17 hours ago, Noddy92 said:

What is the best way to calculate action points or time units for one-two system?

Do you mean for a hybrid system? I thought the point of the one-two system is forgo the whole action point thing.

I suppose you could still use attributes to influence action extent (how far you can walk, maybe which abilities you can take). Personally, I don't much like to have the "AP attribute", as it becomes kind of a dump stat that you pump until you can use X and Y in the same round. Have you thought about reducing the required AP for actions based on related attribute (strong guys can swing the hammer more, bot not necessarily run more)? 

It perhaps just need to be as simple and transparent as possible (e.g. every 2 STR = -1AP or something like it) to avoid becoming overwhelming.

I was thinking of higher the skill, the fewer action points you use. For instance, the higher aim means less AP to aim specific body part, or higher medical less AP used to heal someone, etc.

I was suggesting the one-two system as an alternative to points buy, but I may have misunderstood the premise. Also, it was only a suggestion

Another suggestion would be to be very, very sure that you want players to be able to increase or change action points. This will be incredibly difficult to balance as, without a doubt, the ability to do more (specifically take another shot), gives an incredible advantage.

If it were me, I'd go with the one-two system, and instead of adding additional action points, I'd look at something easier to control or calculate, by changing the actions themselves. As an example, if a player has a particularly high agility, he or she moves a square (or two) further during a movement action, or a player with a high accuracy can take an aimed shot as though it were a normal shot (as a large action, instead of a full turn action). These things are much easier to balance ahead of time, and they avoid undermining the main benefit of using a one-two system - quick calculation and early planning.

11 hours ago, SomeoneRichards said:

Another suggestion would be to be very, very sure that you want players to be able to increase or change action points. This will be incredibly difficult to balance as, without a doubt, the ability to do more (specifically take another shot), gives an incredible advantage.

Changing AP makes sense if you can save some to use on the following round. 

One game that popped into my mind just now that you could study a bit is Underrail, which was fairly well received. It's rather modern, but uses a very classical style system. Take a look at what people said about it (also in forums to see what people are doing in such a system) and play for some good hours to see where it hits and where it falls short (it take some hours until it does). For a first prototype, I'd try to iterate over that and see how it comes out. Test it and see where it needs improvements. I believe this would be a very sensible way to go about.

I see how the player can benefit from one-two in case of planning and calculation, but I'm developing an RPG-Strategy hybrid. I came across an interesting problem in which I want to use the same type of weapon, but with same ammo (different 9 mm guns), so I'm thinking a more streamlined and easy to understand AP system.

I haven't played Underrail, but I hear it's a lot like Fallout, but I will take a look at it, thanks.

Aren't dexterity and agility similar characteristics? I wouldn't use both, that seems confusing.

There's some overlap between the terms, but dexterity has more to do with the hands specifically while agility relates more to full-body movement.

I thought so too, Agility and Dexterity, and their practical use in the game. Dexterity can be used to perform the more precise action, such as defusing a bomb, but I would combine this with the Explosives skill.

Doing even more research on this topic, I'm more in favor of AP, because I can get more depth, but I'm having trouble with the formula. I stumbled across two formulas, one for Fallout 1 which is more simple Agility = Action points, and one theory about Jagged Alliance 1 which seems to use the following Health + Agility + Dexterity + EXP Lvl. The latter formula does seem more to what I want to use, but I'm wondering if this is too much stats to just get the Action points. Please note that in JA1 the lowest AP is 8, while the highest is 25, and there is no character creation. 

I just wanted to ask how many stats should I use to get AP formula. Thanks 

Again it depends on what kind of game you want to make.

Complicated/many stats = Slower. Feels more like a simulation. The player needs to calculate more.
More streamlined = Feels more like a tactical game, like chess.

I would prefer to easily understand what each stats do, than a system that might seem more "realistic" on paper. These often do not work out so well in games. I want my choices when choosing or developing my characters to be distinct and have a ingame effect.

I understand what you are saying, and my game will definitely be a bit streamlined because I don't want to clutter the screen with unnecessary numbers and stats, so some streamlining is in order.

That being said I was wondering what was more easy to understand, for instance, Fallout 1 had only 10 AP, while Jagged Alliance had a max of 25, and Xenonauts had AP go up to 100. Did the higher numbers confuse the players, because personally while playing JA for the first time I found it a bit unusual to have 25 AP, but I quickly got the hang of it and in Xenonauts 100 AP, I  heard people calculated like 10.0 or some people do that?

Anyway streamlined definitely, but not too much, just the boring stuff, and statistics and other not so much important aspects of the game.