Reversing Morrowind's formulas

[jvoisin]

A few tips about reversing Morowind's formulas :

• The dedicated wiki page is here. Be careful, not all formulas written here are exacts.
• The dedicated topic on bethsoft forum is here
• The uesp wiki is a great place to find stuffs.
• We can try to contact Hrnchamd and Psyringe, respectively developer and test of the MPC
• We can also try to contact Fliggerty, who might also know a thing or two about formulas
• I don't think it's really relevant, but we can try to contact timeslip too (MGE and many Morrowind's internal related work)
• When trying to get a formula, only change one parameter at a time

If you find something, don't forget to put it here

For contacts, we should coordinate our efforts, in order to avoid spamming : please state here who you are contacting.

[natirips]

A few days in bed (picked up some virus) and so many posts about this.

Anyway, from page 142 (156 physically) of MMM_Manual ( http://min.us/mChxB3o1o ):

In many cases where you see Base and Mult game settings, the formula they're involved in is a standard linear equation in the form y = mx + b, where m is the mult, b is the base, and x is some attribute, skill, or other value.

This may save a little bit of work for someone.

I've uploaded MMM Manual to minus.com (link again: http://min.us/mChxB3o1o ) because this forum says "The file is too big, maximum allowed size is 512 KiB.". Anyway, MMM Manual is free for non-profitable use so it should be okay to use it for OpenMW.

[Sadler]

After few hours of inventing the empiric buy price formula for items:

Code: Select all

Buy_Price = Base_Price * (210 + Merchant_Mercantile - Player_Mercantile - Relation) / 161

Please check this. It seems to be fairly accurate.

[scrawl]

Wow, nice. I will add that right away. Do you have any idea about the chance that the NPC accepts your offer? (if you leave the price at default, they always accept, i think)

[Sadler]

Wow, nice. I will add that right away. Do you have any idea about the chance that the NPC accepts your offer? (if you leave the price at default, they always accept, i think)

It will require much more trade tries for model with strong correlation. If I will have a huge amount of free time I'll do that work .

[Necrod]

After few hours of inventing the empiric buy price formula for items:

Code: Select all

Buy_Price = Base_Price * (210 + Merchant_Mercantile - Player_Mercantile - Relation) / 161

Please check this. It seems to be fairly accurate.

Seems pretty accurate, but shouldn't it involve "luck" as well?

[Sadler]

Seems pretty accurate, but shouldn't it involve "luck" as well?

Oh, maybe. Give me a a few minutes, I'll check this.

[Sadler]

Player-merchant luck difference changes the cost. About 10-15% for luck change from 0 to 100.

We may simply add the correction:

Code: Select all

Buy_Price = 26 - 0.6077*Player_Luck + Base_Price * (210 + Merchant_Mercantile - Player_Mercantile - Relation) / 161

Not so straight as first formula, but must work.

[heilkitty]

I reckon, some of the numbers should be GMSTs and not hardcoded. I don't have access to Morrowind right now, so I can't help with that, but you could use some mod that changes trading significantly (e.g. BTB GI Settings) for reference.

[natirips]

MMM Manual has most (if not all) game settings' default values and descriptions on page 142 (156).