Barter is not generally accessible to the construction set. There is precious little that can be done to affect it because the functionality is in the game code. Barter is a function of the relative mercantile skills, the merchant's current disposition, and the haggle percentage.
The dialogue presented during barter is set on the service tab of a quest. Below are the game settings that control the formulas for bartering prices.
- fBarterBuyBase
- fBarterBuyMult
- fBarterDispBase
- fBarterDispositionMod
- fBarterHaggleBase
- fBarterHaggleCurve
- fBarterHaggleDispMult
- fBarterHaggleMax
- fBarterSellBase
- fBarterSellMult
Barter Formulas.
The formula used to check if a trade will be accepted by the merchant depending on the position of the slider is:
Value = fBarterHaggleDispMult * floor(fActorLuckSkillMult * (Disposition - 10) / 4) + (100 + min(PlayerSkill + fActorLuckSkillMult * (PlayerLuck - 50), 100) - min(MerchantSkill + fActorLuckSkillMult * (MerchantLuck - 50), 100)) / (10 - (SliderPosition * fBarterHaggleBase))
- SliderPosition is a value between 0 and 40 (fBarterHaggleMax) and represents the position in which the slider is located.
- If the value returned by the formula is greater than or equal to 0, the trade will be accepted by the merchant.
- Note that sometimes the result of the formula may give 0 (arithmetically) and therefore the trade should be accepted but it is not. This is because of floating-point errors. The handling of these errors can be done but that would over complicate the representation of the formula on this page.
- Editor's note: it has yet to be found if and where fBarterHaggleCurve fits into the above formula.
Alternatively, if you wish to know the best slider position you can use:
BestSliderPosition = floor(((fBarterHaggleDispMult * floor(fActorLuckSkillMult * (Disposition - 10) / 4) + (100 + min(PlayerSkill + fActorLuckSkillMult * (PlayerLuck - 50),100) - min(MerchantSkill + fActorLuckSkillMult * (MerchantLuck - 50),100)) /10) ^fBarterHaggleCurve) / fBarterHaggleBase)
To change the slider position through script, use SetMenuFloatValue with the default path for the slider value being; "Negotiate_Background\Negotiate_Scroll\Horizontal_Scroll_Marker\_Value_Scrolled_To".
Example: SetMenuFloatValue "Negotiate_Background\Negotiate_Scroll\Horizontal_Scroll_Marker\_Value_Scrolled_To" 1025 SliderPositionVar