Ok, despite the huge confusion at launch and the still officially-unresolved LoS/cover issues, AND the fact that they seem wonky and counterintuitive at first, they're starting to click for me. My impression is that they are pretty cool and actually very simple once you get used to it.

For the uninitiated, and without getting into every clause in the RRG and Alex Davy's email, it's basically that you check for LoS and then draw a line on the ground to determine cover. If that line crosses any part of a terrain footprint, the defender gets the cover that the terrain inherently grants that unit type. This is done in the pregame "define the battlefield" step.

Yes, this step is vital. Though does get easier if you're using the same terrain pieces game after game.

This means that some of my hills that completely block LoS to minis are only light cover. At first that didn't sit right to me and I blamed the rules. But then I realized this saved me from having to make subjective assessments at the edges of the hill to determine how much of the target was obscured (or getting mad when the tiniest part of a single defender was barely behind the hill, making 50% of the unit). The cover line either crosses through the terrain footprint or it doesn't.

My brain worked on this and realized that while it seemed to me that my 6 troopers, mostly behind a tall rock or hill, should have heavy cover--heck they're hidden behind a giant hill!--the minis also represent a dynamic group of soldiers, not a static group of range targets to be picked off. The rules approximate reality, they don't attempt to simulate it with each step of the attack.

The result of "only" light cover is boosted by the fact that the opponent only has LoS on let's say 2 of my minis in the squad behind my hill. So while their cover is only 1, only 2 of them can suffer wounds, and that's only if they fail to roll blocks after removing a hit. Or if I'm mad that the defender gets heavy cover despite having only half of his troops behind any cover at all, I realize I can still overcome it by rolling crits. Either way, the result is a rule that seems to get it right just about every time by the end of the attack.

I would advise to err on the side of giving less cover to your terrain pieces when defining the battlefield, because it seems more intuitive for troops to be left vulnerable by borderline heavy terrain than to be granted heavy cover for it. Keep in mind you're defining the whole footprint, not just the thickest part. If you're fine with that, like a barricade or blast wall, go for heavy. If it's crates, natural earth landscapes, moisture vaporators, etc--err on the side of light cover.

So with a simple (if counterintuitive) rule we are really free to go nuts with our terrain and we've explicitly been given control via the RRG on how we want to characterize our terrain (with the exception of the 50% suggestion, which isn't even too forceful). Attacks can be measured for range and cover determined in a matter of seconds, speeding up the feel of the game and keeping everyone engaged, ultimately making the game more fun.

Of course I know many will disagree, but I do want to strongly suggest giving the clarified rules a chance. Pay attention to the terrain definition step. And let your mind relax as you measure base to base lines across any part of terrain footprints. It was hard for me too at first, but as title says I'm starting to really dig it.

Very necessary TL;DR:

• Banish from your mind the idea of using Line of Sight to determine how much of a targeted mini is blocked by cover
• Pay close attention to the terrain labeling step
• Err on the side of light cover if not sure whether to label terrain cover as light vs heavy
• Play the rules as written/clarified and enjoy how straightforward attacking becomes

EDIT: some of my examples are incorrect as noted by others in this thread. Specifically that when a mini is not even visible to any of the attackers, it automatically counts as having heavy cover regardless of the cover type granted by the piece of terrain it's obscured by.

I think they missed an opportunity for a more straightforward system that would have simplified both cover and line of sight.

They should have defined the height of all figures. Then as you set up terrain, you can assign terrain a height and cover type, and that height determines cover for units.

So for example you have cover type A (light cover, difficult for troops, passable for ground vehicles, passable for repulsors) up to type E (heavy, impassable for all). Then assign a height (1 to X). A trooper is height 2, an AT-RT 4, T-47 or AT-ST 6, etc. Terrain half your height or greater provides cover; terrain your height or greater blocks line of sight unless it is to a target that has a height greater than the intervening cover (probably with an exception based on base-to-base contact).

Speeder values would have to be doubled, but speeders ignore terrain below their height.

With this system you put a sticker on each terrain (A1, B2, C4, etc) and you immediately know if it slows you, what type of cover, and how it impacts line of sight, and all you need is a base-to-base line.

Yeah, it's more "gamey" than "true line of sight" but would be less ambiguous in play.

Well said. When I watch batreps, I see people get hung up on "can I see 50% of that model peeking over a hill?" If you assign each piece of terrain a level of cover before the game, all you have to ask during an attack is, "does the line of sight cross the terrain or not?" If the answer is yes for at least half the models in the defending unit, then that unit has the level of cover assigned to the terrain.

2 minutes ago, Contrapulator said:

Well said. When I watch batreps, I see people get hung up on "can I see 50% of that model peeking over a hill?" If you assign each piece of terrain a level of cover before the game, all you have to ask during an attack is, "does the line of sight cross the terrain or not?" If the answer is yes for at least half the models in the defending unit, then that unit has the level of cover assigned to the terrain.

Exactly. Instead of getting hung up on how much of a mini you can see, try to justify that the attack being represented is dynamic and chaotic, and go with the simple rule to represent it. I promise it won't break immersion nearly as much as taking 5 minutes to eyeball each mini and haggle about mini volume.

6 minutes ago, Hawkstrike said:

I think they missed an opportunity for a more straightforward system that would have simplified both cover and line of sight.

They should have defined the height of all figures. Then as you set up terrain, you can assign terrain a height and cover type, and that height determines cover for units.

So for example you have cover type A (light cover, difficult for troops, passable for ground vehicles, passable for repulsors) up to type E (heavy, impassable for all). Then assign a height (1 to X). A trooper is height 2, an AT-RT 4, T-47 or AT-ST 6, etc. Terrain half your height or greater provides cover; terrain your height or greater blocks line of sight unless it is to a target that has a height greater than the intervening cover (probably with an exception based on base-to-base contact).

Speeder values would have to be doubled, but speeders ignore terrain below their height.

With this system you put a sticker on each terrain (A1, B2, C4, etc) and you immediately know if it slows you, what type of cover, and how it impacts line of sight, and all you need is a base-to-base line.

Yeah, it's more "gamey" than "true line of sight" but would be less ambiguous in play.

Isn't this exactly how the rules currently are (without the stickers, but the same system)? Their 50% of model height is just a suggestion, but it seems to be the same thing you're saying.

Another way of understanding the rule is that all terrain is area terrain. It's an oversimplification to be sure, as I myself have some complex terrain that I do clarify based on different material and heights. But the idea is that for the purposes of cover, all terrain is area terrain by default. The only mechanical difference is that the height of some pieces of area terrain results in more/less LoS blocking than others.

6 minutes ago, Big Easy said:

Isn't this exactly how the rules currently are (without the stickers, but the same system)? Their 50% of model height is just a suggestion, but it seems to be the same thing you're saying.

To an extent -- but since the heights of units aren't defined, each call is a judgement call, and you have separate measurements for line of sight and cover.

In the system I propose, there's no judgment call and no need to negotiate terrain characteristics before the game, and the cover system and line of sight systems use the same mechanics.

8 minutes ago, Hawkstrike said:

To an extent -- but since the heights of units aren't defined, each call is a judgement call, and you have separate measurements for line of sight and cover.

In the system I propose, there's no judgment call and no need to negotiate terrain characteristics before the game, and the cover system and line of sight systems use the same mechanics.

Good point. I didn't see the part about LoS. I guess it is strange that they went with true LoS, but abstracted cover. Maybe they wanted to split the difference between realism and streamlined rules?

I submit that the variance in height between non-speeder unit types is negligible compared to the subjectivity of the human eye. You should be able to quickly eyeball half-height for any trooper unit. If you can't (like the terrain is exactly 18mm), then you really should err on the side of light cover IMO. The barricades provide plenty of heavy cover.

How you define terrain during pregame setup is just between the players in the game. If you want to break terrain down into classes and put stickers on it, more power to you. As I understand it, your system fits perfectly with the rules.

The "true line of sight" stuff is only about whether a unit can actually see another unit to get a shot off. If your model is hidden from the attacker's point of view, it can't be wounded.

Great summary of the rule clarifications. I was struggling to understand that whole LoS and determining cover rule, but it really does simply boil down to going over what terrain gives what cover, and what units will benefit from that cover.

5 hours ago, Hawkstrike said:

To an extent -- but since the heights of units aren't defined, each call is a judgement call, and you have separate measurements for line of sight and cover.

In the system I propose, there's no judgment call and no need to negotiate terrain characteristics before the game, and the cover system and line of sight systems use the same mechanics.

I like your idea, would work great for homemade boards where the whole thing is basically terrain.

Right now the various clarifications are found here and there on various emails and Facebook groups. I have friends who are finding some of the rules and rule loopholes to be deal breakers. Cover and what we expect it does and doesn't do is really important, nearly every game I have played has the use of cover as one of the biggest factors in a players success of failure.

For example if I am touching a building with my unit leader that building doesn't apply as cover to my target unit on the other side. Perhaps you have to note each wall as being a separate piece of terrain, but very quickly what could have been easy becomes quite complicated.

Also you have to be aware that you can have terrain on top of terrain, so you end up with a building on a hill: So you have to account for, the target being on the hill but behind the building, behind the building and behind the building and the active unit could be behind the building but on the hill or behind the hill and the building. Then we add a second story to the building and out heads explode with the simplicity of it all. Perhaps we agree that we can see an AT-ST over this, and forget the AT-RT or T-47.

It would also be nice to have some clearer rules with area terrain, I like the idea that you can fire into area cover but not through and out the other side. However, my opponent is used to playing you can see through area terrain. So he brings an AT-ST with a mortar launcher. Now at the start of the game I suggest that LOS does not continue through area terrain and he doesn't so we then just dice off to see whose interpretation applies. That is not going to be a pleasant game to play for one of us, not because either of us is terrible but because one of us can not play as expected and the only way to solve the problem is by random chance.

So, yes, the rules do away with those problem discussions during the game. By front ending them to the start and then making over sight an issue. For me most of my opponents have been fantastic here and have found a compromise solution, but my friends who have suffered at the hands of opponents who haven't been as agreeable are again finding the lack of clarity and communication very hard going.

I don't think that's the problem. I think the problem is when the tall units (at-st and speeder) are shooting down at a target. Said target is in the wide open but directly in front of the walkers base is a piece of terrain, granting the squad cover.

52 minutes ago, migs6000 said:

I don't think that's the problem. I think the problem is when the tall units (at-st and speeder) are shooting down at a target. Said target is in the wide open but directly in front of the walkers base is a piece of terrain, granting the squad cover.

That’s not how things work with the clarifications that were sent out by Alex Davey. The squad wouldn’t get cover with the clarified rules.

40 minutes ago, Thoras said:

That’s not how things work with the clarifications that were sent out by Alex Davey. The squad wouldn’t get cover with the clarified rules.

I keep seeing the clarifications referenced, are you able to provide a link?

4 minutes ago, Copes said:

I keep seeing the clarifications referenced, are you able to provide a link?

This thread has a screen shot of one of the emails from him. It’s buried in some other answers, but it matches what several other people got.

Post 3 has the LOS/cover email specifically.

11 hours ago, Big Easy said:

My brain worked on this and realized that while it seemed to me that my 6 troopers, mostly behind a tall rock or hill, should have heavy cover--heck they're hidden behind a giant hill!--the minis also represent a dynamic group of soldiers, not a static group of range targets to be picked off. The rules approximate reality, they don't attempt to simulate it with each step of the attack.

Well said!!

This has been my internal response to a lot of immersion concerns that people have with the rules, I just have not been able to articulate it.

5 hours ago, Amanal said:

Right now the various clarifications are found here and there on various emails and Facebook groups. I have friends who are finding some of the rules and rule loopholes to be deal breakers. Cover and what we expect it does and doesn't do is really important, nearly every game I have played has the use of cover as one of the biggest factors in a players success of failure.

For example if I am touching a building with my unit leader that building doesn't apply as cover to my target unit on the other side. Perhaps you have to note each wall as being a separate piece of terrain, but very quickly what could have been easy becomes quite complicated.

Also you have to be aware that you can have terrain on top of terrain, so you end up with a building on a hill: So you have to account for, the target being on the hill but behind the building, behind the building and behind the building and the active unit could be behind the building but on the hill or behind the hill and the building. Then we add a second story to the building and out heads explode with the simplicity of it all. Perhaps we agree that we can see an AT-ST over this, and forget the AT-RT or T-47.

It would also be nice to have some clearer rules with area terrain, I like the idea that you can fire into area cover but not through and out the other side. However, my opponent is used to playing you can see through area terrain. So he brings an AT-ST with a mortar launcher. Now at the start of the game I suggest that LOS does not continue through area terrain and he doesn't so we then just dice off to see whose interpretation applies. That is not going to be a pleasant game to play for one of us, not because either of us is terrible but because one of us can not play as expected and the only way to solve the problem is by random chance.

So, yes, the rules do away with those problem discussions during the game. By front ending them to the start and then making over sight an issue. For me most of my opponents have been fantastic here and have found a compromise solution, but my friends who have suffered at the hands of opponents who haven't been as agreeable are again finding the lack of clarity and communication very hard going.

Regarding the various clarifications, I am only referring to the RRG and the Davy email. I know there's lots of theoretical rules cases out there being discussed but I wouldn't say any of them are definitive.

I myself have a piece of complex terrain with buildings and natural hills combined. I simply treat it as separate and adjacent pieces of terrain. With heavy cover being the max a unit can receive, it's actually quite simple. Is the unit benefitting from heavy cover? Done. Is it not behind a building but the line crosses any of the natural part of the terrain? Light cover.

Also, as I brought up in my original post, many of these cover cases that seem like problems are handled pretty well by LoS. Perhaps the most difficult case is the rooftop scenario, where we even know how much cover should be given but there is debate about whether it goes both ways. I would argue that the unit that is on top of a building gets cover and the defending unit does not, because all terrain is area terrain by default. The rules say to draw a line on the ground to determine cover, not a 3D line. The attacking unit leader is touching the terrain (by being on top of it) so ignores the cover for the defender. The exception is if there's a barrier-type wall at the edge of the building. I would personally rule that as complex terrain, acting as a second piece of area terrain that your leader would have to be in contact with to ignore.

Finally, in response to your area terrain mortar opponent, Alex Davy clarified in an email that when determining LoS, area terrain height for the entire footprint is either 1) as tall as the tallest tree/obstacle, or 2) infinitely high. You and your opponent decide which of those two options you use, but seeing through it is not an option. Yes, it's "only" an email and not in the rules yet, but rest assured it will be and the awkward roll offs will be a thing of the past.

10 minutes ago, Big Easy said:

Regarding the various clarifications, I am only referring to the RRG and the Davy email. I know there's lots of theoretical rules cases out there being discussed but I wouldn't say any of them are definitive.

I myself have a piece of complex terrain with buildings and natural hills combined. I simply treat it as separate and adjacent pieces of terrain. With heavy cover being the max a unit can receive, it's actually quite simple. Is the unit benefitting from heavy cover? Done. Is it not behind a building but the line crosses any of the natural part of the terrain? Light cover.

Also, as I brought up in my original post, many of these cover cases that seem like problems are handled pretty well by LoS. Perhaps the most difficult case is the rooftop scenario, where we even know how much cover should be given but there is debate about whether it goes both ways. I would argue that the unit that is on top of a building gets cover and the defending unit does not, because all terrain is area terrain by default. The rules say to draw a line on the ground to determine cover, not a 3D line. The attacking unit leader is touching the terrain (by being on top of it) so ignores the cover for the defender. The exception is if there's a barrier-type wall at the edge of the building. I would personally rule that as complex terrain, acting as a second piece of area terrain that your leader would have to be in contact with to ignore.

Having JUST read the Davy email referenced here, the building example makes sense. You check LOS first to determine cover. So if the mini on top of the building can see the defending unit clearly (and likely would be able to see the unit's base due to height) then the drawn line doesn't even matter. You only draw the line if any part of the mini is obscured.

12 hours ago, Big Easy said:

This means that some of my hills that completely block LoS to minis are only light cover.

13 hours ago, Big Easy said:

The result of "only" light cover is boosted by the fact that the opponent only has LoS on let's say 2 of my minis in the squad behind my hill.

If a model is completely out of line of sight, it gets heavy cover - that doesn't change under the email clarifications.

You check line of sight, and any minis that are completely blocked have heavy cover. Any minis that are partially blocked - even to just a little bit of their base - you measure from your unit leader's base to that mini's base, and they have the cover of whatever is provided by whatever that line crosses. So in your example, he two exposed minis would get light cover (what the hill provides), the rest of the squad (out of LoS) gets heavy, and then you take whichever is the majority (ex: 3 in heavy 2 in light = heavy; 1 in heavy 2 in light = light).

That being said:

13 hours ago, Big Easy said:

Ok, despite the huge confusion at launch and the still officially-unresolved LoS/cover issues, AND the fact that they seem wonky and counterintuitive at first, they're starting to click for me. My impression is that they are pretty cool and actually very simple once you get used to it.

I do agree with this, yeah. Once we get it official, I think it'll be a good system.

12 hours ago, Contrapulator said:

The "true line of sight" stuff is only about whether a unit can actually see another unit to get a shot off.

It's for checking obstruction. Then, if a model is obstructed, you check the line from base to base to see if it gets cover. (Or, if it's totally blocked, it gets heavy cover).

It's what prevents a squad from getting cover against an AT-ST from a barricade that they're on the far side of the table from, just because it happens to be in-between.

For reference, the Alex Davy email in question:

Quote

As for cover and line of sight:

The line of sight rules in Legion could certainly use some clarification! We will update the Rules Reference for greater clarity ASAP. but in the meantime I hope I can be of assistance.

I believe the confusion begins on page 8; the "Cover Type" section reads "As a general rule, terrain that blocks line of sight to half or more of a miniature provides cover...'

It's clear to me now that this is not explained well. This rule is meant to help players determine what terrain elements will provide cover before the game begins: to do so, a miniature should be placed directly behind the terrain element. If that miniature is at least 50% covered by the terrain element, that element is capable of providing the miniature with cover during the game. For example. players wish to determine whether a stone wall will provide their vehicles with cover. They place an AT-RT directly behind the wall, note that the wall covers about 80% of the AT-RT. and agree that this wall will provide the AT-RT with cover during the game, if it is obscured by the wall. Because the wall is stone, they agree that the cover it provides is heavy cover. Next. they place an AT-ST behind the stone wall and note that the wall only covers about 30% of the AT-ST. They agree that the wall will provide no cover to the AT-ST. These determinations should be made before the game: players do not have to worry about the 50% rule during the actual game itself.

While we're talking Line of Sight and cover, there are a few other points that come up in the thread you linked to that I believe I can clear up. The Rules Reference as currently written don't adequate explain the process of determining cover. We intend to make the following clarification to the Cover entry on page 22 in the next update:

The first sentence of-1. Determine Number of Obscured Miniatures:" should read (missing sentence in bold): "The player checks line of sight from the attackers unit leader to each mini in the defending unit. If any part of a defending mini, including its base, is blocked by a piece of terrain or another mini, the player then traces an imaginary line from the center of the base of the attacker's unit leader to the center of the base of the defending mini. If the imaginary line crosses either that piece of terrain or the base of the mini that blocked line of sight, that mini is obscured. The player repeats this process for each mini in the defender to determine how many of those minis are obscured.'

What this critical addition to the entry does is prevent immersion-breaking scenarios like a barricade granting cover to a unit of troopers that can clearly be 'seen" across the battlefield by a tall miniature like an AT-ST. Essentially, determining whether a miniature is obscured is a two-step process:

1. Check line of sight: if the mini is behind a piece of terrain but line of sight is not blocked to any part of that mini, the mini is not obscured.
2. Draw an imaginary line from the center of the base of the attacker's unit leader to the center of the base of the defending mini. If the imaginary line crosses either a piece of terrain or another unit's base, that mini is obscured.

If at least half of the defender's minis are obscured, the defender has cover. The type of cover (no cover, light cover, heavy cover) should have been determined for each type of miniature at the start of the game.

Finally. I'll elaborate on the concept of "area' terrain. Area terrain is essentially a fiat template -decorated' with removable terrain elements portraying the type of terrain. The most common type of area terrain is a forest, which is usually represented by a grassy base and a few removable trees In the case of such an area terrain forest. true line of sight should not be used: instead, the entire base should be treated as the border of the terrain, and the terrain should be treated (at the discretion of players) as either having height equal to the tallest tree or as infinitely high. Each individual tree is merely a decorative element and can be removed when moving minis into and through the forest. or when checking line of sight. In this scenario, the forest does not block line of sight and two units on either side of the forest can attack one another. Alternatively, if players wish to represent particularly dense forested areas. a forest can be treated as blocking line of sight entirely when it is between two units. but not blocking line of sight if a unit's leader is within the forest.

Ultimately. the terrain types presented in the Rules Reference are suggestions; players are encouraged to define their own custom terrain as they see fit, even creating rules for elements that are not in the Rules Reference like lava flows or treacherous areas of ice.

I hope this has been helpful! I dumped a lot of info on you at once. so please hit me up with any follow-up questions you have.

Cheers,
Alex Davy
Game Designer
Fantasy Flight Games
[email protected]

50 minutes ago, svelok said:

If a model is completely out of line of sight, it gets heavy cover - that doesn't change under the email clarifications.

It's for checking obstruction. Then, if a model is obstructed, you check the line from base to base to see if it gets cover. (Or, if it's totally blocked, it gets heavy cover).

Oh wow, I completely forgot about this and of course you're right. Regardless of cover type, if a mini is completely obscured, it counts as having heavy cover. So if half or more of your minis are totally obscured behind light cover, they actually have heavy cover (and of course the unseen ones don't take wounds).

That makes the system even better in my opinion, and all the more reason to designate a lot of terrain as light cover even if it's pretty tall.

i much prefer just using LOS for terrain.

Big reason being its not only the easiest to figure out but it also conforms to ALL terrain types and shapes/sizes. The pre-match determinations if it will 50% cover everything is highly situational. What if the model is in a doorway of a wall that normally 100% covers? What if the attacker is at an odd angle on an obtuse piece of terrain, making it more like 30% obscured?

I foresee this "determine 50% cover or not before the match" crap being a massive headache in the future.

3 minutes ago, Vineheart01 said:

i much prefer just using LOS for terrain.

Big reason being its not only the easiest to figure out but it also conforms to ALL terrain types and shapes/sizes. The pre-match determinations if it will 50% cover everything is highly situational. What if the model is in a doorway of a wall that normally 100% covers? What if the attacker is at an odd angle on an obtuse piece of terrain, making it more like 30% obscured?

I foresee this "determine 50% cover or not before the match" crap being a massive headache in the future.

The whole point of Alex's email is that you don't need to worry about how much of the model is obscured during the game. It's either obscured or it isn't. If the wall gives heavy cover and the LOS goes through it, then the model gets heavy cover. If the obtuse terrain gives light cover and the LOS goes through it, then the model gets light cover.

12 minutes ago, Vineheart01 said:

i much prefer just using LOS for terrain.

Big reason being its not only the easiest to figure out but it also conforms to ALL terrain types and shapes/sizes. The pre-match determinations if it will 50% cover everything is highly situational. What if the model is in a doorway of a wall that normally 100% covers? What if the attacker is at an odd angle on an obtuse piece of terrain, making it more like 30% obscured?

I foresee this "determine 50% cover or not before the match" crap being a massive headache in the future.

I hear and understand your concern, but I hope you would give it a chance to see if you hate actually applying the rule or if you just hate the idea of it now.

With the doorway example, if no part of the mini is obscured by anything because of the open doorway, that mini has no cover (despite standing in a building that would provide heavy cover). This was an important part of Alex's rule clarification (also applies to the AT-ST shooting over a barricade at troops across the table--that barricade's cover is ignored because it blocks LoS to no part of any defending mini).

If the attacker is at an odd angle and the mini is only 30% obscured, it doesn't matter. The mini is behind cover. My whole point is that while this may be counterintuitive at that level, it benefits the game overall and removes all this fiddliness from the attack process.

43 minutes ago, Vineheart01 said:

i much prefer just using LOS for terrain.

Big reason being its not only the easiest to figure out but it also conforms to ALL terrain types and shapes/sizes. The pre-match determinations if it will 50% cover everything is highly situational. What if the model is in a doorway of a wall that normally 100% covers? What if the attacker is at an odd angle on an obtuse piece of terrain, making it more like 30% obscured?

I foresee this "determine 50% cover or not before the match" crap being a massive headache in the future.

Actually, no, it's much simpler, you're only complicating it.

The rules clearly state (Page 22, Cover) : From the center of your squad leader's base to the center of each target mini: if there's terrain that blocks that, then the target is obscured:
[Disclaimer: When I say SEE it means "you draw a straight line and there are no bits of terrain in between from an eye in the sky, not from true LoS"
Disclaimer 2: Center of base means center of base: Not 50% of the base or whatever: Really center of the base as RAW]

1) Target is a single model:
1a) You see center of the base from your center of the base: No cover to apply.
1b) You don't see center of the base from your center of the base: best cover that's in the way (predetermined for that unit type) applies.

2) Target is a unit with several models:
2a) You see over half the center of the bases from your center of bases: Apply no cover.
2b) You see less than half the center of the bases from your center of bases:
2b*) More minis in the unit you see are behind light cover than heavy cover: Apply light cover
2b**) Some minis are behind heavy cover or a mix of light and heavy cover but don't follow 2b*) : Apply heavy cover

The % of the mini that's currently obscured doesn't matter: It's the center of base to center of base, then applying cover that's in between. This is why predetermining terrain quality is so important.


IMO the only weakness of the rule in that regard is: What about elevation?
We house-rule it currently.