Yet another question about disarming

[Estie]

My rogue with 100% disarm chance, both types, tried to disarm a chest protected by multiple traps and set off an explosion.
What exactly does 100% disarm chance mean ?

[PowerDiver]

It means you are a bit better than if you had 95% chance. I know, not helpful. I haven't played for about a year, but I think I remember failing on maybe 20% of the deep chests with multiple traps when disarming was listed as 100%. I decided it was not worth a slot to carry wands or rods, but I also chose not to squelch them either. Put off opening the chest as long as possible and pick up a device if you see one. Also, carry them if by some chance you have a free slot, until you need to drop them.

[Nick]

100% disarm chance means perfect disarm for floor traps.
Disarming skill for a particular trap is base skill (for your race/class) minus trap power. Trap power for a floor trap is DL/5, so that is the skill that is shown on the character screen. Trap power for chest traps can be much higher - in fact it's the sum of the powers of all the trap on the chest, and explosions have power 64. Theoretical maximum is 120
Note also that you get two rolls of 100 vs skill; failing the first means you fail to disarm, failing the second as well means you set off all the traps.

[Estie]

Interesting. I havent played many rogues since the change and my non-rogues always carry a disarming device. I somehow feel it would be shameful for a rogue to do the same.

What is base disarm skill; the way Nick describes it, it looks like a lvl 1 rogue has the same chance to disarm a chest as a lvl 50 rogue ?

In my game, I ended up doing somthing along the lines of PDs suggestion for a while, but eventually I didnt bother and just took the risk of trying to disarm. I had no more failures late in the game, so I was wondering if the chance to disarm chests went up without any change in the display of 100%.

[backwardsEric]

What is base disarm skill; the way Nick describes it, it looks like a lvl 1 rogue has the same chance to disarm a chest as a lvl 50 rogue ?

racial bonus (maximum 15) + 45 + ((20 * character level) / 10) + bonus from dexterity for physical traps (maximum 19) + bonus from intelligence for magical traps (maximum 19)

The racial bonus is from lib/gamedata/p_race.txt. The parameters for the class are from lib/gamedata/class.txt. The tables for bonuses from dexterity and intelligence are adj_dex_dis and adj_int_dis in src/player-calcs.c. A level 50 hobbit rogue could reach 179: 59% chance of disarming the most dangerous chests.

[marcccoss]

Hi,

I think you should A 100% disarm chance means that your rogue should be able to successfully disarm any trap or chest every time they attempt it, without fail. However, if your rogue set off an explosion, it could be due to a game bug or a specific trap mechanic that isn’t covered by the standard disarm chance, such as traps that trigger under certain conditions despite the disarm success rate.

Thanks

[Estie]

racial bonus (maximum 15) + 45 + ((20 * character level) / 10) + bonus from dexterity for physical traps (maximum 19) + bonus from intelligence for magical traps (maximum 19)

The racial bonus is from lib/gamedata/p_race.txt. The parameters for the class are from lib/gamedata/class.txt. The tables for bonuses from dexterity and intelligence are adj_dex_dis and adj_int_dis in src/player-calcs.c. A level 50 hobbit rogue could reach 179: 59% chance of disarming the most dangerous chests.

Thanks for the comprehensive answer. I had been looking through .txt files, but only found trap.txt. 59% is not impressive, so my HE non-50 rogue was lucky to not blow up any more chests. It looks like I am going to want to carry rods even with rogues; what a pity.

[Estie]

Hi,

I think you should A 100% disarm chance means that your rogue should be able to successfully disarm any trap or chest every time they attempt it, without fail. However, if your rogue set off an explosion, it could be due to a game bug or a specific trap mechanic that isn’t covered by the standard disarm chance, such as traps that trigger under certain conditions despite the disarm success rate.

Thanks

The policy has been to make the Angband interface as clear and non-misleading as possible, which is why I didnt expect disarm fails when the chance was listed at 100%. Turns out the display is correct, but only for floor traps. No ingame information for chests, but hey, thats what the forums are for!

[backwardsEric]

59% is not impressive, so my HE non-50 rogue was lucky to not blow up any more chests. It looks like I am going to want to carry rods even with rogues; what a pity.

That 59% chance is to disarm it in one try. As Nick mentioned earlier, triggering the chest trap requires another roll after the disarm failure. The chance to trigger the traps with one disarm try would be 41% * 41% = 16.81%. If your character keeps trying to disarm until successful or the traps are triggered, the cumulative disarm chance would be 59% * (1 + 41% * 59% + (41% * 59%)^2 + ...) = 59% / (1 - 41% * 59%) = 77.83% and the cumulative triggering chance would be 41% * 41% * (1 + 41% * 59% + (41% * 59%)^2 + ...) = 41% * 41% / (1 - 41% * 59%) = 22.17%.

[Nick]

I love it when the answer to a gameplay question involves in infinite series

[Estie]

Thanks again; so thats 1 in 5 of the hardest chests going off on a lvl 50 hobbit rogue. Is drop quality affected by the trap difficulty ? I was under the impression that only chest type determines it, so a locked large steel chest would have the same drop list as a multi trapped one.

[Nick]

Thanks again; so thats 1 in 5 of the hardest chests going off on a lvl 50 hobbit rogue. Is drop quality affected by the trap difficulty ? I was under the impression that only chest type determines it, so a locked large steel chest would have the same drop list as a multi trapped one.

Yes, you've got that right.