I had a situation happen and we weren't sure what the ruling would be. I think it might be a line of sight issue.

I had some troopers lined up against a building. There was an enemy unit on the second floor of the same building near the window. The question was, could the enemy unit on the 2nd floor shoot at the unit that was next to the buildings wall or would the enemy unit on the 2nd floor have to be leaning out the window to shoot at them, reducing their cover? Same would apply if an enemy unit was on top of the building and wanted to fire down on units that were next to the building.

This comes down to line of sight honestly and how the building is built. If the troopers on the second floor were directly above the troopers below and if the troopers below were all lined perfectly against the building, I really doubt the troops on the second floor would have line of sight at all. You take line of sight from where the models are in the poses they are in, not assuming they can lean over the edge of a building. They should be able to, but that's just how the game works i guess

Yeah, take a line from the highest point of the mini and at the centre of it and if it can see any part of the opposing mini it has line of sight. Given the elevated position it's quite possible it could see a bit of base , but you would have to see for yourself at the given time. If the building was in the path from the point (for example if the window height was too low that the top of the mini hits the wall above , then no shot, even though in real life they could kneel to get the shot, for example.

It's like the two posters above say (regarding LoS rules). In SWL you use real line of sight, so you need to check for EVERY mini in your unit if they can see the enemy.

If there are minis in your unit that can't see any enemy at all, then they can't contribute to the attack dice pool.

The minis in your unit that can see the most enemy units dedicate which enemy minis can die from an attack, the rest just needs to see one.

Now for cover: If your leader can see at least one mini, the enemy unit doesn't have cover since he is in base contact with the same terrain piece (the house). BUT (and now it gets complicated) if your leader doesn't see any enemies, but other minis in your unit do, you can shoot the enemy unit but they will have heavy cover. This is because you determine cover from your unit leader, which means if he can't see anyone the enemy is considered in heavy cover.

Summary:

You check LoS from each mini in your unit to determine if they can shoot (contribute to the attack dice pool) and to determine which enemy mini can die (every mini that is seen by at least one trooper in your unit)

Range and cover although is measured with your unit leader. If he can see the enemy and they are not obscured = no cover. If at least 50% of the enemy unit is obscured by an object (measured by a line from the mid of your unit leader base to the mid of every enemy unit base) that gives eligible cover (light or heavy, this is declared before the start of the game) to the enemy unit = light/heavy cover. If your unit leader is in base contact with that object = no cover. If your unit leader can't see the enemy = heavy cover and only the minis that can see the enemy unit can shoot.

The cover rules are the most complicated rules in SWL. Don't worry if they look complicated at start. The more you play the easier it gets. By now I check all of the above in about 10 seconds.