Twin linked?

[amberclad87]

So i've seen some people roll twin linked weapons with two dice and pick the highest. Now i'm no math hammer but it seems to me that you are more likely to hit with 2 dice picking the highest than a simple re-roll. Is there a difference?

[BlackSpike]

There isn't really a difference if it is just for one attack.

2 dice will roll a and b. If 'a' is a hit, that's fine. Take it. If 'a' is not a hit, check dice 'b'.

Other way round, if 'b' is a hit, fine. If not, check 'a'.

Either way, if one or the other or both score a hit, this counts as one hit.

 

For multiple attacks, it does not work.

2 Twin Linked attacks, rolling 4 dice and picking hits gives a higher number of hits than it should.

[Grey Mage]

The dice have no memory my friend, or so they say.

 

The statistical chances are exactly the same between rolling two dice and rerolling one die.

 

It should also be noted that the Core book covers this, and lists it as an available option for dice rolling for exactly this reason.

[Koremu]

It works perfectly fine with single-shot weapons (firing a Twin-Linked Lascannon for example), but the distribution will change dramatically if you use a weapon with multiple shots (such as a Twin-Linked Assault Cannon) and roll all 8 dice at the same time.

 

To get a proper distribution in the latter case you would have to roll each shots worth of Twin-Linked Dice separately - meaning that you would roll a pair of dice four times, which is obviously less efficient than rolling all four shots and then re-rolling failures.

[Frosty the Pyro]

Indeed, in a single shot scenario two dice pick the highest is identical to one die with a reroll. With a multishot weapon you would need a way to differentiate each pair of dice, for example a twin linked heavy bolter, you could have two red die, two blue die, and two white die and take the highest of each color and that would also be identical. If however you rolled 6 die and took the three best that would be wrong as it does increase acuracy. A quick example would be a two shot weapon with 4 dice will provide identicle results most of the time, but if you have two hits and two misses, taking the highest will result in two hits, using a preserved pairs though there is a chance both misses will be in the same pair resulting in one hit and one miss.

 

Edit

here is some quick math asuming 50% hit rate (Bs3)

 

Weapon shots | Twinlinked hits | Take the highest hits | TL/TTH

1 | .75 | .75 |1

2 | 1.5 | 1.625 | 1.083

3 | 2.25 | 2.53 | 1.125

[Reglor]

If you have a weapon with Gets Hot rule the order of the roles is importent. If your first roll is a 2 and a miss and your second roll is a 1, the result is diffrent than a 1 than a 2. In addition if you have a weapon with rending the same thing applies. A roll of 5 than 6 is diffrent than a 6 than 5.

 

So for a single shot weapon if the options are hit or miss, the order of the rolls doesn't matter, but if you have critical hits or critical failures than the order does matter.

[amberclad87]

Awesome! Thanks guys.

[Grey Mage]

On the use of multi-shot weapons, my friends often carry several different colors of dice in their pockets, and thus just pull out what they need- IE green, blue, red and black for an assault cannon.

 

Also quite useful for the special weapons in a squad.

[lord gunthar]

Its the same for using multiples of weapons that are master crafted, eg a squad of hammernator termies with vulkan

[Koremu]

On the use of multi-shot weapons, my friends often carry several different colors of dice in their pockets, and thus just pull out what they need- IE green, blue, red and black for an assault cannon.

 

Also quite useful for the special weapons in a squad.

I have a dice box with 15 Black, 6 Green, 4 Red and 1 White (plus a scatter). The only thing that selection of dice can't handle is a full Assault Squad in CC on the charge, and that's because they have more than 26 Attacks!

[Acebaur]

If you have a weapon with Gets Hot rule the order of the roles is importent. If your first roll is a 2 and a miss and your second roll is a 1, the result is diffrent than a 1 than a 2. In addition if you have a weapon with rending the same thing applies. A roll of 5 than 6 is diffrent than a 6 than 5.

 

So for a single shot weapon if the options are hit or miss, the order of the rolls doesn't matter, but if you have critical hits or critical failures than the order does matter.

 

Rending wouldn't matter in this case because rending is decided on the roll to wound not the roll to hit.

[Reglor]

If you have a weapon with Gets Hot rule the order of the roles is importent. If your first roll is a 2 and a miss and your second roll is a 1, the result is diffrent than a 1 than a 2. In addition if you have a weapon with rending the same thing applies. A roll of 5 than 6 is diffrent than a 6 than 5.

 

So for a single shot weapon if the options are hit or miss, the order of the rolls doesn't matter, but if you have critical hits or critical failures than the order does matter.

 

Rending wouldn't matter in this case because rending is decided on the roll to wound not the roll to hit.

 

I had forgoten that. Call it a wishfull thinking for 4th edition rending. (I miss 4th edition death company that could kill a squad without rolling to wound.) The point still stands even if my example doesn't. If you have a critical hit or miss than the order of the rolls is importent.