i don't know how i should go about this. i'm making my first open world game as a hobby project, but i don't know how to do the borders. should i put a wall of rocks like watch_dogs does? but that just looks unnatural... what about an invisible wall with just an endless field like fallout 3 does? it looks natural, but i think its impractical, i know i would get pissed if i ran into a random invisible wall in the middle (or edge, in this case.) of nowhere, especially if i haven't looked at the world map in a while. i don't know how to do it the right way, any suggestions are appreciated.

i don't know how to do it the right way

There's no right or wrong way. It depends on your goal. An often used, simple, realistic border is water, therefor an island. It works for almost all settings, fanatsy,modern,urban etc.

Traditionally a combination of border types are used, for example any combination of:

• Water
• Cliffs (fall to your death)
• Mountains
• Lava
• Forcefields (better than an invisible wall)
• Impassable forest
• Fences/walls/buildings
• Instantly fatal opponents
• Game-specific arbitrary limits (e.g. collar blows your head off, game ends because you abandoned your quest, etc)
• Limited resources (e.g. theoretically unbounded but you run out of air/die of radiation poisoning/etc)
• Boringworld (can walk forever, nothing interesting will ever happen)

Islands are fine, but I personally like a combo both for variation sake and because I secretly believe I will find some way through. ;)

It would also depend on the style of game you are aiming at. I remember playing a text adventure game years ago that played to fantasy cliches and wasn't afraid to make fun of them. The edge of the world in this game was a barrier of fog with signs saying "This part of the world has not been created yet" - it worked nicely here but clearly wouldn't work in a more serious game. In these cases think what the player cannot do ... if it isn't possible to swim then islands work, if the player is flying a plane then what is the effective range before fuel runs out - these create logical barriers that don't break the player's immersion in the game.

And whatever you do don't create something interesting the other side of the 'wall' as the player will probably want to pay it a visit. Fallout 3 failed for me on this point as there simply was an invisible wall beyond which there was often something more to discover (if the radiation kept increasing until it was impossible to keep moving forwards then this would have worked and made sense to me), while I had a similar bad experience with one of the Fable games. The worst example I've seen is an impressive locked door impossible to open - I wasted hours trying to find the key, break down the door and so on before discovering (by surfing the net) that the door was just there to give the impression of a larger world.

i don't know how to do it the right way

There's no right or wrong way. It depends on your goal. An often used, simple, realistic border is water, therefor an island. It works for almost all settings, fanatsy,modern,urban etc.

Yea, I think the island setting is actually a pretty clever way of limiting the space in open world games without reminding you that there are actual borders in the game due to technical limitations. The possibility and expectation of getting lost in an endless sea is reason enough for me to stay on the island and not challenge the level boundaries.

One word: Islands.

GTA has gotten away with that for generations of consoles and PCs.

GTA 2: Islands.

GTA 3: Islands (and impossible cliff to climb at the north of 3rd island).

GTA Vice City: Islands!

GTA San Andreas: Moar Islands!

GTA 4: Isla... Well, you get the point.

EDIT: Bethesda Game Studios (creators of Fallout 3) have nice setups for Elder Scrolls in that respect.

Both Oblivion and Skyrim present challenges in the way of this since you got both land borders and sea borders in different places. They made the sea borders extend to the infinite, but for terrain borders, they actually have a heightmap of the whole continent, so thats what they show at the borders and beyond.

First off I would ask what is the location/theme you are going for with your game? Is your game primarily in some sort of wasteland or in a forest, etc. You should definitely tailor the end of the world to what setting your game takes place in. As mentioned above, the Elder Scrolls game does a good job of this by combining water and unpassable mountain ranges.

I played a game awhile back that I thought had a nice 'End of the World' feeling. The whole playable area was basically an island, except for rather than water just going off forever, a short ways out into the sea the entire water area fell off as a waterfall. It was a fantasy style game so I thought this worked well.

I definitely think you should tailor whatever you to do the type of environment/setting that your game takes place in.

Arma maps sometimes use water, but others have endless procedural wastelands beyond the edge of the map. It's pretty obvious where the line is, since ground clutter like trees and bushes cut off, and all roads end, but nothing prevents you from driving or flying forever, and fights between aircraft often range far beyond the map boundaries. I can remember a few times when I'd win a dogfight, but run out of fuel and have to ditch my plane 20km or more outside the map, which made for some awkward conversations with the rescue chopper crew. "Where exactly are you down again?"

Basically, the terrain is endless, but incredibly boring, so people stick within the gamespace.

That endless, procedural terrain is a very interesting idea.

Challenges are an opportunity for creative solutions sometimes. Seems like you could be creative with it. For example, there's a radiation zone or an endless dry desert. Spend too much time and you pass out and wake up in a hospital or something (just an example). You could combine that with the "boringworld" terrain idea? If your game has a story maybe use that for inspiration?

Or if your out of ideas use the Pac-man technique :)