You might remember my monk class for SotU, and it’s weird method of calculating unarmed damage. The problem is the usual: adding two dice gives a bell-curve, and even then, you can’t simulate all intervals that way.
So now I will share my 3 methods of rolling numbers in intervals other than the usual dice allow.
Dividing the number rolled with a different number, the latter of which the maximum rolled number X (ie dX) is divisible by. Round up if you’re using a computer.
d12 / 4 = d3
Rolling two dice, the latter of which deciding if we add the maximum X (ie dX) to the former. Think classic d20 numbered 0-9 twice. You roll a second die to decide if what you rolled is A or 10+A.
d8 & d3 = d24
Probably the simplest and most unlikely method, where we roll a die that is capable of higher numbers than our intended maximum. We simply re-roll any too high numbers. Beware that this method can be re-roll-heavy if the die is far larger than the intended maximum.
d12(11) = d11
Since we’re not adding dice, there is no bell curve, since we’re not multiplying dice, there are no missing numbers.
So with these methods, it should be a cinch to roll the [1 to HD+1] interval for damage.