"Question about die roll modifiers" Topic

I know this question may sound a little odd but I'm wondering what method games and designers use to determine base hit numbers and modifiers.

For example: You are using a 10 sided die, you have a base number to hit of 6 or less. You get a modifier of +3 which would be 30%, I assume. So is the modifier 30% of 6 which would be 1.8 or rounded to 2 so 6+2=8 or would it be 6+3=9 or less?

I know there are some games out there that have some type of historical baseline they use to generate base numbers and modifiers and others are pretty subjective and limited by how many pips on the dice.

Would one method be more accurate than the other or it really does not matter as long as it fits into the entire game design?

Is anyone aware of systems that use an alternative to a basic hit + die roll modifier?

Wolfhag

You are using a 10 sided die, you have a base number to hit of 6 or less. You get a modifier of +3

Is that a modifier on the score rolled on the die or a modifier to the score required?

A modifier on the score rolled on the die means that instead of the range of scores being 1 – 10 it would be 4 – 13. So the modified chance of scoring 6 or less would be 30% (i.e. on modified scores of 4, 5 or 6)

If it is a modifier to the score required then instead of needing 6 or less you would only need 9 or less. The modified chance of scoring 6 or less would be 90%

Quite a difference between the two …

Modifiers, in my experience, are always listed as integers not percentages. +3 means just that: add 3.

All rules are subjective.

I need to ask if the question is based on a set of written rules or in the context of say developing a to hit table for some such set of unwritten rules.

Given a written set of rules using D10 that states you have a base number of 6 or less to hit, but that you get a +3 at say close range then it is +3 and now you need a 9 or less.

If you are asking within the context of designing say a "to hit chart" and you have determined that some such weapon hits on a 6 or less at its mid- range, but at close range the chances of hitting increases by 30% then the +2 number would be appropriate in the development of that chart. An 8 or less reflecting the 30% increase (rounded up of course) in the weapons ability to hit. So charted the weapon would receive a +2 .

If you are asking within the context of designing say a "to hit chart" and you have determined that some such weapon hits on a 6 or less at its mid- range, but at close range the chances of hitting increases by 30% then the +2 number would be appropriate in the development of that chart.

If the mid-range is 6 or less then that is a 60% chance of getting a hit.
If the close range probablity is increased by 30% then that would make it 90%, so you need a +3 modifier on the score to hit.

I agree given that the rules use a 10 sided dice as given in his example and he wants the chart to reflect a 30% increase in the chance to hit.

Yet if he is trying to say that he wants to increase the chance by a value equal to 30% of 6 .30 x 6 = 1.8 (rounded up = 2) 6 + 2 = 8
Such figuring being done prior to ever building a chart.

I was really trying to get at where he was coming from in context of the question. I was not sure if he was just looking at it as a mechanic thing

Yet if he is trying to say that he wants to increase the chance by a value equal to 30% of 6 .

No, he said he wanted a modifier of +3. We have not yet established if that is a modifier to the score rolled or the score required.

The bit about 30% of 6 is as far as I can tell some erroneous maths on the part of the OP.

It would appear from his example that the modifier is to the initial score required. He appears to want a modifier of +3, but it seemed to be unclear to him whether that was a 30% increase or a 30 percentage point increase. It's a 30 percentage point increase.

If he wanted a 30% increase, the initial 60% would become 78%. An increase of 30 percentage points brings the 60% to 90%.

MBY had a chart for just this kind of calculation. Going up a column always increased a chance by X percent.

What is MBY?

"Is anyone aware of systems that use an alternative to a basic hit + die roll modifier?"

There are a variety of systems where you look up a result on a table. One of the most interesting is in Birds of Prey ( link ) . You roll percentile dice, apply any modifiers, and look up the result in a column ( the column is based on how good you are at the task, for instance ) . Cross-index to the side to get the result. The interesting part is that the results form sort of a bell curve, but the modifiers to the dice are linear. As a result, small modifiers do almost nothing to average results, but can have big effects on very good or very bad results.

Piquet/FoB family rules systems use opposed die rolls, with die shifts UP or DOWN form a base due type, ranging D4 – D6 – D8 – D10 – D 12. After D12, one is added to the score for each additional UP, but the top result is still capped at a 12.

Should have been MBT, by Avalon Hill (soon to be published by GMT).

If you started out with a 50% chance to hit each step up the chart was 5 percentage points added while each step down 5 points subtracted. 60% would be 6 points added or subtracted, etc..

Thanks for the feedback guys. I got out my MBT and Panzer charts as suggested. I'm going to be going with column/row modifiers rather than integers as it seems to give a more accurate result and easier to perform for what I'm doing.

emckinney: You are really hardcore if you play Birds of Prey.

Thanks,
Wolfhag