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View Full Version : Rolling 2D10s instead of a 20



Scowling Dragon
2012-09-02, 02:07 PM
Wouldn't that result in a much better probability curve? So that your mighty archer doesn't miss a barn 1/20 times?

Boci
2012-09-02, 02:08 PM
Wouldn't it be simpler to remove the "natural one always misses rule"? This leads to less critical hits, so whilst it probably benefits players, I'd be against it.

Mark Hall
2012-09-02, 02:10 PM
It does result in a curve, but it also changes some values radically, depending on the system. If you crit on a 20, it goes from 1 in 20 attacks to 1 in 100. Conversely, a crit on 19 is twice as likely... but a crit on 18 is 4 times as likely (if I've done the math right) as a crit on 20.

Yora
2012-09-02, 02:12 PM
1d20 is not a curve. It's perfectly straight 5% for every result.

Here is the curve for 2d10. (http://anydice.com/program/392) Numbers under 6 and over 16 become less common, the numbers from 8 to 14 become more common.

Thespianus
2012-09-02, 04:36 PM
1d20 is not a curve. It's perfectly straight 5% for every result.

A curve can be a straight line. ;)

TuggyNE
2012-09-02, 05:00 PM
If you're going to use a different rolling system, I'd suggest UA's 3d6 bell curve (http://www.d20srd.org/srd/variant/adventuring/bellCurveRolls.htm); it's more detailed and has some interesting analysis.


A curve can be a straight line. ;)

If you're gonna be nitpicky, at least call it a line segment. :smalltongue:

But I'd actually call 2d10 a peak, not so much a curve.

PaintByBlood
2012-09-02, 05:21 PM
If you're going to use a different rolling system, I'd suggest UA's 3d6 bell curve (http://www.d20srd.org/srd/variant/adventuring/bellCurveRolls.htm); it's more detailed and has some interesting analysis.

This. 3d6 makes for a beautiful bell, which is what you really find, 2d10 does not.

The d20 is there to make drastic events much more possible, however, and using either curve lowers the chance of those fun criticals, amazing saves, and other awesomeness much less likely. The d20 makes being amazing just as likely as being average just as likely as screwing up.

Also, isn't a natural 1 as a miss a variant? I haven't played high enough level lately to recall exactly, but I thought natural 1 is only a fail on saves as far as Core is concerned before variants and homebrew.

Hiro Protagonest
2012-09-02, 06:09 PM
Also, isn't a natural 1 as a miss a variant? I haven't played high enough level lately to recall exactly, but I thought natural 1 is only a fail on saves as far as Core is concerned before variants and homebrew.

Errr no. It isn't.

TuggyNE
2012-09-02, 06:10 PM
Also, isn't a natural 1 as a miss a variant? I haven't played high enough level lately to recall exactly, but I thought natural 1 is only a fail on saves as far as Core is concerned before variants and homebrew.

It isn't.
Automatic Misses and Hits
A natural 1 (the d20 comes up 1) on an attack roll is always a miss. A natural 20 (the d20 comes up 20) is always a hit. A natural 20 is also a threat—a possible critical hit.

You might have been thinking of auto-failing skill checks on a 1, which is a houserule (and generally a poor one, IMHO).

PaintByBlood
2012-09-02, 11:49 PM
It isn't.
You might have been thinking of auto-failing skill checks on a 1, which is a houserule (and generally a poor one, IMHO).

That is what I had been thinking of.
Regardless, the d20 still gives an even chance of great things or terrible things, and 2d6 makes a much better curve than 2d10 (and is pretty well supported).

Medic!
2012-09-03, 12:15 AM
There are quite a few rolling variants out there in published sources. The already-mentioned 3d6 bell-curve is a great one, and I'm personally a big fan of the Natural 1 is -10, Natural 20 is +10 style of doing things. I always had a bit of a believability problem with a 15th lvl fighter having a chance to miss a kobold, or said kobold having a chance to lay so much as a scratch on said fighter.

I also always disliked the "All I need to do is roll a 20" mind-set. It led to a lot of questionable activity at our table in the past....especially from the rogue dual-wielding vorpal weapons. "I know I left the party behind, but I'm attacking that ancient red dragon alone anyway...all I have to do is roll a 20 and I've got 4 attacks........."

Aux-Ash
2012-09-03, 01:21 AM
2d10 have it's merits over d20, but whether it is better or not depends on what you seek to achieve. A regular d20 has the drawback that every roll is equally likely, but that is also the beauty of it. Yes, rolling a 1 is equally likely to rolling a 10, but also equally likely to rolling a 20. That means that no matter how external modifiers alter the sum, each roll is equally likely. There's always that chance for the worst and the best roll.

2d10 has an average and it is it you will alter with any external modifiers. Roughly 50 % (44 % to be precise) of the rolls will fall between 9 and 13. 70 % of the rolls between 7 and 15. 90 % between 5 and 17. 98 % between 3 and 19. The only thing any external modifiers will do is push the average up or down, but the really extreme values will still be just as unlikely.

Is it better? Depends on what you seek to do with it. What treshholds do you have in place, how likely a success should be and so on.