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Drop Chance Clarification

Posted: Tue Dec 10, 2019 5:20 am
by Banker141
Mike Wrote
Droprates work as follows:

For any NPC, there's a list of items that can be dropped (some items can be dropped twice but with different amounts, such as coins). For every entry in this list, there's a certain chance (out of 1000) that it will be dropped on kill. For example, a very rare drop may have a drop chance of 10 (so 10/1000 or 1%).

Whenever the NPC is killed, the server goes over every single entry in the droptable for that NPC and generates a random number between 1 and 1000 (including those 2 numbers). If this number is smaller or equal to the drop chance, the item is dropped with the appropriate amount. In theory, you could kill an NPC and have 10 different items drop in one kill (although this happens very rarely).

If you're wearing a ring of wealth (or have an ex-ex-parrot following you or have one in your inventory), this drop chance is increased by 12%, meaning a 1% drop chance will increase to a 1.12% drop chance, or a 11.2/1000 chance (this is rounded down and becomes 11/1000 or 1.1%).
If there's an event going on, then the drop chances for the NPC('s) involved in the event increase by 20%, so an item with a 1% drop chance now has 1.2% drop chance (12/1000).
If there's an event going on and you wear a RoW/parrot, the drop chance is increased by 20% + 12% = 34%, then a 1% chance becomes a 1.34% chance (13/1000).

The highest extra drop chance anyone could get is during an event, with a RoW/parrot, wearing a whip of fortune and using its spec on the NPC once = 20% + 12% + 14% + 1% = 47%, so a very rare drop of 1% becomes 1.47% or 14/1000. An item with 1.5% chance then becomes 2.205% (or 22/1000) etc.
Source

I was wondering if this is still accurate, Because when this post was made I don't believe there were any Items with a droprate of greater than 1/1000.

Following this logic a dragon war hammer, having a base drop rate of 1/2000 according to the wiki, would have a 0.05% chance to drop each kill. If you use a ring of wealth that drop chance would be 0.05% + 12.0% + 0.17% drop rate. This is over three times as likely and that just doesn't seem plausible.

Another possibility I've considered is making the drop rate 1% before adding ring of wealth bonus, for example:
if 1/2000 = 0.05% Then 20/2000 = 1.00% + 0.12% = 1.12% So if 20/2000 = 1.12% Then 1/2000 = 0.056% Which seems more probable.

Another question does the ROW / Whip of Fortune affect the drop chance on clue caskets, crystal chest, TOB chest etc.

Thank you for your time and dedication to this server that we all love. I hope that the discussion that follows is helpful to my fellow PkHonor players and useful to the community as a whole.

-Banker141

Re: Drop Chance Clarification

Posted: Tue Dec 10, 2019 5:44 am
by Iron adam
The drop multipliers are multiplicative, not additive. Simply multiply the original drop rate by 1.12 to get the new drop rate when wearing a ring of wealth. 1 in 2000 times 1.12 equals 1.12 in 2000 (0.056%). So you can see, your second set of calculations is correct. As for where the drop rate gets rounded off nowadays, idk.

-Iron Adam

Re: Drop Chance Clarification

Posted: Tue Dec 10, 2019 6:18 am
by Monys
Iron adam wrote: Tue Dec 10, 2019 5:44 am The drop multipliers are multiplicative, not additive. Simply multiply the original drop rate by 1.12 to get the new drop rate when wearing a ring of wealth. 1 in 2000 times 1.12 equals 1.12 in 2000 (0.056%). So you can see, your second set of calculations is correct. As for where the drop rate gets rounded off nowadays, idk.

-Iron Adam
This is right everytime, 1.12% of the time! Go Iron aDAM

Re: Drop Chance Clarification

Posted: Fri Dec 13, 2019 10:24 am
by Slap a ho
Ring of wealth is wrong, at least vs. OSRS. It’s probably favorable the way it is though.

On OSRS, ring of wealth only affects RDT, nothing else. On pkh, it affects everything.

Re: Drop Chance Clarification

Posted: Fri Dec 13, 2019 5:21 pm
by Iron adam
Slap a ho wrote: Fri Dec 13, 2019 10:24 am Ring of wealth is wrong, at least vs. OSRS. It’s probably favorable the way it is though.

On OSRS, ring of wealth only affects RDT, nothing else. On pkh, it affects everything.
well we dont even have rdt. we dont have drop tables in general

Re: Drop Chance Clarification

Posted: Fri Dec 13, 2019 6:30 pm
by Rapsey
Yes, this is still the way it works. The only thing that has changed is that internally drop chances are now defined as a x/10000 fraction (rather than x/1000) to enable us to make drops more rare. As Adam pointed out, drop chance multipliers are multiplicative and not additive. That's the only thing in your post which was incorrect.
Banker141 wrote: Tue Dec 10, 2019 5:20 am Another question does the ROW / Whip of Fortune affect the drop chance on clue caskets, crystal chest, TOB chest etc.
AFAIK it should affect them but I'm not sure tbh. Unlike regular monster drops, loot chests are all implemented separately so it's possible there's a chest out there where we forgot to take RoW etc into account. One of the devs should be able to answer that one.

On a random FYI sidenote, our drops list also shows drop chances as percentages if you hover over them (just like the OSRS wiki).

Re: Drop Chance Clarification

Posted: Fri Dec 13, 2019 8:57 pm
by Banker141
Thank you Rapsey! That clears up a lot!