43 minutes ago, Wysardry said:

If you allowed characters to continue playing out of sync you could end up with any number of paradoxes.

I guess it depends how much change players can affect upon the world.
e.g. if one party is 8 hours in the future and kills a particular boss, but then a different party who are 8 hours in the past kill the same boss, then yeah, that's chronological nonsense.

If it's not a big deal to the story, you could just allow it. e.g. in Diablo, the same characters can complete the same parts of the story many times repeatedly and I've never heard anyone complain about the fact that the timeline is nonsense  

If it is a big deal, then you could apply some "fate" / "destiny" rules to protect the timeline. If you know that the boss will be killed 8 hours from now, then you have to make him immortal until that time Adjust the chance-to-hit so that the "in the past" players can't ever land a killing blow, make the boss escape into a trap-door, deliver a new quest that distracts these players ("you can either catch me or save the villiage!"), etc... A magician character could use a fortune telling spell to read "fate" and find out whether the boss has a fixed destiny at the moment or not.

You could also put a cap on how far out of sync each group of players can get. e.g. you can sleep and become up to 12 hours out of sync, but then if you try to sleep again it will tell you that you have to regroup with the other players first. You could let people send a message to the other players (e.g. "let's meet at the tavern"), which synchronizes everyone back to the same moment in time.

Time doesn't have to obey the laws of physics in a simulation, but it is going to seem very strange too the players if travel times and camping times just don't actually exist, or only last 20 seconds or so.  That's the real option if you want this "camping" and "traveling on the strategic map" to work in a real-time game, a 20 second or so delay (with a scene of a campfire or Indian Jones map travel scene or something) just to attempt to create the illusion of time passing as you do that activity when in reality you are still in real time.

What you are wanting to do would work a lot better if you were willing to make the game more of a blending of turn-based and real-time game.  At the strategic level (or "layer") it would be turn-based and you could have things like camping and map travel.  At the tactical layer it would be the a real-time dungeon crawler.  Something like the original Wizardry, or for a much newer reference Darkest Dungeon, where there is a town at the top of a dungeon and you make expeditions into the dungeon.  Your strategic map could be many towns, each with their own dungeons beneath them.  It's turn based at the strategic level and real-time in the dungeons.

One of the reasons forums for "game design" are so rarely used is that it is impossible to see someone else's vision.  I can't have any idea what you are really thinking, so maybe these examples will help.

Your problem is that you want to cheat time in actual, real-time... which even my Rube can't do.  If you create "artificial time" and run a simulation on that you are not bound by the laws of physics and can do things that might appear to be "time travel" to the audience or other simulation designers.  But you want the game to run on actual real-time, with players sitting at their computers playing in real-time, and then too play with time in ways that amount to time travel.  This can be done, but not when the simulation is running on actual real-time and the players are playing in real time.

You could do something similar too what you are wanting to do by "severing" the game into two layers like I mentioned in the previous post.  If the strategic layer is turn based you can "cheat time" within the strategic layer, then when players go questing they are in your real-time open world and are bound by the laws of physics "during the day".  With the strategic layer "severed" from real-time doing what you want to do becomes easy.

You can't cheat time in actual real-time with the players watching in real-time.  Like a magician, there needs to be some type of "misdirection" going on if you want to cheat time.

"Time is the fire in which we burn..."

Since you are hitting on a subject that I have spent a lot of time thinking about over the last 30 years or so I thought I'd add a little more to try and help you with what you are trying to do.

A real-time “open world” is the “glorious vision” of many, many game and simulation designers and has been for decades. It is, ultimately, something very much like “The Matrix”. That is ultimately the “glorious vision” that everyone has about what people today call “open world games”. This is why games like No Mans Sky are so disappointing to everyone when they are released, and why I always know the instant they are announced that they are going to disappoint everyone when they are released. Everyone is envisioning “The Matrix”. I actually know how to do it, and it is a decades-long thing to actually achieve even a primitive and mostly empty version of it. That “glorious vision” can be achieved, but not as a commercial game.

All games and simulations are abstract, it is only a matter of the level of abstraction. Both Checkers and Chess are highly abstract representations of war in the “Age of Kings”. Like all games, especially commercially viable ones that won't take 80 years to make, your game will ultimately be very abstract in many, many ways. It will not be the glorious vision of “The Matrix”, it will be a game with almost no content compared to the real world. One definition of game design is choosing which aspects of reality to represent and which to leave out, or which to emphasize and which to de-emphasize... because you can't actually “represent everything”.

So, one thing that would make what you are trying to achieve much more attainable would be to not ever use or mention time. No years, months, weeks, days, and certainly not hours or minutes. You can still have night and day. Players in a game have very little “situational awareness”, as Hollywood directors say “the camera only sees what the camera sees”. With no time represented other than night and day, it becomes easy for the passage of time to be “severed” from time here in the real world.

The players would never be in sink with each other, other than whether it is night or day for them. You might have been playing the game all day camping and traveling withing the severed “strategic layer” of the game, and I just started playing 5 minutes ago... but we can still wind up in the same real-time quest area at the same time, and it will be either night or day for both of us. Of course, in reality you might have years of play time while I am a new player.

To do what you are wanting to do you need to “sever” the strategic (camping, travel, etc) layer of the game from the tactical (real-time questing) layer of the game. The “magician's illusion” of being non-specific with time other than if it is night or day would allow you to make this happen in a real-time multiplayer game... but it wouldn't be that “glorious vision” of an “open world”. It would be “Places” that were like an open world within a structured strategy layer that both allows you to “cheat time” and contain the game to something that can actually be produced within a reasonable amount of time.

As long as you are envisioning a "fully real time world" then there isn't any way to "cheat time" in the way you are wanting to do.  As long as game time is matching real time at all times wherever you go, and there there is more than one human player in the same game location, there isn't any way to "cheat time" that isn't going to be very noticeable.

Almost all games have a strategic layer too them, in an RPG it is the towns, travel on the "world map, camping, etc.  Just about everything that doesn't involve questing in real time.  You are wanting to incorporate the strategic aspects into the tactical layer, which is what "open world" games do.  That's "reality".  That is, ultimately, "The Matrix".  So the question you want to ask yourself is if you want to make a really bad and empty version of the "glorious vision" of The Matrix or the best and most engrossing game that you can make.

You should play Darkest Dungeon.  It is about the exact opposite of what you are wanting too make, and it is probably the best computer game made in the last decade.  A real-time world you can "live" within is a dream of a lot of people, but it is by far the most challenging "game" that you could possibly attempt to make.  On every level.  Technologically, production time, and making a good game out of it.  On every level it is the hardest thing you could possibly try to do.  And anything less than a decade long project is just going to result in a boring, empty place.

You have to "contain the design" somewhere, it can't just be "like real life on an entire planet".  Where you pick and choose to do that is one definition of game design, but the way you are wanting to have players be out of sinc in a real-time multiplayer game, one obvious way for you to do that is to have a turn-based strategic layer and real-time tactical layer.  With time being only night or day, players in the same location on the world map play either night or day missions (which would be very different types of missions) and will play with other players in the same location who choose the same time of day mission.

If every town on your map was a Wizardy/Darkest Dungeon-like place (a town with a dungeon beneath it)... I know I'd love that game!  And its something you could realistically do, as opposed to "real-time on an entire planet" which, if you manage to do, would inevitably be empty and boring like everyone else's attempts to do the same thing.  You have to "contain the design" somewhere... unless you are working for the military, haha!