   Simple LOS rules for a board game
  I'm working on a board game concept I'm calling "An Hour to Kill", which is basically a turn-based deathmatch set in a mansion. One of the key gameplay mechanics is that each weapon can make either a "bold" attack or a "stealthy" attack, with the stealthy ones much more likely to work. The idea is that if you can get into range of your target without them seeing you, and you haven't made any noise recently, then you can make a stealthy attack. Otherwise, they see/hear you coming and you have to make a bold one. There are also cards for things like canceling a murder attempt you can see, stealing credit for a kill you can see, and so on.What I'm wondering is, how do I set up reasonable rules for determining if player A can see player B? These rules should be: * Reasonably accurate, in that players should be able to quickly say "Yes, I can see that space, but this other space is blocked from view", * Constrained, so that it is still possible to sneak up on targets, and * Simple, since gameplay is meant to be fast and simple. Here is a sample map. I haven't playtested at all, so that's just meant to be an example, but it should give you some idea of what I'm planning -- a bunch of rooms connected by narrow doorways, with the occasional hallway and a few blocks that you can see past but can't walk through. And yes, I'm aware that the "secret laBORatory" is not example very secret. It's a very silly game. One of the weapons is a lawn gnome. As a general rule, I'm assuming that every player, once they finish moving, picks a direction to face in. They can't see anything behind them, or on the same row/column as them, but otherwise have 180° peripheral vision. Thus, to attack someone with their back to a wall, you'd have to sneak up along the wall. That in mind, here's a couple of rules I've considered: * Draw a line from any point in player A's space to any point in player B's space. If the line passes through an obstruction, then they can't see each other. This is simple but somewhat time-consuming to check, and it makes the game feel a bit too geeky (like checking lines of fire with a laser pointer in WH40k, for example).  * Draw a horizontal line across the player's orientation. The player can see all those spaces. Then draw lines out from those spaces along the player's orientation, out until you hit an obstruction. Those spaces can also be seen. For example:This is still pretty simple, but it obviously has some holes. * Like the above, but allow one tile of "bleed" into open spaces from spaces you can see, as long as they don't double-back towards the player (which would let you see around corners):Better, but we've added a weird little exception, and it still doesn't deal well with players who are standing in front of a doorway looking into the next room over. So, any better ideas?   
  Weird little exception aside, the system you described seems pretty good. Can you give a clearer example of what you mean by someone "standing in front of a doorway looking into the next room over"? As you have it, the system is still simple enough that it will rapidly become intuitive and automatic to use.I suspect that the larger issue is going to be having visibility be really strategically significant. Even though the characters can't "see", the players controlling them can see the whole board, and will act on that knowledge. It will be almost impossible to sneak up on someone. When a player spots someone else's piece moving towards them, they will orient their piece toward them, spoiling the surprise. If you force all players into close quarters, you may alleviate the problem of "quick, turn toward the guy who's coming", since everyone is already basically within striking distance. But then, everyone's within striking distance, so there may just be an indiscriminate kill-fest while the ranks are thinned out to a manageable density.No matter how you do it, with a simple system such as this, the last two or three characters will almost certainly come down to a face to face fight, with no stealth. It may just come down to rolling dice, which is probably not your aim.You need a way to control what areas a player can bring into their visibility, perhaps limitations on where you can turn the piece. There also probably needs to be another layer of depth in your game world.Anyway, if you can work this stuff out, it sounds like it would be a fun game. I wish you luck!   ;  Here's an example of looking through a doorway:It seems like the player should be able to see more to the sides. I guess it's not a huge issue though.Controlling the ability for players to control what their characters can see is definitely going to be a key point for the gameplay here. The main trick will be coming up with a system that's plausible but also doesn't make it trivial for characters to see every attack coming. Say...what about lightswitches for each room? Rooms start off dark, which limits your sight range drastically. If you step on a lightswitch then you can turn the lights on, which lets you see further, but someone could sneak up on you and turn the lights off too. If you put a lightswitch in each doorway (which can control the lights in both rooms the doorway opens onto), then there's only a couple of rooms where you can effectively turtle...and a little reworking of the map should fix those up.I'll note for the record that death is no big deal -- you keep your hand, and next turn you can re-enter the board from any of the windows or the front door. Kills are points; that's all.   ;  Warhammer 40k was not intended to be grid based, but it had two LOS rule sets you might be interested in.  The first was base to base.  If the viewer can draw a straight line from any point of your models base to the base of the enemy, without crossing over terrain of sufficient height (every bit of terrain had a height value, and every model had a height - if the terrain was higher than or equal to, the model could be obscured by it) then the viewer has line of sight.  In a turn based game, starting out of line of sight and ending out of line of sight, but passing through line of sight may be hand waved away by simply saying that they rolled, waited until the viewer was glancing away, or just got lucky.  In this way, you need only measure before and after a move, or even just after.A string, ruler, stick, or any instrument might be used for measuring this "line" of sight.The other system was True Line of Sight, which, as the name implies, means that you shine a laser from any point of the viewer model and try to touch any point on the enemy model.  If the laser can hit it, then it can see it.  This requires very sophisticated terrain, though, and isn't advised for something like a flat surfaced board game.  The previous works, however.The grid based system may throw a wrench into this, but it may not.  You can modify the first example and say, rather than base to base, it's center of tile to center of tile, and use the same calculation.  Play test every possible scenario, every means of "cheating the system" and every annoying loop-hole and see if it's tolerable.  Play testing is the best way to make a fun game, but make sure to play test with different audiences (and just observe them playing, if you can, so that your own bias doesn't come into play).Edit: Hah!  How did I miss your mention of WH40k?  It was quite clear.  Well, sorry about that waste of time, but perhaps I can still be helpful.First, I wouldn't worry about your game being "geeky" because it's a board game and "geeks" as you call them are probably your primary audience.  Board games are not generally satisfying for "cool" kids (though I use these distinctions lightly, as they're ultimately meaningless).  Thus, use whatever mechanic is most fun for your game.  Play test everything, and see what comes up with the most interesting result.Second, try D&D's line of site rules.  They use a stairstep cone - that is, you can see the tile that is the door, and in the next row 3 tiles, in the next row 5 tiles, ect ect.  This models how your arc of site tends to open up the further out you go (this is actually what the center-to-center method does, but it's less accurate).[Edited by - Zouflain on August 3, 2009 2:27:22 AM];  Challenging the player to draw a straight line between any point of the tiles of interest is logically correct, fair and not difficult. If the board isn't too large, a simple ruler works perfectly.The example in the third figure, on the other hand, is very arbitrary and I don't see players remembering it. Zouflain mentions a "stairstep cone"; it would work if the player is on doorway squares, but it becomes fuzzy if obstacles are further out.The examples of the first two figures meet the same fate: not all rooms are star-shaped polygons from the location of the player. Imagine 1-square pillars scattered in a large room.;  The game can, of course, be adapted to not involve situations where the LOS algorithm chosen breaks down. But ideally you should be able to hide behind pillars and so on. I'm leery of the "draw a line" mechanism mainly because I'm worried it'll make the game feel too involved. It's meant to be lighthearted and accessible. But given the lack of worthwhile alternatives thus far, I think I'll give it a shot on the first playtest.   ;  In D&D 4E we use the draw a line method to figure out LOS. If 1 of your corner has a direct line to 1 of their corner, you have LOS. It's fast and can be checked without any complex measurement after a few minutes of doing it. To determine cover, you have to check a few more lines, but the situations are usually the same(someone in doorway, in other room, etc) and we know the results without doing any check. We spend more time invoking various supernatural entities to give us natural 20s than we do checking LOS.   ;  I like the second option.  Drawing lines is too precise for a lighthearted board game, and the bleed through is an extra complication that doesn't add anything except "realism".For the doorways, I think the best option is to make the walls thinner.  For gameplay purposes, have the walls be as wide as the lines dividing tiles (on the board you'll probably want them a bit wider to make them easily distinguishable).Maybe look into Hero Quest.;  If there are cards that effect how you kill people, why not cards that effect vision. Stuff that you play down, and it changes your perception types. So one card would make your vision cone like, one would make it line drawing, one would make it able to see through walls, but in a narrow cone, etc. The default could be some kind of short half circle, with any obstacle blocking it off.   ;  I went ahead and threw together a map that has one-dimensional walls. I don't know if this really solves anything on the LOS issue, but it does look nicer.How about this idea? Each player has a cheat sheet that shows their sight radius, along with a set of sight lines. Like so:Then they can line up the cheat sheet with the board, and if there's a wall blocking one of the lines, then they can't see anything in squares with the same color as the line. Or if the space they're trying to see is outside the cheat sheet, likewise they can't see it (we'll pretend that everyone is badly nearsighted). That would generate this "solution" to the doorway problem:Thoughts?   