I'm having trouble understanding the rules about LOS to (not through) a corner.

If nothing else is blocking, can the same line to the same corner be blocked sometimes and not others depending on where the target is?

Specifically can someone please point me to the rule that blocks the blue LOS line here:

Any help greatly appreciated.

Update:

I contacted FFG and they replied. The idea is that sometimes when you go to a corner where walls meet you have to apply the rules as if you are going through a wall depending on if the target is on the other side of the corner.

In the mean time this is how I understand things:

I think a given corner can both block and not block relative to what is on the target space's edges and relative to whether you are going to or through it. This is what I'll go by for corners, but to be clear I can't get here from the written rules:

1. By default a corner does not block.

2. Going through a corner blocks LOS if the line splits walls and/or blocking terrain edges that meet at that corner so that the walls and/or blocking terrain edges are on both sides of that line.

3. A line to a corner is considered blocked if, when you draw a line from that corner into the target space, the full path goes through a meeting point of two or more wall and/or blocking edges.

Basically:

-Sometimes going to a corner blocks:

-Sometimes going to the same corner does not block:

Because there is a wall both between Luke and the Storm trooper, and all along the top edge of the diagram. So there's no path around the top of that wall like there is the bottom of it. And while both of the bottom two corners for Luke are visible from the storm trooper since they intersect each other it's not valid LOS for an attack.

Thanks. I get most of that.

I'm trying to discern if LOS to that corner is blocked no matter where the target is.

In this example the lines are the same, neither go through blocking terrain, and they both go to the same corner. The thicker lines are walls. The target "T" is the only thing that is in a different place. Are both blocked?

Does it matter where the target is when I draw LOS to that corner? I'm trying to figure out what rule makes a line (that is otherwise unblocked) be blocked when it ends at a corner.

Because there is a wall both between Luke and the Storm trooper, and all along the top edge of the diagram.

But the line never crosses those walls. I understand LOS cannot cross a wall.

I'm confused by your question. I think you are following this paragraph from the rules reference:

" Walls only block line of sight along an entire edge of a space.

Yeah that's the crux of my question. Why can I draw LOS to the one on the right but not the one on the left? The line does not go through a wall. By my understanding I'm drawing LOS to that corner regardless of a target. I don't think the rules cover this.

So the same line to the same corner both can and cannot have LOS, which is very confusing.

So in this if the thick lines are walls one cannot say if the red line has LOS to that corner?

By my understanding I'm drawing LOS to that corner regardless of a target. I don't think the rules cover this.

You know, I agree with ya.

The issue is at the corner specifically, nothing to do with "through."

If the current reasoning is that you cannot use a corner that has an intersection of walls (or anything else that blocks LOS), than both examples above would be examples of no LOS because every corner has an intersection of walls.

It's silly because the example on the right lacks a wall directly in front of it.

These imaginary yellow lines block line of sight and movement. Here I've illustrated where the line of sight is being drawn from. The red arcs indicate which square is 'visible' when line of sight is drawn to it. In the lower corner, the wall does not block line of sight at all. There are no additional edges to block line of sight.

In the upper target corner, you can draw line of sight to the corner of the square on the right, but in order to get to the square on the left, you have to go through the yellow line.

Remember how line of sight is drawn:

Basically, I think that contrary to mathematics, in this game the upper right corner of left-target's space and the upper left corner of right-target's space are not the same. You can get to one without crossing a wall, but not the other. However, this is never explicitly stated. So yeah, I think there is a rule missing here that would clear this situation up.

I don't understand why they made it two distinct lines for line of sight. Add that after you check if you can see both corners, you have to see if anything obstructs a line drawn to any point of the edge delimited by those two points. That seems like it would clear up a lot of odd situations. Like this one where the attacker A can see the target T even though the target is trying to hide: ... (although maybe that's intentional)

That's about as good as I can get with this one. If that doesn't satisfy you, please submit a rules question to FFG and let us know how they explain it to you.

So in this if the thick lines are walls one cannot say if the red line has LOS to that corner?

But you're not tracing LOS to a corner, simply to a figure. The definition of a wether or not you can see the figure is if you can trace a line between one of your corners to two of their corners. Therefore which square the figure is in matters.

Thanks for the replies. Here's the deal, I don't think there is a clearly written rule that says why the blue line in the original post is blocked. It is not going through any wall. The line to determine LOS stops at the corner and never crosses the wall. I sent a question to FFG becasue although this example is pretty obvious there are more subtle ones I can think of that will come up and might not have clear rules to settle them.

I don't understand why they made it two distinct lines for line of sight. Add that after you check if you can see both corners, you have to see if anything obstructs a line drawn to any point of the edge delimited by those two points. That seems like it would clear up a lot of odd situations. Like this one where the attacker A can see the target T even though the target is trying to hide: ... (although maybe that's intentional)

I agree. From one of the attacker's corners through every point up to and intersecting one side of the target's space would have been so much more clear.

By my understanding I'm drawing LOS to that corner regardless of a target. I don't think the rules cover this.

You know, I agree with ya.

The issue is at the corner specifically, nothing to do with "through."

If the current reasoning is that you cannot use a corner that has an intersection of walls (or anything else that blocks LOS), than both examples above would be examples of no LOS because every corner has an intersection of walls.

It's silly because the example on the right lacks a wall directly in front of it.

Yeah it's the to and not through cases that are rough.

And as far as the intersection of walls that rule seems very unclear to me.

Here the blue line is not blocked. But something tells me it would be if your target were in the "T" space, though I don't think there's a clear rule why one is blocked and the other is not.

Thanks for the replies. Here's the deal, I don't think there is a clearly written rule that says why the blue line in the original post is blocked. It is not going through any wall. The line to determine LOS stops at the corner and never crosses the wall. I sent a question to FFG becasue although this example is pretty obvious there are more subtle ones I can think of that will come up and might not have clear rules to settle them.

But there is a wall. There is a vertical wall separating the square Luke is in and the square immediately to his right.

Thanks for the replies. Here's the deal, I don't think there is a clearly written rule that says why the blue line in the original post is blocked. It is not going through any wall. The line to determine LOS stops at the corner and never crosses the wall. I sent a question to FFG becasue although this example is pretty obvious there are more subtle ones I can think of that will come up and might not have clear rules to settle them.

But there is a wall. There is a vertical wall separating the square Luke is in and the square immediately to his right.

Thanks. I do see that. I guess the next step is what written rule do you use that says the wall above and the wall in front block line of sight to that corner? I'm not trying to be obtuse, I might have missed it, and I'm really looking for that exact text.

I can easily get to that conclusion through common sense, but I am struggling getting there by the RAW.

My point is that depending on how the rule that blocks that blue line is written it might make some other adjudication wonky.

Here's an example of how you could interpret the rules to say that line is blocked. Written rule:

The squares/spaces are not defined by the lines. The squares are what's inside the lines. And since the line does not have zero width the upper right corner of luke's square is not the same corner as the upper left corner of the square to the right. Since the wall does follow the path of the line and is not part of the square, tracing to the top right corner of Luke's square does pass through the wall, tracing to the top left corner of the square to his right does not.

The squares/spaces are not defined by the lines. The squares are what's inside the lines. And since the line does not have zero width the upper right corner of luke's square is not the same corner as the upper left corner of the square to the right. Since the wall does follow the path of the line and is not part of the square, tracing to the top right corner of Luke's square does pass through the wall, tracing to the top left corner of the square to his right does not.

Thanks. I was thinking that too. In fact I got excited when that came to me. This is a lot like what Budgernaut was saying in his excellent post with the illustration.

But notice the lower line to Luke is not blocked (if it weren't for the two lines). If this theory were the case wouldn't you cross the wall line on the way to just inside Luke's lower-left corner?

Also, if all of this is the case they really need to say that a square's corner is not shared with any other square and is in fact just inside the grid lines. None of this is in the rules.

Edit:

I think this one better shows why that's not the case:

Ah, but remember:

I've been thinking about it lately and it's best to think of the squares as separate from each other.

That's what I started thinking too, but it doesn't quite work. You see, the beauty of a grid system is that you don't have to physically draw a line between many of the squares. Instead, you do some quick mental geometry to figure out if you're crossing anything that blocks LoS. That's why they have you drawing corner: it's so simple. By making each square a separate corner, everything becomes off by that fraction of a millimeter. Does it make a difference? I don't know. Maybe.

They really need to make sure they explain every case of line of sight for both firing and for ability effect, it was soo darn confusing in descent, i hope they give us clear rules as to every case in which line of sight is blocked and can be used.

Ah, but remember:

"Line of sight can be traced parallel along a wall (8), blocked

space (9), or door (not pictured)." - 26

So the horizontal line on the bottom would be okay to either corner (Luke's square lower left or Luke's square lower right).

I've been thinking about it lately and it's best to think of the squares as separate from each other.

So about the original problem about the blue line you highlighted, just picture a small gap between Luke's square and the square directly to the right of him and you can visually picture in your head the LOS crossing one yellow line to to get to the other.

I'll even argue that the target in the example below is completely hidden because if you visualize a small gap between the target's square and the square directly below it, you can see in your head the LOS crossing the wall.

And the Target can freely shoot the the attacker because... he is adjacent to the wall and can draw out from there...

errr....

This is frustrating.

I see what you are saying but I get the feeling in this example the rules intend for A to have LOS to T. I think the corner does not block becasue there is no intersection of walls (and in this case I think intersection can means line segments that share the same endpoint. But who knows becasue there is a case of this where a corner does not block).

I really don't think the concept of a corner having 4 points is what they mean or is a good idea. Applying maths to that would get ugly with my skirmish buddies and in tournaments...

I think a given corner can both block and not block relative to what is on the target spaces edges and relative to whether you are going to or through it. This is what I'll go by for corners, but to be clear I can't get here from the written rules:

1. By default a corner does not block.

2. Going through a corner blocks LOS if the line splits walls and/or blocking terrain edges that meet at that corner so that the walls and/or blocking terrain edges are on both sides of that line.

3. A line to a corner is considered blocked if the target and the attacker do not share the same quadrant and two or more wall and/or blocking edges of the target's space meet at that corner.

I've been thinking about it lately and it's best to think of the squares as separate from each other.

That's what I started thinking too, but it doesn't quite work.

It's interesting because under the adjacent heading it states:

To get to the bottom line I'd like to know if these two are blocked or not and what written rules apply:

A is attacker

T is target

Yellow lines are the LOS lines

All terrain is just as seen on the map

I really appreciate anyone's help with this.

Do you consider the Appendix to include "rules as written?" For my part, I consider the appendix to be rules and not just diagrams of rules from the Line of Sight section. To that end, I submit this:

1) When drawing line of sight, we only draw to corners. However, even though we are targeting a corner shared by 4 squares, we are only targeting one of those squares.

Next, you have to consider whether or not that space is "blocked."

They do define Blocked Terrain (p. 8, Learn to Play) specifically as a space with red lines around it. That's how I read that part, though it does say blocked space and not terrain. Also note that 11 is a space of Blocked Terrain.

Here are a few more I'd like to see what people think about.

T: Target

A: Attacker

Red lines are LOS lines

I'm not saying this is sufficient, I'm just giving it as another point of view.

I think we're getting there and thanks for all your points.

I feel like I'm jumping the gun a bit and some of these might not come up. And in the end I can invoke "common sense" but we know that sometimes goes out the window when your opponent is about to roll a nasty attack on you...

I've posted a few specific examples to try to get the conversation away from "theory" and onto the game board. Once I hear what the final word is on these I'm satisfied.