path-of-exile
How does the "Elemental Equilibrium" passive skill work?
For how long is the change in resistance applied to the enemy? How does it affect enemies when you hit them with multiple elements at the same time? Does the penalty stack or stay at 50%)? Also in the case of multiple simultaneous elements, which element is considered "first" to hit? Is "Chaos" damage considered elemental? Does it apply to spells as well as melee and ranged attacks?
There are ways to make small changes to your skill point distributions in the passive skill tree, however the intention is not that you simply 'reset' the skill tree and instead make a new character if you want to make a large quantity of changes. This is detailed on the Path of Exile website:
If you want to adjust your passive build during gameplay, there are Passive Skill Refund points available from quests or relatively rare items in the game that can be found or traded for. Fixing mistakes with a character build or improving small-medium sized aspects is relatively easy, but our intention is that players who want to try substantially divergent character builds are encouraged to play a new character through the game, organically leveling it up rather than just respeccing into it.
You'll get a few respec points from quests which each allow you to remove a single skill point, so you can try out big nodes and undo little mistakes. This doesn't remove the need to plan your skill point distribution ahead and you'll still have to pay attention.
You can refund individual skill points by using Orbs of Regret (purchased from Yeena in Act 2) but if you're level 20 or above it's easier to just make a new character.
It is not possible to completely reset your passive skill tree.
If I understand it properly, I think there's a problem in the question itself. As you said:
The merchants give you Scroll Fragments for white items, so we can sort of divine that that is the base item value. But it doesn't really flow well from there [...]
It doesn't add up, indeed, and you gave the exact reason in your own question:
- Path of Exile has done away with a single unified currency entirely. Exact
- [...] there's no way to tell what anything is worth, or which items are worth more as part of the local economy. More or less correct
Actually, while there isn't any curve to express the value of the items in terms of value, we probably could figure one out based on the difficulty to obtain the item from the vendors.
Scroll Fragment with pretty much any crap item (which are easy to find). Scroll of Wisdom with 5 Scroll Fragments (which are easy to find, but you need 5 of those). Portal Scroll with Scroll Fragments (but you need 15 of those). It's getting harder to obtain, but still feasible.Armorer's Scrap with an piece of armour with a 20% quality, or with several pieces of armor with a total of 40% quality: feasible, but you'll need patience.Chromatic Orb with any item that has 3 sockets of different colors and linked together: you'll have to be very patient to find one of these.Orb of Chance with 2 rare items that share the exact same name: it's getting super hard.With that in mind, the whole currency thing becomes a matter of recipes, and the "value" of each currency item is determined by its difficulty to be "cooked" (let's put it this way) and, therefore, its rarity.
The vendor recipe system allows the player to sell items to any town vendor in exchange for a multitude of currency items and equipment. Each recipe requires semi-specific items or combinations of items be put into the sell window at the same time, and the outcome will change based on any recipes that have been matched.
Source and list of known recipes: http://pathofexile.gamepedia.com/Vendor_recipe_system
The only remaining uncertainty in this system is the drop rate of each currency item (because, of course, it's also possible to obtain them by killing mobs). But I couldn't find any information about it.
The dev diary given by Gnoupi is also an excellent reading: Dev Diary: Rethinking Gold as a Currency.
Best Answer
First off, it applies to all elemental damage whether it's from a spell or attack. The penalties/bonuses do not stack with multiple hits. Chaos is not an element, fire, ice, and lightning are the only elements. The way multiple elements at once work is that the penalty is applied to all the elements you hit with on the previous attack, and the bonus to the ones you didn't hit with on the previous attack. So if you hit with both fire and ice, on your next attack fire and ice will BOTH have penalties, but lightning will get a bonus. If you hit with one just one element, only it gets penalized, while the other two both get bonuses. If you hit with all three, all three will be penalized on your next attack.
The penalties and bonuses last for 5 seconds, or until they are overwritten with a new elemental equilibrium strike (ref). When soloing each of your hits will reset the resists/bonuses based on what you hit with.
The changed resistances will apply to all damage dealt to the target, whether it comes from you or your allies. However, only hits from you or your traps/mines/totems will trigger the effect - so you could for example attack with lightning damage to apply the effect while your minions or party members attack with cold and fire damage to make use of the lowered resistances.