Development director Tommy Francois revealed that its method of performance capture, which tracks actors' motion, facial movements and voice over all at once, is a "first in video games".
"What we're hoping to get from that is to deliver cutscenes where we can really get emotional, where we can get much closer to characters to convey more emotions," he said at a press briefing attended by Digital Spy.
"We have better cloth, as well, as for making our engine better. But one of the physical improvements is also on non playable characters, they have more interactions with the main character, they also interact with one another."
Ubisoft has said Assassin's Creed 3 sets several development standards for the franchise, such as having the longest development time since the original in 2007, as well as the longest Alpha period, which is the first time the game is playable from start to finish.
"The sooner we finish this, the more time we have for polish," said Francois. "So [for] the first time for the Assassin's series, apart from having absolutely phenomenal production capacity, we make sure that we have this in Alpha for six months prior to release.
"This gives us six months to tweak, polish, make things look better, change what needs to be changed when it makes no sense."
Headed up by Ubisoft Montreal, the title is being worked on by staff from the first two Assassin's Creed games and Prince of Persia: Sands of Time, and will be assisted by a further eight studios across the globe.
It will also offer a new graphical engine named Anvil Next, which powers new visuals and weather effects and variable seasons.
Assassin's Creed 3 will be released for Xbox 360, PC, PlayStation 3 and Wii U on October 31 worldwide.
> Read our first-look preview of Assassin's Creed 3
View the teaser trailer for Assassin's Creed 3 below: