From Morrowind to Skyrim: how Bethesda built its latest gameworld

Skyrim! Jewel of the north, farthest frontier of Tamriel. Land of sparkling peaks and gloomy caverns! Land of frost, and giants, and frost giants!

Skyrim! Where wolf packs roam primeval forests in search of juicy, nourishing peasants. Where men in horned helmets smash seven shades of sherbet out of each other with hunks of repurposed masonry. Skyrim! Open to all, regardless of age, race, profession or pillaging propensity, providing you can stomach the risk of being sat on by a dragon.

Assembling a realm as vast and lore-saturated as this would surely take legions of Nordic deities centuries, nay, millennia of effort. Actually, the next Elder Scrolls game has been in development for a little under five years, with a level design team of eight. But that's a long time for a videogame, and a hefty step up in manpower since Bethesda's last trip through Tamriel, Oblivion.

Hand-made

For Todd Howard, game director and executive producer, Skyrim represents the studio's greatest labour yet - and when a developer's credits include the likes of Oblivion or the comparably gargantuan Fallout 3, it's safe to assume they have a pretty high tolerance threshold for toil.

Skyrim boasts fewer major cities than Oblivion - five as against nine - but there's zero auto-generation of environmental assets. "We did a mix in Oblivion," Howard explains, "but with Fallout 3 and now Skyrim, the world itself is all hand crafted.

"We place every tree, rock, cup and such. But we still have random elements like creatures, quests and encounters."

As in previous games, the sheer size of the playable area coupled with the need to let players tackle it any which way poses immense technical challenges. Some developers boost performance or texture quality by carefully limiting the view, dialling down detail on the periphery of the action. Not so Bethesda.

"When it comes to rendering, in most games you're trying to hide geometry and cull things out for speed, often blocking the player's view," comments Howard.

"We sort of enter it by knowing that we have to draw it all, that we're going to be having a view distance that is 'all the way', and we don't want to limit the player.

"So our focus becomes one of level-of-detail streaming. You can stare at a fork, or an apple, and then look up and see a mountain, and you can then run to the top of that mountain.

"Dealing with those extreme changes in resolution are what cause us the most headaches - we want all the micro and macro details.

There's a similar balancing act at stake when it comes to the beefed-up Radiant AI, which gives NPC townsfolk a degree of independent-mindedness, and the all-new Radiant Storytelling system, which tracks your every itty-bitty decision and alters the play of options appropriately, including where and by whom you're offered quests.

Carelessly drop an axe in a forest during an afternoon's bear-slaying, for instance, and a merchant chum might retrieve it for you later. Behead him as punishment for running his filthy, lucre-loving fingers all over your prized weapon, and he won't be able to enlist you as a caravan escort - but his unsuspecting widow might. You get the idea.

"When it comes to the world being dynamic, we have to spend a lot of time on 'what if' scenarios because our players can do what they want, often in the order they want," Howard goes on.

"You can be on 20 quests at once, we don't shut any of them down when doing one, so we seem to be constantly adding new elements to our quests depending on what the player has or hasn't done."