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Calculating averages for DSI

posted Jul 20, 2015 21:47:39 by Matthew Hoeveler
So the average on 1d6 is 3.5, which is helpful information when scaling/comparing things. Calculating averages on DSI is above my paygrade. How do you read DSI in terms of average damage and likelyhood of rolling DSIs?

"If math were easy, it would be your Mom."
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9 replies
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Matthew Hoeveler said Jul 20, 2015 21:50:18
To further illustrate, it seems logical to me that it is safe to assume that you will get 1DSI for every 6 dice in the roll, and further, you are statistically likely to get a 1 and a 2, so for 6DSI, I presume 3 damage and 1 triggering DSI. Is that reasonable?
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Volontius Vortia said Jul 20, 2015 22:12:43
That's how it seems to break down to me as well. I've already houseruled away nearly the entire DS die mechanic - it's ridiculously cumbersome for what it accomplishes. The sheer number of dice that are being rolled for such a small amount of damage and a virtually guaranteed triggering of a DSI icon effect just isn't worth buying, carrying around, or rolling and counting each time. Straight #d6+modifiers for damage with DSI effects as auto 1+momentum is far less annoying and more intuitive.
[Last edited Jul 20, 2015 23:40:14]
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ChristofferLundberg said Jul 21, 2015 09:50:42
I think the whole DS mechanic is brilliant!
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Matthew Hoeveler said Jul 21, 2015 11:38:06
I agree, Chris. My try-hard inner math nerd so rarely has a reason to exist, and DSI seems to be a good one.
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Nathan.Dowdell said Jul 21, 2015 11:59:10
Functionally, each [DS] is worth 0.5 mean damage by itself. For weapons with the Vicious X quality, this adds 0.166 per point of Vicious - so Vicious 1 means the die is worth 0.667 damage, Vicious 2 means the die is worth 0.833 damage, and Vicious 3 means each die is worth 1 damage.

The average isn't the only matter, though - each DS added increases the maximum damage more than it increases the average (though Vicious qualities less than 3 don't increase the maximum, only the average). Each [DS] may only be worth 0.5 damage on average, but they have a maximum of 2, so the peak damage for the attack goes up faster the more dice are involved.

The other significant immediate-damage DSI effect is Spread, but that's a little harder to account for (the damage it inflicts is proportionate to damage inflicted, but it's a separate hit so it's affected separately by Soak, making it less effective against high armour targets).

The use of DSI was designed to produce outcomes that are not reliant purely on skill (skill-based effects are triggered by Momentum); a character's skill shouldn't be the determining factor of everything.
Game Development - 2D20 System
System Design - Star Trek Adventures

Rules questions and playtest feedback to nathan@modiphius.com
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Nicholas Simpson said Jul 21, 2015 15:00:15
As a note, when calculating results for spread, keep in mind that each hit on a DSI for spread is one less die that could add to the actual damage roll. Basically, for all the results on the curve with below average results for damage, the effect that spread will have is reduced (or vice-versa for higher damage). Basically, I'm a little unsure on whether you can apply the independently calculated die average of .5 to the calculations for spread. It's already obvious that the effects of spread aren't going to be linearly increasing for each die you add because if you only have 1 [DS] and roll a DSI on it, it will add 0 damage. Of course, you also have the base damage to account for, which will change the effects of spread. So, calculating spread will basically be a different value for each individual weapon. It's a really hard one to account for.

Quick question: if a weapon has multiple qualities, do all of them activate from a single DSI, or does the player have to choose one to activate?
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Nathan.Dowdell said Jul 21, 2015 16:00:38
Multiple qualities will all trigger for each DSI rolled - weapons with large numbers of qualities can be very powerful. So, a single DSI from a shotgun causes both Spread 1 and Knockdown to trigger at once.

Needless to say, this makes Spread X and Vicious X on the same weapon a particularly nasty combination, as each DSI is both increasing the damage and hitting multiple locations, rather than one or the other as is normally the case for Spread.
Game Development - 2D20 System
System Design - Star Trek Adventures

Rules questions and playtest feedback to nathan@modiphius.com
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Volontius Vortia said Jul 22, 2015 13:32:18
Hey, Nathan! I'm curious - what was the rational behind creating the DS dice with 50% null results? It just seems like making them 1-4, DS & 2 x DS would have provided exactly the same results with half the dice and much reduced chance of a completely ineffective attack.
[Last edited Jul 22, 2015 16:29:18]
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Nathan.Dowdell said Jul 22, 2015 14:47:41
That element was part of the system before I joined the design team - I don't know the answer to that (I came on board as a writer around the time of the v0.5 beta; anything prior to that is before my time).
Game Development - 2D20 System
System Design - Star Trek Adventures

Rules questions and playtest feedback to nathan@modiphius.com
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