Are there any rules about "energy" in any D&D version? [closed]

Question

I am developing a turn-based combat game that uses D&D rules (as much as possible) as its foundation. The relevant rules are around concepts such as movement, distance, range, HP, AC, to hit, and damage. The game is almost entirely focused on combat, and to balance the fact that fighters can effectively keep swinging a sword until their arms fall off, I am implementing an "energy" system to introduce some form of action economy.

The way energy works is by being depleted every time a character makes a move (1 tile generally = 1 energy point) or uses a weapon (energy points vary by weapon weight, but for example fists = 1 energy point). Also, wearing heavier armour/equipment taxes your moves/attacks more than normal.

Is there anything like this energy management system in any D&D rules? I'm open to drawing from any version (Basic, 1e, 2e etc.), supplements, magazines, potentially other games like Pathfinder, or even other computer games that have a similar system.

To address some of the questions raised:

Q: What do you mean by D&D based? A: It's a medieval fighting game that uses the same weapons and items as D&D, uses the d20+ system for determining hits, damage etc., but only has one race/class: human fighter. There are no other skills, feats, attributes etc. to worry about.

Q: When does "energy" refill? A: It increases slightly every time you "defend" (effectively don't take an action) during a turn. To give an example: assume a player starts with 10 energy. If he moves forward 4 tiles, that's 4 energy so 6 remaining. If he swings a punch, that's 1 energy so 5 remaining (if he had a sword, it would cost 2 energy). If he now "defends" he gets 2 energy back, so 7 remaining.

Q: In what way does the existing action economy not already address this problem in a satisfactory way? A: There would not be any tactical decisions to make about moving, attacking, switching weapons or defending based on how much energy you have in total/remaining. Without energy, the most effective way to fight would be to close with your opponent and keep swinging until one of you falls, and your tactical decisions would be based solely around your remaining health. Without energy, if you wanted to run away you simply would do so: with energy, you need to decide if your remaining energy would get you far enough or if you should expend it on continuing to attack, judging by how much health you have vs your opponent. You may want to switch to a lighter weapon - less damage, but less costly to wield.

Q: "Stamina" seems like a better word to fit this use. A: You're spot on - it's actually called stamina in my game concept, I just used the term energy for this question as it's a more generic term that more people would understand.

Answer 1

You might also want to take a look at the Exhaustion system of 5e. It may not be quite as granular as you're looking for, but it is the existing 5e "how long can I keep doing this physical activity" mechanic. You can find it on page 295 of the 5e PHB.

Earlier editions had their own systems for fatigue and exhaustion. In essence, while 3.5 just has a trinary state (fine-fatigued-exhausted), 5e has Exhaustion levels, with 0 being fine, mounting penalties up to exhaustion level 5, and death at exhaustion 6.).

Answer 2

I'm not aware of any system for "energy" that works as you describe in Dungeons & Dragons. The closest thing would be the systems for psionics which first entered the game in the first edition. "Psionic power points", as the name suggests, are used only for psionic powers and attacks, not for things like movement or physical attacks during combat. The various alternate "spell points" system used for Sorcerers and other spell-casters in various editions are likewise confined to spell-casting.

Pathfinder second edition's common pool of three actions per turn, while a lot simpler, is used for all actions - including movement - which have variable costs of one, two or three actions. (This is in contrast to the recent editions of D&D, which break the turn up into different kinds of action - though in fourth edition you could substitute some action types for others, making it a bit like Pathfinder 2E.)

In videogames, there is one match I can think of which is pretty close: the D&D-like videogame Table of Tales: The Crooked Crown, on PSVR and Steam. (Full disclosure: I worked on the game, though only on the narrative - I didn't design the combat system.) In Table of Tales, each character has a number of "power pips" that can be spent on their combat abilities (there's no standard attack equivalent, so they have to use these) or additional movement (they each have a speed they can move without spending pip expenditure). They can also rest at the end of their turn, regaining health equal to the number of pips they have left.