Roll20 uses cookies to improve your experience on our site. Cookies enable you to enjoy certain features, social sharing functionality, and tailor message and display ads to your interests on our site and others. They also help us understand how our site is being used. By continuing to use our site, you consent to our use of cookies. Update your cookie preferences .
×
Create a free account

Rollable Table and the Bell Curve

1429156038
Tom
Pro
Sheet Author
I'm taking advantage of some unexpected downtime to rebuild some rollable tables for my game. Has anyone got a trick to giving the table a "bell-curve" effect? Is it just a matter of evenly reducing the weight of the result, or is there something more to it? Thanks!
1429156233
Tom
Pro
Sheet Author
Also, has anyone put together a good roll template to clean up table results? As is, they sure eat up a lot of space in the chat window. Anyone care to share?
1429165910
Umbra
Sheet Author
Yeah, adjusting the weight of the result would be the way to go. Use AnyDice or something to find a dice expression of your choice, then use that to find the respective weights for your results. Remember that Roll20 uses integers for the weight, not percentages, so you can't straight-up use the AnyDice values. For example, if you use 3d6, the total number of possible results is 6^3, or 216. The percentage listed for an 11 is 12.50%, so the weight you have to list in the table is 12.50% of 216, or 27.
1429165999

Edited 1429166524
Lithl
Pro
Sheet Author
API Scripter
Yes, to get a bell curve, simply modify the weights on the table. For example, 2d6 forms a bell curve, which could be represented with the following table: Name Weight 2 1 3 2 4 3 5 4 6 5 7 6 8 5 9 4 10 3 11 2 12 1 If there's a specific dice roll bell curve you want to emulate, it can help to list out all the possible results for the roll: Die 1 Die 2 Total 1 1 2 1 2 3 1 3 4 1 4 5 1 5 6 1 6 7 2 1 3 2 2 4 2 3 5 2 4 6 2 5 7 2 6 8 3 1 4 3 2 5 3 3 6 3 4 7 3 5 8 3 6 9 4 1 5 4 2 6 4 3 7 4 4 8 4 5 9 4 6 10 5 1 6 5 2 7 5 3 8 5 4 9 5 5 10 5 6 11 6 1 7 6 2 8 6 3 9 6 4 10 6 5 11 6 6 12 Count the number of times each total appears, and use that for the weight. If there isn't a specific die roll you're emulating, simply make sure the weights are symmetrical. (The number of table items with weight X should be an even number, unless X is the highest weight on the table.)
1429175190
Ziechael
Forum Champion
Sheet Author
API Scripter
I can't add to the math side, well not with any level of accuracy anyway ;) ... but... you can use rollable tables to reflect percentage values (see the wiki, specifically here for details). You can additionally add "weight" to items in two methods; either enter the number of times you want the item be a possible result OR enter a percentage value. When using percentage values, do not place "%" after the number, and the final number of all items that are elements of the table must equal 100.
1429237766
Tom
Pro
Sheet Author
Thanks, guys! That's exactly what I needed to know.
Just to mention, the numbers do NOT have to add up to 100, they will work with any numbers Adding two elements with a weight of 20 and 40, will add up to 60, but the first one will come up 1/3 of the time, and the other 2/3. You can add 10 elements each with a weight of 3000, and they'd come up exactly 1/10. So if you got percentage values, you can use those of course, in that case the result must be 100, otherwise it won't match the % values. That's all.
1429257205
Ziechael
Forum Champion
Sheet Author
API Scripter
Quatar is spot on, i was merely addressing the percentage question, but like he says any ratio that gives the desired effect will do. I tend to default to percentages as it is a very easy way to understand your potential output ;) Happy rolling!