Walt Disney Animation Studios' latest 3D computer animated adventure is Wreck-It Ralph. The pic, directed by Rich Moore, follows an arcade game villain seeking a new existence in the gaming universe. We talk to visual effects supervisor Scott Kersavage about creating multiple worlds, new shaders, camera-capture and crowds.
fxg: What would be one of the greatest challenges for Disney on Wreck-It Ralph?
Kersavage: One of the biggest challenges was the different worlds, mostly because they were so different in design language. For each one we had this notion that you had to feel you went into one Cineplex and then came out and went into another one. It was something John Lassetter was very specific on - he wanted each world to feel very unique and very different.
We had three big worlds, and then smaller ones. The first big world was the Fix-It Felix, Jr. game. That was more of an 8-bit style Donkey Kong-esque game. Everything in that world had to be right angles, really mimicking the pixels of the 8-bit design of those early games. We actually mimicked not only the design of the environment but also we limited camera moves, animation style to be very reserved. Our animators are used to working in a much more fluid, more classically style Disney animation.
fxg: Did you have to almost 'degrade' your work for that world?
Kersavage: That was the interesting thing. We tried to come back all the way, even in the sense where we were trying to take the lighting and bring that back to a point where it was almost toon-shaded. We realized that Ralph and Felix - once they started to get to a certain point it didn't become as appealing when they were rendered more visually rich. That drove us to a place where we had to have certain rules about the way something moved or the overall design of the world.
fxg: Sugar Rush is another of the worlds - how was that realized?
Kersavage: That actually lent itself to a more classically styled animation - it had some of the things we would bring from our traditionally trained artists. We actually had an effects designer on the show who would draw specific effects. Ralph has a pod he crashes into a candy cane forest and so all the cake debris flying up from the surface of the ground - we had traditional animators draw that to give us an indication of what we should do in the digital world.
So in this world we had more things that were design-y and blobby in nature and had cute and appealing shapes. That's a challenge in itself because you're not going directly with a sim that's coming out as a smoke or fluid renderer or something like that. In that world, too, everything is made up of food, so from a lighting perspective we completely revised our shading system to include a new BRDF and to incorporate area lights and IBLs so that we could really get the response off the surface materials to be much more physically based. We did that because our early research showed us that humans really like to know what we eat - we're so familiar with that, so we know when something looks right or appealing.
fxg: What about Hero's Duty which has a lot of action and is much more frenetic?
Kersavage: That was a world in the style of Halo meets Aliens. What we really wanted was very frantic behavior as far as camera moves go. We would incorporate hand-held camera moves and reference Saving Private Ryan, Aliens. The animation style had to also be the most robust in the film - almost the most realistic. We did a lot of studies of athletes and we had some trips to military bases to see the moves they did. Inside of that world everything was at 45 degree angles than it was in Sugar Rush. Hero's Duty was very sharp diagonals.
We also went full on with fluid sims and lots of volume shapes and lights. We had particulates in the air as well - something we noticed in the live action films where the frenetic nature would be added to with dust and particulates in the air. When we were first done with that world, it was a little too clean and CG does tend to get that way, so we added more atmosphere in the air and that really pushed it over the top to make it more realistic.
fxg: What were the tools you were using for the crowds in Hero's Duty?
Kersavage: We had a crowds team - we knew on the show there'd be crowds for Hero's Duty which have the flying bugs, one-off shots for the bleachers in Sugar Rush, Game Central Station which is like an airport terminal. The crowds team was a subset of effects - right from animatics stage and populating the worlds with an indication of the density of the proposed crowds.
We incorporated Massive into our pipeline which was something we hadn't done previously. We did lots of research into trying to understand crowd behavior - we have the benefit of having the Walt Disney Imagineering organization very close to our studio. They do a lot of crowd research based off the theme parks and how to set up the most appropriate design for various venues. They work out what the best way to get a crowd in and out is and make it the most enjoyable experience.
fxg: Were there any other significant tech advancements on the show?
Kersavage: We incorporated camera capture into our system on Ralph. We really needed it to work with Maya - so there was an effort that started with animatics and all the way through and was also used later on in the film to do hand-held work.
Our data pipeline was also upgraded. We had developed dLight on Tangled as an interface tool for the lighting artists, helping them seeing the data, manipulating lights and getting renders happening. The data below was not as easily set up, so for Ralph we paired up the data pipeline and modified the tools so they could read the data pipeline underneath. Actually, one of the things I'm most proud of is that we didn't really have a lot of data issues on the show. We were able to handle huge amounts of complexity. Each scene seems to be filled with so much environment and character data.
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