Greetings, I have been keeping a list of basic questions as I go and I wanted to post the first few, so here goes!

1. Does firing a ranged attack spell (say Eldritch Blast) or firing a ranged weapon in general through a square that has an ally on it come with disadvantage to avoid hitting that ally? And if so, can a hero pull a move like dropping prone to "shoot between my friend's legs" as this came up in a recent session!
2. Say the party is in combat, and one hero has a familiar, and they send that familiar into another room away form the rest of the party to scout ahead while the battle rages. The familiar discovers something (say additional bad guys in this other location) and dutifully relays this info back to their master. Can that hero tell the rest of the party about it anytime or do they have to wait until their turn to warn their friends more foes may be on the way?
3. If a hero is on any given square, can they attack a diagonal square?

Thanks, I'm sure I'll be back with more as I continue to run games.

1. idk

2. Talking is a free action so yes

3.  Yes

Lyxen’s response.

Though I’ll say for #2 it’s up to you and personally I don’t think it’s too unreasonable to allow them to speak freely or perhaps consume their reaction to convey a simple message out of turn. But I think communicating is meant to be done on your turn.

1 - There are rules you can use like cover, but it slows the game a bit. So I don't apply any penalty to firing into combat. 

2 - Speaking doesn't take time unless it's longer than a few sentences. I would have the PC wait until their turn but telling the party the information does not take an action.

3 - You can attack any square touching your square even if it is only the corner. I prefer hexes but whatever.

A lot of this stuff is DM fiat since fudging things in favor of the players here really wouldn't affect the game balance a whole lot.

A lot of times when firing at targets right next to an ally, cover rules come into play. One of the cool things about this is that with the Sharpshooter feat, they ignore cover... so that character could easily fire into melee combat without any trouble.

It probably wouldn't be unreasonable to consider talking like a free reaction. Like, if there's time for an opportunity attack against a passing enemy, why wouldn't there be time for a quick sentence or two? It's just not common that this kind of situation would come up, since it's normally hard to uncover useful new information when it's not your turn.

1. No. A 5' square on a grid takes up a volume of 125 cu ft. A human takes up roughly 2.5 cu ft. The vast majority of the 5' wide by 5' long by 5' high grid square your token occupies is empty air. There is virtually no chance someone is going to hit you while aiming at a target past your square. You have to remember that a 5' grid square is occupied entirely by a person, not because that's all the humans (or elves, or whatever) that fit in there, but because in combat, that individual is assumed to be in "control" of that space. During the battle, throughout the time that is not your initiative to do something, it is assumed you are making small moves (ducking, shifting, squatting, etc.) as part of the general combat. Don't confuse the graphical representation of pieces on a gameboard with a "space filling" model of beings that are 125 cubic feet.

2. This is up to the DM. I allow conversation among the PCs without restriction, but I come from the old Champions tradition in which talking takes no combat time. If they want to call for a parley with an enemy during combat, that must be done on their turn, because it says so in the PHB.

3. Yes.

Quote from BioWizard >>

1. No. A 5' square on a grid takes up a volume of 125 cu ft. A human takes up roughly 2.5 cu ft. The vast majority of the 5' wide by 5' long by 5' high grid square your token occupies is empty air. There is virtually no chance someone is going to hit you while aiming at a target past your square. You have to remember that a 5' grid square is occupied entirely by a person, not because that's all the humans (or elves, or whatever) that fit in there, but because in combat, that individual is assumed to be in "control" of that space. During the battle, throughout the time that is not your initiative to do something, it is assumed you are making small moves (ducking, shifting, squatting, etc.) as part of the general combat. Don't confuse the graphical representation of pieces on a gameboard with a "space filling" model of beings that are 125 cubic feet.

 Except by RAW, a creature between you and the target DOES impose a penalty, half cover.

A target has half cover if an obstacle blocks at least half of its body. The obstacle might be a low wall, a large piece of furniture, a narrow tree trunk, or a creature, whether that creature is an enemy or a friend.

Even in your example, the two foes are constantly moving, so trying to shoot past your ally who is moving around a lot, rather than standing stationary while you shoot past them, is going to impose some sort of penalty to your aim.

if an obstacle blocks at least half of its body.

It does not say that any creature in a square between you and the target automatically blocks half its body.  It says that IF such a creature does, then there is cover.

That is up to GM interpretation. My interpretation would be "no."

Quote from evlruzai >>

Greetings, I have been keeping a list of basic questions as I go and I wanted to post the first few, so here goes!

1. Does firing a ranged attack spell (say Eldritch Blast) or firing a ranged weapon in general through a square that has an ally on it come with disadvantage to avoid hitting that ally? And if so, can a hero pull a move like dropping prone to "shoot between my friend's legs" as this came up in a recent session!
2. Say the party is in combat, and one hero has a familiar, and they send that familiar into another room away form the rest of the party to scout ahead while the battle rages. The familiar discovers something (say additional bad guys in this other location) and dutifully relays this info back to their master. Can that hero tell the rest of the party about it anytime or do they have to wait until their turn to warn their friends more foes may be on the way?
3. If a hero is on any given square, can they attack a diagonal square?

Thanks, I'm sure I'll be back with more as I continue to run games.

 1. You can shoot through allies without penalty in the rules Read as Written. However, I impose a 2 point AC bonus to creatures that are behind one intervening creature. This is not to represent hitting the creature in the way, but rather the difficulty of the shot. Remember that creatures are not standing still at the end of their turn, they are ducking, weaving, fighting, and location on a gaming tile board is just approximation.

2. Once in combat, players should only communicate on their turns, and have no more than 6 seconds to do so (the length of their turn).

3. Yes. We play that you can move up, down, left and right, and once per 30 feet you can move one diagonal. This is to prevent moving 6 diagonals, which is far more than 30 feet on a 5ft per square board.

Quote from BioWizard >>

if an obstacle blocks at least half of its body.

It does not say that any creature in a square between you and the target automatically blocks half its body.  It says that IF such a creature does, then there is cover.

That is up to GM interpretation. My interpretation would be "no."

Ruling is completely up to you. However, comparing the volume of a human to the volume of a grid square to determine obstruction is pretty misleading. Anyone shooting through a square is concerned with cross-sectional area and not volume. 

A grid square has a cross sectional area of 25 sq ft. A 6 foot tall person wearing armor and carrying weapons could have a cross sectional area on the order of 9-12 sq feet (if you include the gaps between their legs and arms since shooting through those might be tough. In either case, even a stationary creature could block as much as 50% of the view through the square. If you add to this that both the target and the obstruction are moving around, swinging weapons, moving in and out, ducking and dodging then it becomes more difficult to hit a target on the other side of an ally.

Either way, it is not unreasonable to apply a +2 AC cover for firing through a square containing a creature ... certainly not as unreasonable as your volume comparison would appear to make it.

 P.S. To the OP.

Quote from evlruzai >>

Greetings, I have been keeping a list of basic questions as I go and I wanted to post the first few, so here goes!

1. Does firing a ranged attack spell (say Eldritch Blast) or firing a ranged weapon in general through a square that has an ally on it come with disadvantage to avoid hitting that ally? And if so, can a hero pull a move like dropping prone to "shoot between my friend's legs" as this came up in a recent session!
2. Say the party is in combat, and one hero has a familiar, and they send that familiar into another room away form the rest of the party to scout ahead while the battle rages. The familiar discovers something (say additional bad guys in this other location) and dutifully relays this info back to their master. Can that hero tell the rest of the party about it anytime or do they have to wait until their turn to warn their friends more foes may be on the way?
3. If a hero is on any given square, can they attack a diagonal square?

Thanks, I'm sure I'll be back with more as I continue to run games.

 1. Firing through a square containing another creature to hit a different target could give the target half cover. It is up to the DM and if the situation applies they get +2 to AC.

"A target with half cover has a +2 bonus to AC and dexterity saving throws. A target has half cover if an obstacle blocks at least half of its body. The obstacle might be a low wall, a large piece of furniture, a narrow tree trunk, or a creature, whether that creature is an enemy or a friend."

It is a DM call during play as to whether a creature between you and the target will give that target half cover. I usually rule that it does.

2.The player can communicate telepathically with the familiar within 100'. If it is farther away than that then there is no communication. A familiar has the stat block of the respective beast. They aren't very intelligent unless it is one of the special chain pact warlock familiars. They likely can't count, they may not be able to identify creature types and calling them by name is not something a familiar can likely do. A familiar might report a bunch of creatures with arms and legs ... but the player may need to interact with the familiar to determine whether they are kobolds, goblins, orcs or humans for example. This is all very much within how the DM chooses to run familiars but except for the intelligent ones they aren't usually automated independent scouting machines. The player can use an action to see through the senses of a familiar within 100' for a round but they are blind and deaf while doing so.

Could a player receive a message from a familiar during combat? Yes.

The DM determines the nature of the information received depending on how they run familiars.

The player can pass that information along. Some DMs limit players to talking only on their own turn for table reasons. Others allow players to speak at any time. Personally, if I was DM and passing information to a player via a familiar then I would rule that they could pass the information along (as long as it fits in a sentence or two) when they receive it since the characters CAN speak at any time (AND I decided to give the character the information at that point in time) ... characters are certainly not limited by turns that are supposed to be happening simultaneously. The turn structure is a game mechanic, not role playing, so I allow folks to talk at any time as long as it isn't disruptive.

3. If you are playing on a square grid then a character can attack any of the 8 adjacent squares (direct or diagonally adjacent). In addition, it only costs 5' of movement to move to any of the 8 squares unless you are using the variant rule that costs 5', 10' alternating for each diagonal move.

Personally, I like hexes for resolving combat but squares do a much better job of conforming to most buildings and structures so I tend to use those more often.

Quote from Lyxen >>

 

We don't play on grids anymore, but when we did , we apply the 3(.5) way of counting squares (that is diagonal squares count 2 every second one) rather than the stupid 4e counting of diagonals the same as across.

So if you end up moving 12 squares horizontally and 4 squares vertically, this makes a distance of 14 squares. It's not that hard to do and it's a bit less suspension-of-disbelief breaking.

 

  Is why hexes are superior!  =)