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So with the confirmation of all direct fire blast weapons being Scatter die + 2d6 - BS of firer, and all barrage being Scatter die + 2d6. I started thinking of the implications to the usual big boys of the template world : railheads, russes, basilisk.

Working the mathematical probability of these scenarios is entirely possible, but I felt it would be easier to just have a spreadsheet calculate 10,000 shots. Here are my quick findings.

Two scenarios: one is that the original target is still under the center hole of the template. The other scenario is that the shot drifts, but the original target is still under part of the template.

All examples use a 1" diameter model for the target.

So:
Direct hit: % of shots that the target model remained under the center hole of the template.
Average drift: Number of inches the shot drifted on average (when it drifted at all)
Cover hit: % of shots that covered the target model at all. Basically the direct hit % + the % of shots that drifted less than the radius of the template + the radius of the target (I assume here that the exact distance is still a hit, the user will fudge it!)

For real math nerds, put a little ~ in front of all these numbers. I rounded rather willy nilly.

BS4, 5" Blast (ex. Railhead, Monolith, Demolisher, Fire Prism solo)
Direct hit: 44%
Average drift: 3.7"
Cover hit: 72%

BS3, 5" Blast (ex. Leman Russ, Direct fire Basilisk, Demolition charge, Gunfex Barbed Strangler)
Direct hit: 39%
Average drift: 4.3"
Cover hit: 61%

BS2, 5" Blast (ex. Battlewagon Killkannon, BigMek Shock attack gun, Elite Carnifex Barbed Strangler)
Direct hit: 35%
Average drift: 5.1"
Cover hit: 51%

Indirect 5" Blast (ex. Basilisk, Airburst fragmentation projector, Whirlwind Missile)
Direct hit: 33%
Average drift : 7"
Cover hit: 39%

BS5 3" Blast (ex. Exarch Missile launcher, Holy orb of Antioch - "3 must be the number counted")
Direct hit: 52%
Average drift: 3.1"
Cover hit: 72%

BS4 3" Blast (ex. Plasma cannons, Wraithlord EML, Disentegrators)
Direct hit: 44%
Average drift : 3.7"
Cover hit: 61%

BS3 3" Blast (ex. Warrior Deathspitters, Zoanthrope warp blast, IG Missile launcher, Guardian Missile launcher)
Direct hit: 38%
Average drift: 4.3"
Cover hit: 52%

BS2 3" Blast (ex. Battlewagon mounted Kannon?)
Direct hit: 35%
Average drift: 5.1"
Cover hit: 44%

Indirect 3" Blast (ex. Mortar, Lobba, D-Cannon)
Direct hit: 33%
Average Drift: 7"
Cover hit: 35%

More factors come into play here:
Partial hits are 100% now instead of 50%
Weapons that used to poof on a miss, now drift and could still catch some baddies

The overall accuracy of blast weapons has taken a large hit in this edition (especially indirect, wtf!). Whether the above factors still keep them viable will remain to be seen.

Moz wrote:
More factors come into play here:
Partial hits are 100% now instead of 50%
Weapons that used to poof on a miss, now drift and could still catch some baddies

Sorry, but I think these "other factors" are going to be much more important than your mathhammer. Both of these seem to be serious anti-infantry blast buffs that more than make up for any supposed nerfs on the scatter side.

Much harder to work out mathematically, but I agree to an extent.

Auto partials are not as big of a deal as people make it out to be though. Previously a normal 5" template hit would catch say 3 & 4 partials against a spread out force with a few ranks. That's 5 total with old rules, 7 with new. Big woop.

So on a 5" blast hit, against say a squad of 30 boyz. Depending on formation we have:

Minimum current = 1 & 1 partial (average 1.5) (Minimum is a single file line of boyz spaced 2" apart)
Maximum current = 13 & 17 partial (average 21) (Maximum is 30 boyz barely fitting on a single 5" plate)

Minimum 5th = 2
Maximum 5th = 30

Most shots will be somewhere in-between and definitely falling towards the minimum. These are gains yes, but hardly enormous. I think another factor that is going to drag blast weapons down is the reduction in blocking terrain. Previously I would pile models together to huddle behind terrain to hide from firelanes, or to keep my heavy weapons near their supporting models to prevent them from being sniped, or to get half the unit in that area terrain without getting any of them behind it, or to have majority of the unit within the objective area.

All of these reasons are gone, and in fact the only reasons left I can find for bunching your models together would be lack of room (orks/guard/nids).

It's hard to quantify any of these statements, but my gut feeling is an overall reduction in effectiveness is what we're looking at (though only dramatic in certain circumstances - indirect and BS2 shooters).

First off, your rounding error is pretty significant, mostly on BS4 though. For BS4 scatter

You will see a hit on scatter dice 1/3 of the time. You will also see 0" scatter 1/6 of the time (-4 from results 1/1, 1/2, 2/1, 2/2, 3/1, 1/3 are all 0" so 6/36 or 1/6). 1/3 + 1/6 = 50%. Pretty significant difference from 44%.

Also with the above in mind, the average scatter for BS4 is much less then 3.7. It is actually closer to 3.1", with 3" being the most common result (eg, 7 on a 2d6).

I'd also pose that a 1" diameter as the size of the target is much too small. Most units will not be that compact, infact most units that'd you'd want to target will be atleast the size of the a small blast--making 1" scatter a decent result in and of itself. With even larger units (which will be very popular in 5ed), even the most common 3" scatter would be pretty insignificant. 3" scatter on a 1-2" spaced 30 man ork or gaunts unit will still cover a ton of models if placed in the middle of the unit (and could likely scatter onto another unit if you are facing a true horde army).

This also brings up an interesting question in 5ed: Is it better to spread out or bunch up against a blast template? If you spread out, you are more likely to get hit, if you bunch up, those hits will hurt but with cover maybe not so much. I think this would need to be decided on a case by case and army to army basis but it is something ti think about.

Overall I think driect fire bS4 and BS3 large blasts are about the same as last edition asfar as chance of truely missing a large target and with no partials is a bit of a boost. And ord that is BS4 or BS3 is pretty much a wash, slighty worse scatter but better chance of kills due to no partials.

After that I agree with you about the effectiveness going down, with orks ord shooting and indirect for all taking a notable hit. I had hopped they'd include some sort of spotter rule for indirect so that BS could be used if a spotter was in LOS of the target.

However, how often will you have to fire indirect in 5ed?

winterman wrote:First off, your rounding error is pretty significant, mostly on BS4 though. For BS4 scatter

You will see a hit on scatter dice 1/3 of the time. You will also see 0" scatter 1/6 of the time (-4 from results 1/1, 1/2, 2/1, 2/2, 3/1, 1/3 are all 0" so 6/36 or 1/6). 1/3 + 1/6 = 50%. Pretty significant difference from 44%.

Also with the above in mind, the average scatter for BS4 is much less then 3.7. It is actually closer to 3.1", with 3" being the most common result (eg, 7 on a 2d6).

You cannot add the drift number directly to the hit number like that. The drift only comes into play on the shots that miss. So the exact number is:
Hit 1/3 results
Of the 2/3 results that miss, 1/6 will still hit
1/3 + 2/3(1/6) = .44

Same error for the Average drift distance. It only comes into play when it's not a hit.

I didn't do the math for any of these either, just running 10,000 trials gives pretty accurate results. It's entirely possible that I did a formula wrong somewhere, but at least in these 2 cases they match the mathematical expectation.

winterman wrote:
I'd also pose that a 1" diameter as the size of the target is much too small.

I was just treating the target as a single model for these tests. Much easier to be precise that way, though it would be cool to add formation stats into this. It's not at all impossible to take these trials and apply them to a map with models on it. I agree that this is a current weakness of the model.

Good point about the reduction in indirect at all in 5th.

You cannot add the drift number directly to the hit number like that. The drift only comes into play on the shots that miss

Whoops, yeah big mistake on my part there. Had a spreadsheet at home with it figured right, shoulda waited till I was there to post. It did seem off when I did it here at work. Sorry about that.

I didn't do the math for any of these either, just running 10,000 trials gives pretty accurate results. It's entirely possible that I did a formula wrong somewhere, but at least in these 2 cases they match the mathematical expectation.

Ok that makes sense and yeah your average drift is definitely the expected result for the 66% scatter.

I was just treating the target as a single model for these tests. Much easier to be precise that way, though it would be cool to add formation stats into this. It's not at all impossible to take these trials and apply them to a map with models on it. I agree that this is a current weakness of the model.

I think you could very easily get some interesting results by figuring what the circular foot print for 5, 10, 20 and 30 model units with spacing at 0, 1 and 2". You wouldn't get results of how many models under a template (without using some kind of x/y plot) but you could still get a feel for effectiveness for different scatters. Could prove useful with only a bit of tweaking of your iterations.

Good point about the reduction in indirect at all in 5th.

At least I got something right.

I play Imperial Guard so I wanted to see how good/bad the Leman Russ and Bassilisk got in 5th edition with the change in scatter rules. First here are the raw numbers (note "<=" means less than or equal to):


4th Edition Stationary Deviation (1d6)
Roll: Chance
<= 1: 16.7%
<= 2: 33.3%
<= 3: 50.0%
<= 4: 66.7%
<= 5: 83.3%
<= 6: 100%

4th Edition Moving Deviation (2d6 take the highest)
All Roll Result Combinations
1: 1-1
2: 1-2, 2-1, 2-2,
3: 1-3, 2-3, 3-3, 3-2, 3-1
4: 1-4, 2-4, 3-4, 4-4, 4-3, 4-2, 4-1
5: 1-5, 2-5, 3-5, 4-5, 5-5, 5-4, 5-3, 5-2, 5-1
6: 1-6, 2-6, 3-6, 4-6, 5-6, 6-6, 6-5, 6-4, 6-3, 6-2, 6-1

Distance:Chance
<= 1: 2.7%
<= 2: 11.1%
<= 3: 25.0%
<= 4: 44.4%
<= 5: 69.4%
<= 6: 100%

5th Edition Stationary or Moving Direct Shot(2d6 - Ballistic Skill)
All Roll Result Combinations
2: 1-1
3: 1-2, 2-1
4: 1-3, 2-2, 3-1
5: 1-4, 2-3, 3-2, 4-1
6: 1-5, 2-4, 3-3, 4-2, 5-1
7: 1-6, 2-5, 3-4, 4-3, 5-2, 6-1
8: 2-6, 3-5, 4-4, 5-3, 6-2
9: 3-6, 4-5, 5-4, 6-3
10: 4-6, 5-5, 6-4,
11: 5-6, 6-5
12: 6-6

Distance:Chance (Ballistic Skill = 3)
<=-1: 2.7%
<= 0: 8.3%
<= 1: 16.67%
<= 2: 27.7%
<= 3: 41.67%
<= 4: 58.3%
<= 5: 72.2%
<= 6: 83.3%
<= 7: 91.67%
<= 8: 97.2%
<= 9: 100%

Indirect Distance
<= 2: 2.7%
<= 3: 8.3%
<= 4: 16.67%
<= 5: 27.7%
<= 6: 41.67%
<= 7: 58.3%
<= 8: 72.2%
<= 9: 83.3%
<= 10: 91.67%
<= 11: 97.2%
<= 12: 100%

What I would consider a "good" shot would be one that either hits or drifts three inches or less.
4th Ed Leman Russ "good" shot stationary: 33% (hit) + [66.7% * 50%] = 66.4%%
4th Ed Leman Russ "good" shot moving: 33% (hit) + [66.7% * 25%] = 49.7%
5th Ed Leman Russ "good" shot: 33% (hit) + [66.7% * 41.67%] = 60.8%

4th Ed Bassilisk Indirect "good" shot: 33% (hit) + [66.7% * 25%] = 49.7%
5th Ed Bassilisk Indirect "good" shot: 33% (hit) + [66.7% * 8.3%] = 38.5%

Based on the data it looks like a Leman Russ gets a "good" shot a little less frequently when stationary in 5th, but a lot more frequently when moving. I would consider this a plus.

On the flip side, an indirect firing Bassilisk gets a "good" shot a lot less frequently in 5th than in 4th. In addition the average scatter distance is a whoping seven inches!!

With the addition of True Line of Sight, the loss of Area terrain, and now unacceptable scatter of indirect shots, does the Bassie become obsolete? Would it not be better to simply take another Leman Russ?

winterman wrote:However, how often will you have to fire indirect in 5ed?

Anytime you don't want to give your target a 4+ cover save?

Basilisks will continue to fire indirectly.

Kadun wrote:
Based on the data it looks like a Leman Russ gets a "good" shot a little less frequently when stationary in 5th, but a lot more frequently when moving. I would consider this a plus.

On the flip side, an indirect firing Bassilisk gets a "good" shot a lot less frequently in 5th than in 4th. In addition the average scatter distance is a whoping seven inches!!

With the addition of True Line of Sight, the loss of Area terrain, and now unacceptable scatter of indirect shots, does the Bassie become obsolete? Would it not be better to simply take another Leman Russ?

My initial thinking is "No," for the same reason I give winterman - if HALF of your direct-fire ordnance wounds are negated by 4+ cover saves, there are still serious advantages to indirect fire, even wildly inaccurate indirect fire.

(But the REAL winner of 5th ed is the Hellhound - it doesn't care about the new cover save rules in the slightest.)

Janthkin wrote:

winterman wrote:However, how often will you have to fire indirect in 5ed?

Anytime you don't want to give your target a 4+ cover save?

Basilisks will continue to fire indirectly.

if HALF of your direct-fire ordnance wounds are negated by 4+ cover saves, there are still serious advantages to indirect fire, even wildly inaccurate indirect fire.

That is a great point that I had overlooked. Even from personal experience I can recall catching many units without cover because of an indirect shot.

Damn you for making me rethink my list again!