Trying to work out the average number of successes for an opposed roll using the following system but can't quite seem to get it to work in Anydice
- Roll (3d6-5)+Stat+Skill+Modifier
- 3 6s = crit, roll 3d6-5 again
- 3 1s = fumble = autofail
- Base difficulty 9, extra success for every 2 over (e.g. 11 is 2 successes), max number of successes = skill+1.
Attack is an opposed roll, no. of successes on attack − no. of successes on defence. So if two average combatants (stat 2, skill 2) are fighting one another, I'm trying to work out the chances of various number of successes occurring.
Edit: Thanks for the help, to try and clarify on crits and fumbles:
A basic roll consists of rolling 3d6, the result of the three dice is totalled, then five is subtracted from that total, then the sum of (Stat+Skill+Modifier) is added.
If the initial 3d6 roll is 1,1,1 then the roll is a fumble. It automatically fails even if the modifier would still result in a 9+ result. In an opposed roll your opponent gains an extra success.
If the initial 3d6 roll is 6,6,6 then the result is totaled and five is subtracted (so it counts as 13) then 3d6 is rolled again, totalled, has five subtracted and is added to the initial total. As long as 6,6,6 keeps getting rolled this process continues. "Exploded" rolls dont count as a fumble even if you roll 1,1,1.
Edit: Thanks for all the help, regarding skill caps and how they interact with crits. Skill caps are the final step in the process, dice are rolled, modifiers applied, the number of successes calculated and then the skill cap is applied. If the roll crits then this final step is excluded e.g. Character with Stat 2, Skill 2, modifier 0:
- Rolls 3d6 - Gets 16
- 16 - 5 - 11
- 11 + Stat (2) + Skill (2) + Modifier (0) - 15
- Calculate successes (15 - 1 for 9, 1 for 11, 1 for 13, 1 for 15) - 4 successes
- Apply skill cap, Skill (2) + 1, so the 4 rolled successes become 3. Thats the final result.
If it critted step five wouldnt have been applied.
Though the criticals are really statistically insignificant, maybe having them trigger on 2d6 or on any triple would have a little more impact.