terrain types have an ST value of 1.

Example #1:


S0 (Hill) = 1
ST1 (Hill) = 1
S2 (Flat Jungle Ivory) = 0
1≥1 so Ivory is visible.

This is also illustrated by the common situation we all intuitively recognize - being surrounded completely by flat land. In that case, all S and ST values equal zero, so you always can see two hexes out.


Rule #2: If S0 < ST1, AND S2 ≤ ST1, then Hex2 will be blocked and not visible.

This rule defines 100% of the instances in which Hex2 will be blocked from sight. In order to be blocked, both S0 and S2 are compared to the ST value of the hex in between, and both checks must pass.

Example #2:


S0 (Flat) = 0
ST1 (Hills) = 1
S2 (Flat Furs) = 0
0<1 AND 0≤1 so Furs are Blocked

Example #3:


S0 (Hill) = 1
ST1 (Jungle Hill) = 2
S2 (Jungle) = 0
1<2 AND 0≤2 so Jungle is Blocked

This rule also explains why you can never see directly over mountains or forest/jungle hills. Those terrains have an ST value of 2, and all hills regardless of forest have an S value of just 1. It's not possible for S0 to overcome the ST value of a mountain or forested hill, and neither is it possible for Hex2 to have a greater value than 2. Therefore, you can never see over these, regardless of what's on the other side.

Example #4:


S0 (Jungle Hill) = 1
ST1 (Forest Hill) = 2
S2 = 2 (mountain)
1<2 AND 2≤2 so Mountain is Blocked


Rule #3: If S0 < ST1, but S2 > ST1, Hex2 will still be visible.

This explains the instances which do not fall into rule #1, but in which Hex2 will still be visible. Basically, this is why mountains sometimes are visible even when they otherwise wouldn't be.

Example #5:


S0 (Forest) = 0
ST1 (Hill) = 1
S2 (Mountain) = 2

The hill is blocking our view, so S0 < ST1, and this doesn't fall into rule #1. However, since Hex2 is a mountain with an S value of two, this fails one of the checks in rule #2 as well. Hence rule #3 comes into play. Basically, the higher S value allows us to see it despite the obstruction of the hill.


Rule #4: A hex in the third ring can also be made visible, if S0 ≥ ST1 AND ST2, and also S3 > 0

Basically, this extends the sight range into the 3rd hex, but only when there are no blockages in either hexes 1 or 2, and also only when Hex3 is a hill or mountain.

Example #6:


S0 (flat) = 0
ST1 (flat) = 0
ST2 (flat) = 0
S3 (hill) = 1
1 > 0 and the other values are also 0, so we can see the hill.



That's basically what I've got so far. Please, try to prove me wrong!

 

Makes perfect sense to me.
I included the entire terrain table because it had other things like antiquity chances I had not come across before. Apologies for any confusion.

 

No problem at all! I wouldn’t even have known where to find those. It was a good starting point.

 

Great job guys! Thanks for the detailed analysis and illustrative examples.

 

@chazzycat : so how do you think the calculations change when dealing with a unit with normal visibility greater than 2?

 

I assume it works in a similar fashion, just with extra range. Hopefully I will have some time soon again to dive into that (along with the non-straight-line situations).

 

I am disappointed that scouts can't climb up on to the trees on those 2-height forest hills.

 

No kidding. "Climb tree" has worked as a computer game command since at last Zork. What's wrong with these Scouts???

 

I noted the Ironclad's extra sight (when I'd lose it!) long ago. I suspect it's a bug? It probably should be that the Destroyer has 3, and the IC 2, as it it surely couldn't see further than the sailing ships it replaced.

Woods & jungle should block line of site, or that scout upgrade is useless.​

See above - you just need to upgrade them once they've had enough experience getting their hands full of sap

 

I didn't realize ironclad's had the extra line of sight. A bit weird when you see how low a profile Monitor and CSS Virginia had. You generally can't see very far at sea due to the curvature of the Earth. The higher up you are, the further you can see.

 

Exactly. Maybe an improvement in technology gave captains better naval telescopes; but that would have only been enough to keep parity with having someone in a crows nest at the top of a mast!

 

But Civ planets are cylinder-shaped, so I'm not really sure how this would alter the view. I suppose you could see North-South basically forever.

 

smart ass

 

As the first ironclads were metal cans maybe they were an early form of echo location?
I agree though, ironclads 2, destroyers 3... I mean they need to be able to see those subs right?

 

I hope Firaxis include more small "puzzles" like this. I want to discover some of the synergies and what look like anomalies as part of the game and not by reading the manual or the pedia.
I loved finding out that scouts got the "Alpine ability" from Kilimanjaro in Civ 5.
I like how (and when) some of the goody huts in Civ6 give (usually) one really good tech even though I can't remember having read its details.

 

From looking at those values and knowing how the game works I come to the conclusion that the values mean the following

Sight - Sight means how much it helps seeing adjacent tiles. So a forest for example shows nothing, meaning that it does not help see farther.
Sight Through - This means if you can see past the object. You would need to be on a tile with a "sight" value at least equal to the one in question to see past it.

So lets look at a quick example

You are standing in forest and trying to look through a hill.

You have a sight value of 0 and the hill tile is 1, so you can not see through it. You would also not be able to see through a mountain, which is a value of 2.

Now lets pretend you are on a forest hill tile. You have a sight value of 1 now. You would see through a hill tile fine, since you are equal to it, but could not see through a forest hill tile, which would have a sight through value of 2 ( 1 for hill and 1 for forest).

I will also say I am a bit confused on the question in this post, but I am a bit tired so may have missed it.

In the first post, the first example asks why you can't see the hill that is in front of the mountain. Well, according to the rules laid out above, and assuming you can see stuff of a certain height ( lets call it 2) this makes sense to me.

You can always see the tile next to you, so that is why you see the hill immediately adjacent. But like you said, you are standing on a non-hill tile, so your sight is blocked to see anything past that ( except the mountains, which are so tall that they override this sight block). This seems consistent with the rules laid out above.

What part seems inconsistent?

 

And I will explain further.

Your settler is on a hill in that first pic. That means it can see over the regular hill below it and thus around the mountain, but it can't see past the forested/jungled hill to the north of it which is why you have limited visibility that way. The settler behaves with the same visibility rules that everything else does. Your pictures don't appear to contradict that in anyway.

Also, cities always have a range of 2. They ignore visibility requirements from city center. You could have mountains all around your city and still shoot over them. The unit inside of the city, like an archer, is still limited to visibility rules though. So in your screenshot case, once again, the city has its range because it always does and your archer can only shoot what it can see per the establish visibility rules.

Nothing I have seen contradicts any of this.

Edit: I realize this was all explained already and probably better than I did, but I just read the first few posts. Good explanations above with pictures!