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Line-of-sight issues on hex maps

22 replies [Last post]
Tue, 06/21/2005 - 18:44
OutsideLime
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Joined: 12/31/1969

Hello gang,

Long-time lurker, posted a few recently....

Aaaaanyway

Among the many thousands of games I'm working on, there is one that uses a static hex-map as a battlefield. The game is fairly typical, a configure-and-deathmatch-giant-robot-game (my avatar is an example of one of the robots in the game) with far too many rules. I have been wracking my brains for ages to try and figure out a logical way to work out, and concisely explain, how line-of-sight (LOS) works for directional attacks.

For example.

Say my robot has a laser with unlimited range. It can fire in any of the six linear directions no problem. But what if I'm standing in the middle of an open field, no obstacles, and my target is standing one hex to the left or right of my straight line? Obviously it should be targetable, but how to explain that? "Obvious targets are legally in range."? Nah. Too blurry to be a real rule. What about when obstacles start coming into play, and sort of half-way block the "obviously in range" LOS? one-third block it? fourteen twenty-ninths block it? The rule becomes even blurrier.

So far I'm sticking with "Your robot is programmed to fire directional weapons in the six directions outward from your robot, period. Deal with it." But I'd like to know if anyone's tackled this problem before with any success, or has any ideas on the matter.

Thanks,

Josh

PS - and I've thought of using a string or ruler to see if any obstacles are encountered.... not fond of the idea, but does anyone else use this tactic? Does it work?[/i]

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Tue, 06/21/2005 - 18:54
#1
dete
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Joined: 12/31/1969
Line-of-sight issues on hex maps

did you do that avatar art work yourself? IT IS AWESOME!!!

I'm workin on a giant robot battle board game too.

Mine is not Hex so I don't have these problems.

I don't see why you can't have a card that indicates all
the places you can target (just a map colored showing
where you can hit)
And just imagine that even though it was a hard shot, your
robot/pilot pulled it off.

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Tue, 06/21/2005 - 19:11
#2
OutsideLime
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Joined: 12/31/1969
Line-of-sight issues on hex maps

dete wrote:
did you do that avatar art work yourself? IT IS AWESOME!!!

I'm workin on a giant robot battle board game too.

Mine is not Hex so I don't have these problems.

I don't see why you can't have a card that indicates all
the places you can target (just a map colored showing
where you can hit)
And just imagine that even though it was a hard shot, your
robot/pilot pulled it off.

Thanks, I did do the artwork myself; I'm an illustrator by trade, game designer by obsession.

The targeting map doesn't work because you can't account for the endless variations on obstacles, and using obstacles for cover is a critical defensive tactic in the game.

My game started on a square map too, but I converted to hex in an effort to make movement more natural and to do away with diagonals.... now I've got this problem...... thanks for the try though!

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Tue, 06/21/2005 - 19:13
#3
Nando
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Joined: 07/22/2008
Re: line-of-sight issues on hex maps

OutsideLime wrote:
But I'd like to know if anyone's tackled this problem before with any success, or has any ideas on the matter.

Forum Search is your friend.

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Tue, 06/21/2005 - 19:25
#4
Anonymous
Line-of-sight issues on hex maps

Does anyone use "rubber bands" for line of sight anymore?

When I was into the FASA Star Trek Tactial Starship Combat game, we used a rubber band (cut so its a rubber string) stretched from the center of the target to the center of the firing hex. Makes it pretty clear what obstacles are in the way and shows the direct path, just like drawing a line would, except you dont wind up with a messy board ;)

C.

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Tue, 06/21/2005 - 21:07
#5
OutsideLime
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Joined: 12/31/1969
Line-of-sight issues on hex maps

Forum search did turn up some good conversations on the matter, but nothing that I'd consider to be a solution. Thanks for the tip though, I've been hitting the wrong "search" button till now (the field at the top of the page) and always getting zero hits.. that slapping sound you hear is me smacking my forehead...

Well, maybe I'll try the mechanical solution... A string or ruler with range increments marked on it... it wouldn't need to be used on every shot, only contentious ones....

Back to the testing table I guess....

Don't give up on me though! Still wanting to hear other ideas!

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Tue, 06/21/2005 - 21:33
#6
dete
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Joined: 12/31/1969
Line-of-sight issues on hex maps

Eureka!

From the string/ruler idea!

different guns have different gun trajectories.
These trajectories are made by a cut out target map
that you use like the ruler and can place on the
battlefield to see if you can hit the enemy.

This will even work for flame throwers that can go
around objects.

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Wed, 06/22/2005 - 10:30
#7
Shrike
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Joined: 08/26/2010
Line-of-sight issues on hex maps

Hey there, if you're doing hexes why not go the simple route have a firing arc instead of LOS? In the rules show where each arc is and then just give modifiers for the to hit roll for obstacles. A small woods adds +1, heavy +2.... put a limit on how many mods can be added until you lose the ability to fire. This is basically what was done for the Battletech hex map game and I never saw any problems with it... I've seen other hex games that have used it too...

Shrike

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Wed, 06/22/2005 - 11:35
#8
phpbbadmin
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Joined: 04/23/2013
Line-of-sight issues on hex maps

Shrike wrote:
Hey there, if you're doing hexes why not go the simple route have a firing arc instead of LOS? In the rules show where each arc is and then just give modifiers for the to hit roll for obstacles. A small woods adds +1, heavy +2.... put a limit on how many mods can be added until you lose the ability to fire. This is basically what was done for the Battletech hex map game and I never saw any problems with it... I've seen other hex games that have used it too...

Shrike

What do you mean by an Arc? Could you explain in more detail? By Arc do you mean indirect fire (I.E. over the hexes instead of through them)?

-M

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Wed, 06/22/2005 - 11:52
#9
Anonymous
Line-of-sight issues on hex maps

Shrike wrote:
Hey there, if you're doing hexes why not go the simple route have a firing arc instead of LOS? In the rules show where each arc is and then just give modifiers for the to hit roll for obstacles. A small woods adds +1, heavy +2.... put a limit on how many mods can be added until you lose the ability to fire. This is basically what was done for the Battletech hex map game and I never saw any problems with it... I've seen other hex games that have used it too...

Shrike

You would still have to show line of sight, so you can use the modifiers.

If this is on a grid, let the grid show the range, and use a string rubberband detect line of sight.

Firing arcs need line of sight too BTW. If tactical position is critical, and there can be obstacles to shooting, then you have to have line of sight.

C.

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Wed, 06/22/2005 - 12:02
#10
Shrike
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Joined: 08/26/2010
Line-of-sight issues on hex maps

Ok, sorry about being vague, I forget that just b/c I played battletech forever that some folks don't know it. =) Easier to show than to explain... so...

you just extend that out as far as you want the range to go using the "center" or unit hex as the starting point. Anything in that "arc" is seen or in the LOS unless too many obstacles are in the way to obscure it.

Shrike

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Wed, 06/22/2005 - 14:03
#11
OutsideLime
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Joined: 12/31/1969
Line-of-sight issues on hex maps

So much to consider, thanks... some points:

The arc-of-fire diagram I understand fine, but don't make use if it since units in my game do not face in any specific direction and thus have a constant 360º sphere of fire. (A level of detail specifically abandoned in order to smooth the combat mechanic and trim the rules)

Weapons with vertically-arcing trajectories e.g. artillery, grenade launchers, howitzers, etc., are collectively called Lobbers and are dealt with simply; no map obstacle interferes with a lobber. It can hit any target in its range. So no issue there.

My issue is specifically with directional weapon attacks (lasers being the best example) and how to determine whether obstacles that are partially in the way of those attacks serve to block the attack.

Check the diagram:

I am A, firing a laser with unlimited range.
I cannot hit W, because it is clearly directly behind an obstacle.
I can hit X, because it is in a straight line.
I can hit Y, because even though it's off the 6-point hex axis, there are no obstacles that would give the defender any reason to argue the clarity of the attack path.
But Z... Z is a problem. Is Z defended by that obstacle? You could draw a line that blocks the attack, or a line that doesn't. What is the rule here?

What do you guys think??

~Josh

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Wed, 06/22/2005 - 14:23
#12
DSfan
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Joined: 12/31/1969
Line-of-sight issues on hex maps

Hello OutsideLime,

Why don't you just use the same way that HeroScape does Line Of Sight? By this I mean the player might have to get down and look towards the targeted figure. The player would look at the targeted figure like he was his own robot.

That might not make sense so here is the way HeroScape describes Line Of Sight:

HeroScape Master Rulebook wrote:
To attack a targeted figure, your figure must be able to "see" it from it's location. Unlike Range, the [L.O.S] is an imaginary straight line between you and the targeted figure; it has nothing to do with the spaces on the battlefield. If the targeted figure is (for example) behind a ruin or a cliff, so that your figure can't "take aim" at it, then no attack is possible.

To determine if there is a clear [L.O.S], check the Target Point (the green dot on your figures Army Card) and the Hit Zone (the red area on the targeted figures Army Card). Then get behind your figure and look to see if its Target Point can "see" any part of the targeted figures Hit Zone. If so, there is a clear line of sight.

It's simple enough and hopefully will end your L.O.S problem.

If that doesnt work you can always use a laser pointer!

Good Luck,
-Justin

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Wed, 06/22/2005 - 14:41
#13
OutsideLime
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Joined: 12/31/1969
Line-of-sight issues on hex maps

You're probably right... I've been trying to figure some explanation that will allow a player to easily calculate legal LOS in a hex-system without using a mechanical device like a ruler, string, or even a laser pointer.

It may just be impossible to do in an effective and streamlined way.

SO

I see myself with 3 options;

Forget the realism approach, and stick with the six-point legal LOS rule. Even Y on the above diagram would be an illegal target. It's a GAME, and games have RULES, so that's OK. (I mean, chess is a battle simulator... why can't pawns take a step backwards?... because they CAN'T, it's the RULE.)

OR

Break down and use a straightedge to determine LOS. Decide on the legality... Research tells me that some standard methods are
A) if a line can run from anywhere in your space to anywhere in your target space w/o encountering an obstacle, it's legal.
B) if a line can run from the CENTRE of your space to anywhere in your target's space w/o encountering an obstacle, it's legal.
C) if a line can be run from the CENTRE of your space to the CENTRE of your target space w/o encountering an obstacle, it's legal.
Playtesting and philosophy specific to the game (do I want more attacks to be able to hit, or more attacks to be able to be dodged) will decide which method is best....

OR

Just keep thinking, baby.
Keep. Thinking.

~Josh

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Wed, 06/22/2005 - 14:58
#14
phpbbadmin
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Joined: 04/23/2013
Line-of-sight issues on hex maps

OutsideLime wrote:

I am A, firing a laser with unlimited range.
I cannot hit W, because it is clearly directly behind an obstacle.
I can hit X, because it is in a straight line.
I can hit Y, because even though it's off the 6-point hex axis, there are no obstacles that would give the defender any reason to argue the clarity of the attack path.
But Z... Z is a problem. Is Z defended by that obstacle? You could draw a line that blocks the attack, or a line that doesn't. What is the rule here?

What do you guys think??

~Josh

Usually the rule is you need to be able to draw a straight line to the center of the shooting hex to the center of the target hex. If this line goes the through covering hex, then LOS is blocked. Another method says that if you can draw a straight line from any corner of the shooting hex to any corner of the target hex without it being blocked by a covering hex, then LOS is available.

Here's another option though. Count the shortest distance between the two hexes. Now trace every path from the shooter to the target using this shortest distance. For each of these paths that go through the covering hex, give the shooter some sort of penalty to hit. So in your example, you can trace three paths from the shooter to the target; one is blocked and two are 'free'. Depending upon the ratio of blocked to free, you could levy some penalty on the shooter.

Just some ideas.
-Darke

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Wed, 06/22/2005 - 15:30
#15
OutsideLime
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Joined: 12/31/1969
Line-of-sight issues on hex maps

Quote:
Here's another option though. Count the shortest distance between the two hexes. Now trace every path from the shooter to the target using this shortest distance. For each of these paths that go through the covering hex, give the shooter some sort of penalty to hit. So in your example, you can trace three paths from the shooter to the target; one is blocked and two are 'free'. Depending upon the ratio of blocked to free, you could levy some penalty on the shooter.

This is something more along the lines of what I am interested in, and I have thought of it before. However:

even in my simple diagram, where the combatants are a mere 5 spaces away, there are no fewer than SIX "shortest route" options that will take the attack through the obstacle, and FOUR that are free. It works out to a simple 3:2 ratio, but as range increases, so does the complexity, not to mention the difficulty and time-wastage of counting all the different possible routes and being sure that you've got them all...

....but I like your style....

~Josh

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Wed, 06/22/2005 - 15:54
#16
Shrike
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Joined: 08/26/2010
Line-of-sight issues on hex maps

Hate to say it, but I think the center to center fo the hexes has almost go tto be the easiest / quickest thing for you. guess I missed the whole 360 degree thing earlier.

Shrike

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Wed, 06/22/2005 - 17:43
#17
larienna
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Joined: 07/28/2008
Line-of-sight issues on hex maps

When I played "battle master" the rule for the canon was "select any of the shortest distance between 2 points", no need to calculate any ratio. If the player can use a path to its advantage, then so be it. Still, it must always be the shortest path.

Calculating partial cover can complex. You could maybe use partial cover for obstacle in Hex around the attacker and/or around the defender but ignore the ones in the middle of the path. OR you could say that each time the line of sight move on an hex adjacent to an obstacle Hex, you get an additional penalty. So firering along a wall will give you a large amound of penalty.

If you use a ruler, I suggest middle to middle hex since border to border hex give a too high attack range.

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Wed, 06/22/2005 - 18:53
#18
dete
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Joined: 12/31/1969
Line-of-sight issues on hex maps

Ok you don't want to use ruler,

and the second pic you showed with all those lines
doesn't really make sense because of the clear shot that wasn't
straight. (LOS to Y.)

So according to Darke there are 2 possibilities:

center to center then yes it is blocked
and off center to off center then no it isn't blocked.

Now I'd say it's up to the gun.
Laser Sniper rifle, nope you can't hide from it.
Laser pistol, with this clumsy weapon yes your safe.

-dete

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Wed, 06/22/2005 - 23:23
#19
FastLearner
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Joined: 12/31/1969
Line-of-sight issues on hex maps

I like the Heroscape system for it, too. Pick a spot on the "looker" to be its "eyes." Determine on the target what is enough of a hit (like the end of a gun or a sword or something might not qualify, but all of the "body" would). Move around a look from the eyes to the targetable body. Can you see it? Great, you can hit it. Then count hexes.

-- Matthew

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Thu, 06/23/2005 - 20:43
#20
Nando
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Joined: 07/22/2008
Nandoscoping!

OK. Here is my submission for a solution. I'm cleverly calling it Nandoscoping as if I were the first to think of it. Like that's possible in this hobby. Here goes:

This is an algorithm method based on the path from the shooter to the obstacle. If there is no obstacle, it doesn't matter.

1) Find the shortest, least-kinky path from the shooter to the obstacle. Least-kinky means the fewest number of times you have to change directions to connect one face of the shooter hex to one face of the obstacle hex. This seems to be 1 most of the time.

2) Where that path connects to the obstacle, shift one side over (on the obstacle) and repeat the path. This part is hard to explain, but really simple in practice.

3) Repeat the path out as far as needed. The extended path indicates which hexes are "in sight" -- the closest aim you can take to the obstacle and still hit targets beyond it.

Below are pictures to illustrate. The Blue hex is the shooter. The Dark Red hex is the obstacle. The Dark Green hex is the mirrored position of the shooter (beyond the obstacle). The Light Green/Yellow hexes are "out of sight". The Light Red hexes are "in sight". Pink hexes are obviously in sight, but not used in the scoping algorithm.



And lastly, as a psuedo application of the algorithm (you have to assume at least one hex path to start the pattern), there's "peeking":

(The Yellow hexes were an experiment with "partially sighted" hexes. They appear adjacent to sighted hexes when the target distance beyond the obstacle exceeds the shooter's distance from the obstacle.)

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Thu, 06/23/2005 - 21:12
#21
comport9
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Joined: 12/31/1969
Line-of-sight issues on hex maps

Use an L shaped "stick" with one end really long. Design the board so that the short end can "plug in" to the center of each hex. Then, when the stick is inserted it can spiral around. Players could then judge LOS by looking atop the stick. :)

This may be too complicated. But it works. lol.

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Fri, 06/24/2005 - 13:51
#22
OutsideLime
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Joined: 12/31/1969
Line-of-sight issues on hex maps

Nando:

Wow, dude.

Wow.

That's basically exactly what I was interested in.

Of course, now that you've explained it, I see that there's absolutely no way that I can include it in my game. It works, but I can't ask my players to stop the action of chucking laser beams at each other and start counting off hex patterns, especially once more than one obstacle is involved in confirming or denying LOS.

It's a great idea, and it's what I asked for, but it's a clunkifier.

I think that I will stick with the 6-point firing system that I've got in place now. It's a suspension of disbelief that these mighty robots with astounding technology are limited to attacking in 60º increments, but gameplay is smooth and there's not much room for error... and players are suspending plenty of disbelief already just by PLAYING a game featuring mighty robots with astounding technology... :)

Thanks,

~Josh

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