Tuesday, July 30, 2013

VFX of The Last of Us: Bills Town

Subtlety
This is a difficult thing to convey when working with visual effects. You want to create some movement and visible interest but it also needs to feel appropriate given the context of the environment. In The Last of Us this was particularly difficult because the weather wasn't always in some extreme state. For the most part things needed to feel calm and peaceful while being juxtaposed with horrific realities happening around you. I think it's because of this setting and tone that fools you into thinking you're safe but you know better. This brings me to Lincoln or as we referred to it, Bills Town.
Life Goes On
In Bill's Town there's only Bill, and of course the infected wandering around. No electricity, no human life. This was a constant theme throughout the game and it required us to explore other ways to create movement and life. We did this though things that weren't as obvious as animals and things of that nature. We used small swarms of flies and gnats that you end up walking through, grasshoppers that jump back and forth and loose pieces of paper trash that fly around in the wind to name a few. I personally had to really think about how to create the movement without it being intrusive or out of place. I borrowed a technique from one of our lead effects artist Eben Cook where I would take a still from the level with no effects in it yet and do some paint overs to try to imagine what effects would look good in areas. This helped a ton to see what worked and what didn't. I wanted to describe this because I think it's important to explain that visual effects in a game are not something that just get plopped down without any forethought. There are some effects that you have on hand and you know they will work well in many areas but before we lay them down we put a deal of thought into how it all fits together. This game was a great practice in restraint as well. An effects artist we could put any number of things into a scene to convey movement and so forth but you also need to be able to look at something and say "It only needs this one thing." and be alright with that. Just because we can doesn't mean we should.

Wind Effects
We have a wind system in the game that controls how things like trees and other geo behave to simulate the appearance of wind. In previous games we have created effects that best match what this looks like to us, but we were always just eyeballing it. We had to orient our emitters in the direction of what we perceived the wind to be and while this was fine it could be a little slow at times and they didn't always remain consistent. In this game we decided to ask for the ability to fetch the wind direction and strength from our global wind system so that we could use those values to control some of the behavior in our effects. I created a simple script that grabbed the wind direction and intensity and passed it to one of our global wind fields we exported from Maya. This allowed us to put things like leaves falling from trees and any other particles we wanted to have flowing in the wind wherever we wanted without having to worry about emitter orientation. So in Bills town I created a number of effects to take advantage of this, like grass and dusty dirt that gets kicked up randomly.

I created the video below to demonstrate some of these concepts at play. Ranging from subtle wind effects to in you face decapitation effects for the infected. There are spoilers so be warned if you haven't played the game yet.

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