See also the .
These optional rules address where an effect happens, often for determining friendly fire or where an effect actually happened. In general use a die that best maps to the coordinates around the target. These rules will assume a square grid map.
Alex throws a Molotov cocktail at Billie. Alex needs to a throw a DC 15 to get the grenade on target. Typically a critical failure means either a dud or attacking oneself. In this case Alex rolls a 12, a miss, but the Molotov cocktail still travels. Alex rolls a 1d8 => 5 to get the direction and places the landing position of the Molotov 3 (15 - 12) spaces away.
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..................234................
.........A........1B5.X..............
..................876................
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Billie did not enjoy the Molotov cocktail so they shoot back at Alex with a shotgun. Typically we would simply use the AC abraction rules, but in this case, shotguns have a side effect; the buckshot spreads out in a cone. Anyone next to the path of the shot has a chance of getting hit. Alex has an AC of 15, so as long as Billie rolls a 14 (15 - 1) Carol has a chance of getting hit with splash damage, for whatever remains from the potential damage that would have hit Alex. Billie rolls a 15 to hit and a 1d10 => 4 for Alex. Carol has a 10 AC, so Billie hit them also, with a 1d10 with a max potential damage of 6 because 4 of 10 already went to Alex.
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.........A=========B.................
.........C...........................
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Similar to above Splash example, but with another person standing next to Alex.
Similar to above Scatter example, but with an explosive that has a timer and can roll rather than a Molotov which explodes on contact.
Analogous to hitting the broad side of a barn. Even if missing the intended target, surely something or someone suffered the effect, assuming not a critial failure.
.........F...........................
.........E...........................
........GA=========B.................
.........C...........................
.........D...........................