Math-hammering single big blast vs multiple smalls

[minigun762]

Does anyone know a quick/easy way to determine the effectiveness of one big 5" blast vs 2+ 3" ones for various BS values?

 

In particular, I'm trying to determine if a Defiler/Vindicator's large blast @ BS3 will hit more/less targets on average compared to 2 small blasts from a pair of BS4 Obliterators.

[Chengar Qordath]

Math-hammering blast weapons is a very inexact science, since blast weapons are so situational. Depending on how the enemy formation is set up, you could scatter two inches and have your blast rendered useless, or scatter the maximum distance and do more damage than if it had actually been on-target.

[greatcrusade08]

Dont do it, think of the innocent cogitator machines that would have to be sacrificied..

 

logic is no substitute for gut instinct, the $20 gal from last nights arrest told me that one

[Warp Angel]

Effectiveness is directly proportional to the number of models caught by the blast, which is directly proportional to the layout of the target.

 

So let's actually look at the weapons and do some gut checks...

 

1) Obliterator blast templates are S7 AP2 vs. Defiler S8 AP3 and Vindicator S10 AP2

 

2) S8+ allows for instant death to T4 creatures and the Defiler is instant death to T5 creatures. S7 eats Guard and Eldar.

 

3) The surface area covered by two small blasts is less than that of one large blast, so if the models are deep strike concentrated, you'll have a higher upper end of potential wounds with the large blasts against optimally concentrated models

 

4) The distance from center hole to edge on a large blast template allows for greater deviation distance while still allowing hitting of the orignal target. This means that a large blast template is more likely to hit at least one target in a dispersed formation.

 

5) The middle ground is murkier where you've got some dispersion, but not a lot.

 

I think we can summarize that if your only concern is number of potential casualties, the large blast templates can cover more and are more likely to cover some than two small blasts, but might be less optimal in some targetting scenarios.

 

The larger templates in question also have a higher strength potential, making them more effective against targets with multiple wounds.

[LardO'Blood]

It really depends on the situation. I prefer small blasts though because you have a better chance of doing at least ONE casualty.

[pingo]

It really depends on the situation. I prefer small blasts though because you have a better chance of doing at least ONE casualty.

 

Can you explain? Surely you get an even better chance of at least one casualty with a large blast?

[jbarket]

I'm assuming he means multiple shots means you're more likely to score a hit. Otherwise, I don't follow either, heh.

[minigun762]

I think we can summarize that if your only concern is number of potential casualties, the large blast templates can cover more and are more likely to cover some than two small blasts, but might be less optimal in some targetting scenarios.

 

The larger templates in question also have a higher strength potential, making them more effective against targets with multiple wounds.

 

 

Go figure, that was my first reaction as well. I think the sheer size of the larger blast will help cover more guys more frequently even if its less accurate.

[greatcrusade08]

i choose thunderfires every time.. 4 small blasts beats one large and is cheaper than many of the other options too

[Warp Angel]

i choose thunderfires every time.. 4 small blasts beats one large and is cheaper than many of the other options too

 

4 small blasts changes the question though. It can get more potential casualties than the large pie plate. 2 can't.

[mowglie]

Careful!

 

It's not the area of the template that matters, because partial hits still count. You need to add 1" to the diameter of each template to represent the area of the table where a small-base model could be centred and still be hit by the blast.

 

1 Large is still bigger than 2 Small, but not my as much as you might think (1/8th bigger).

[Warp Angel]

Careful!

 

It's not the area of the template that matters, because partial hits still count. You need to add 1" to the diameter of each template to represent the area of the table where a small-base model could be centred and still be hit by the blast.

 

1 Large is still bigger than 2 Small, but not my as much as you might think (1/8th bigger).

 

If you place a 1" base model as a deep strike model, place a ring of 6 around him and a ring of 12 around that, a 5" template can get up to 19 models in a single blast.

 

A well placed small blast will only get the 7 at the center, giving two templates a maximum of 14 models.

 

FOUR well placed small blasts will get as many as 28 models.

 

For less compacted groups of enemy models, the large blast has a greater chance of hitting at least one model (has to have a total deviation of at least 4"), where a small blast has the potential to miss with a deviation as small as 2".

 

Assuming BS 4, the actual math to hit a model with a 1" base is: 1/3 direct hit + (2/3 * 7/12) deviation for large blast = 7 in 9 chance of hitting the original target.

 

Same assumptions: 1/3 direct + (2/3 * 5/18) = 11/27 chance... less than half for hitting the original target.

 

Again, model grouping affects whether or not you hit secondary targets and that's hard to quantify.

[BearersOfSalvation]

You also have to consider how many units it takes to get the small blasts. If you have a dev squad or that leman russ variant with half a dozen plasma cannons, then you can consider them all together. But if you have 5 small blast weapons firing individually, they go off one at a time, so the opponent can choose casualties from the most concentrated part of the squad, making your later blasts less effective, which they can't do against a single large blast.

 

If you're comparing a vindicator with plasma cannon equivalents, there are situations where the S10 + reroll pen help over the S7 also. For regular marines it's a wash, but most multi-wound modles that aren't MCs suffer ID from a vindicator - Thunderwolf cavalry and nob bikers are the two where it really shines. Scattering into vehicles, the 3+D6 from a non-center hit from the small blast is laughable, but 5+D6 can hurt a rhino or chimera (especially from the rear), and a direct hit can crack anything.

[bystrom]

If you're firing S7-S10, AP3/AP2 blast weapons, wouldn't you rather fire against elite squads (which tend to be small)? In which case, the squad probably doesn't consist of 19 models, more likely 10 or less, in which case 2 small blast could be better.

[Warp Angel]

If you're firing S7-S10, AP3/AP2 blast weapons, wouldn't you rather fire against elite squads (which tend to be small)? In which case, the squad probably doesn't consist of 19 models, more likely 10 or less, in which case 2 small blast could be better.

 

Completely dependent on how the enemy deploys. If it's clustered, then the single big is usually better. If it's dispersed as much as possible, the big still gets more. If it's somewhere in the middle, MAYBE 2 smalls is better.

[mowglie]

If you place a 1" base model as a deep strike model, place a ring of 6 around him and a ring of 12 around that, a 5" template can get up to 19 models in a single blast.

 

A well placed small blast will only get the 7 at the center, giving two templates a maximum of 14 models.

 

That is not correct. Even allowing for reasonable spacing between models, a direct hit from the 3" template will clip six models in the second ring for a total of 13.

 

(The 5" template would also theoretically clip 12 models from a third ring of 18 in the unlikely scenario where you faced a sufficiently large and dense unit.)

 

That's a moot point though since you pretty much never get to fire at units of 19+ in deep strike formation.

 

The more important considerations for actual play are:-

 

1) Since squad coherency is 2", your opponent can deploy in such a way as to minimise damage from small blasts. A direct hit from a large blast on an infantry squad with 3+ models will always hit at least three of them.

 

2) Two small blasts from the same attack have a chance let you hit the most crowded part of the unit twice, rather than a larger (probably less crowded) part of the unit once. You can especially see this in practise if you put a squad of 5-7 models in deep strike formation. The large blast can only ever score 5-7 hits, while the small blasts have a chance to score 10-14.

 

It is neither quick nor easy to compare large and small blasts. It depends too much on the board even before you begin to consider that the weapons probably have different S and AP.

[lord gunthar]

So if you used lash of submission on a 30 man ork squad and moved them into perfect deepstrike formation, could you hit everyone with a single demolisher/battlecannon if it doesnt scatter ?

[Hellios]

So if you used lash of submission on a 30 man ork squad and moved them into perfect deepstrike formation, could you hit everyone with a single demolisher/battlecannon if it doesnt scatter ?

I think the squad might be too big... but I could be wrong... I've managed to get 21 hits on a tactical squad with a Tempest launcher that had 3 shots... which is more than a single large blast could have got... but it is very situational... if 3 tactical squads had been with each other then maybe a large blast template could do more.

 

Nice jorb Mowglie (@ Mowglie's post below)

[mowglie]

So if you used lash of submission on a 30 man ork squad and moved them into perfect deepstrike formation, could you hit everyone with a single demolisher/battlecannon if it doesnt scatter ?

 

Best thing to do is try it yourself. Use empty bases if it's too difficult to see with models.

 

Theoretically, yes, a large blast can hit 1 + 6 + 12 + 12 (the six models on the outmost points of the third ring are safe) = 31 models. However, by the time you're getting to the third ring, the template is only slightly over the base. You might have a hard time convincing your opponent.

 

Mocked this up quickly. Might be a bit difficult to see.

 

http://img545.imageshack.us/img545/1414/blasts.jpg

 

Also, unless I'm mistaken, you can put the template with the hole entirely over the base of the target, but not centred over the base of the target. This not only means you might hit more models on a direct hit (depending on the layout of the models on the board), but also if you put the left side of the hole "touching" the left side of the base, then a 2" scatter right will still hit.

 

I hope if people take anything from this thread, they take that it *is* very difficult to compare large and small blasts :)