The year: 1191 AD. The Third Crusade is ravaging the Holy Land. You are a master assassin named Altair, cunning and ruthless. Your mission: to take out principals on both sides who are propagating the hostilities. But be careful. Your actions can throw your immediate environment into chaos and change the coarse of history.

Assassin's Creed, Ubisoft's first next-gen videogame, has taken four years and a corps of some 300 artists and technicians to complete. All images © 2007 Ubisoft Ent.

It lasted nearly as long as the Crusade it replicates and involved a small army of professionals. Assassin's Creed, the ambitious first next-gen videogame created by Montreal-based Ubisoft (Prince of Persia, Tom Clancy's Splinter Cell), has taken four years and a corps of some 300 artists and technicians to complete.

Produced by Patrice Desilets (who also serves as creative director) and Jade Raymond, this highly anticipated game recreates the 12th century Holy Land with the Third Crusade raging through the cities of Jerusalem, Damascus and Acre. Open-ended and teeming with interactive citizenry, the historically accurate locales serve as the theater of operation for the treacherous and skillful Altair. "Assassin's Creed attempts an ambitious blend of organic design, freedom of gameplay, crowd behavior and social realism within an authentic historical environment," Desilets observes.

"Assassin's Creed is totally interactive," states Technical Director Claude Langlais. "Rather than specifying what actions Altair will take, the player hits buttons corresponding to his various body parts and the game attempts to figure out what action should be taken. Also, the game's 'social stealth' -- the ability to blend in with a crowd by performing actions that would be socially inconspicuous -- is a huge selling point."

The Assassin's Creed team also included Vincent Pondriand (associate producer), Mathieu Mazerolle (lead engineer), Alexandre Drouin (lead animation) and Raphael Lacoste (artistic director).

The design decision to make everything interactive required Ubisoft to build a new engine and completely redefine the way they work. On most games, modelers and level artists spend most of their time thinking about making great looking levels, but on Assassin's Creed artists also have to learn level design rules. Since there are huge open cities it is not possible for any one person to own the creation of a whole map. Artists instead have to work cooperatively to build the city, some focusing on houses, others on landmarks and others on objects. Furthermore, it's not enough just to make sure that your house looks good and fits within budgets. On Assassin's Creed, artists have to start by making sure that their design works with the character and level design rules and only after that can they think about making it look good.

Developers started by evolving the system that they used on Sands of Time to assist Altair's climbing and jumping across buildings. Their main goal was to generate interaction points automatically, so that the tedious task of flagging interactive edges could be done by the tools instead of level designers. It required a fair amount of testing from their level designers to mature the system, but it was functional and ready for production relatively quickly. The time the Ubisoft team spent developing and testing the tools has more then paid for itself. There is no way they could have manually flagged every ledge in each of their three huge cities to be interactive.

The crowd was another important gameplay ingredient. The developers wanted a more action-packed type of stealth, one that was much faster than traditional stealth and that really took advantage of all of the work they put into crowd simulation. Instead of using the hidden in shadow rule, they used the rules of everyday life: you are hidden when you are behaving in a socially accepted way. Think about walking around in a crowded city such as New York or at a crowded concert. In crowded circumstances, it is very easy to go unseen by simply obeying rules that everyone knows: follow the crowd flow, walk at the right pace, don't aggressively shove people out of the way to make room for yourself, don't start yelling at the top of your lungs, etc. So, they put these real life social rules into the game, which makes for an intuitive environment and also a lot of fun when a player decides to break the rules by shoving people around and causing a commotion that go against the norm of everyday life.

This means that each civilian is a gameplay component that can either help or hinder the player's progress. In order to create a crowd that the player can use as a strategic advantage, the Ubisoft team had to build a layered system. There are four levels in all. The lowest level handles the individual needs of the population and creates believable street life when the player does nothing. The highest overarching layer manages the crowd's global Alert State, dictating the amount of crowd panic and triggering specific military tactics. In between there is a whole lot of code to handle crowd allegiance so that the townspeople's attitude toward you evolves based on the actions you have taken. It is quite complicated when you dissect the system in technical terms, but to a player the system will seem very intuitive because the rules are based on everyday life. If you do things that are socially acceptable you are anonymous and therefore hidden. If, however, you start behaving in an abnormal way, climbing walls in broad daylight or pushing people around, you are likely to attract the attention of the crowd and they may then alert the guards or your target.