The Xbox 360 launched in November 2005 with a handful of titles, but it wasn’t until The Elder Scrolls IV: Oblivion released in the following March that gamers truly understood the power of next-generation consoles. The vast and impressively detailed open world of Oblivion won over critics and gamers alike with cutting edge graphics, high dynamic range lighting, and the innovative Radiant AI technology that endowed non-player characters with decision-making abilities and daily routines. Taken in combination, these technologies created a fantasy setting that felt more alive and vibrant than any role-playing predecessor.

In the five years since Bethesda last visited Tamriel, the studio honed its chops with the post-apocalyptic hit Fallout 3. Many of Fallout's technological refinements carry over to The Elder Scrolls V: Skyrim, but Bethesda Studios has also developed and contracted a suite of technological tools that allow the team to reach far beyond anything they've done before.

Creation Engine

Though Skyrim's Nordic setting is a more rugged environment than the Renaissance festival feel of Oblivion's Cyrodiil, the new setting isn't lacking in breathtaking views. To create a diverse country filled with steep mountain passes and dense forests, babbling brooks and violent waterfalls, glacier coastlines and snowy tundras, Bethesda went back to the drawing board and rewrote every major system powering the gameplay experience. The result is the newly dubbed Creation Engine and Kit.

“The big things for us were to draw a lot of stuff in the distance so we have a really sophisticated level of detail, more so than what we've had in the past for how things stream in and how detail gets added to them as they get closer to the camera,” explains Bethesda Studios creative director Todd Howard.

Draw distances are great for creating those postcard-worthy landscapes, but the players eyes aren't always fixed on the horizon. To give the immediate surrounding a more believable look and feel, Bethesda increased the emphasis on the play between light and shadow on the entire world.“Because our worlds are so big all of the lighting has to be dynamic,” Howard says. “That's something we had a little bit of in the past with shadowing, but not on everything. Now we have it on everything. It just makes the whole thing a lot more believable when you're there.”

A lot of the environments are dominated by the untamed wilderness, which look great thanks to Bethesda's overhauled foliage system. In previous games the team licensed the SpeedTree middleware to render the forests. For Skyrim, they've created their own platform that allows artists to build whatever kind of trees they want and to dictate how they animate. Artists can alter the weight of the branches to adjust how much they move in the wind, which is an effective way of, for instance, actualizing the danger of traversing steep mountain passes with howling winds violently shaking branches. 

Given its northern location and extreme elevations, Skyrim's climate is more prone to snowfall than Cyrodiil. To create realistic precipitation effects, Bethesda originally tried to use shaders and adjust their opacity and rim lighting, but once the artists built the models and populated the world the snow appeared to fall too evenly. To work around this problem, they built a new precipitation system that allows artists to define how much snow will hit particular objects. The program scans the geography, then calculates where the snow should fall to make sure it accumulates properly on the trees, rocks, and bushes.

Bethesda has another ten months before Skyrim releases, but thanks to the Creation Engine the world already looks much more stunning than its predecessors. The non-player characters also seem to be more intelligent thanks to alterations the team made to the Radiant AI technology.

Radiant AI

The Radiant AI technology introduced in Oblivion went a long way toward making the NPCs act in realistic ways. If you followed a citizen through his daily activities, you would likely witness him or her eating breakfast, setting out to work the land, stopping by the pub for a pint after work, and then returning home to hit the sack.

In reality, the technology driving NPC behavior wasn't overly sophisticated. Bethesda could only assign five or six types of tasks to the townspeople, and there wasn't a lot of nuance to their actions. In Skyrim, the characters have much more defined individual personalities.

You won't find townspeople loitering aimlessly in town squares anymore. Each denizen performs tasks that make sense in their environment. To impart the towns and cities with a greater sense of life, Bethesda has populated them with mills, farms, and mines that give the NPCs believable tasks to occupy their day. In the forest village we visited during the demo, most of the citizens were hard at work chopping wood, running logs through the mill, and carrying goods through the town.

The improved Radiant AI technology is also more aware of how a citizen should react to your actions. As you perform tasks for them or terrorize them by ransacking their home, the NPCs develop feelings about you. If you're good friends with a particular NPC and barge into his house during the middle of the night, he may offer you lodging rather than demand you leave the premises. “Your friend would let you eat the apple in his house,” Howard says. If you swing your weapon near an NPC, knock items off their dinner table, or try to steal something of value, they'll react with an appropriate level of hostility given their prior relationship to you.