The behind-the-scenes science that made The Smurfs even smurfier

July 29, 2011

This is an advertorial for The Smurfs, which will hit theaters on July 29th, 2011.

The Smurfs, starring Hank Azaria, Jayma Mays and Neil Patrick Harris, will hit theaters on Friday, July 29th. This live action/animation hybrid posed a number of challenges for the actors, like working with little dots telling them where each smurf was at any given time and off stage voice actors.

That, however, pales in comparision to the challenges faced by the animators. We got to speak to digital effects supervisor Dan Kramer about the tech of The Smurfs and what goes into giving the little blue guys life.

Kramer explained that a lot of work is done in the development stage, "We do is we put bones, we basically build a skeleton that works anatomically how we want the smurf to move, which is basically a biped, so he's pretty much like a human, although his proportions are quite a bit different. So we build a skeleton for his performance, for his proportions, and we add color rig and we add rig control, so it's basically kind of like you'd pose a little armature puppet or you might think of how someone poses something in stop-motion animation. We sort of have a virtual version of that. We create this armature basically, virtually, these little bones that then we have control over, they can grab the hand, move it around and so on. Along with that, there's a whole basic, there's a whole process of weighting the skin. Basically getting the skin to move along with those bones. And how that works. So you can do something naïve where the skin just follows the bones. You can also do something where as the arm basically closes you can increase the bicep size and things like that, so we blend in all those muscle shapes. Feels much more physical. In addition, to try to get some of the skin to feel like it's moving over the muscles. So we do everything we can to make it feel like a living, breathing creature. And not something that's just sort of a plastic toy."

One of the cooler elements to the animation of a smurf was the decision about the color of their blood. We saw a presentation a while back where they showed us the difference in the look of the creatures, depending on what color was running through their veins. Kramer told us how it all worked. "At first we tried blue blood, and it really didn't make them look small. It just made their skin look more saturated. It didn't give you that sense that you were seeing deep into the layer of their skin. And we tried green, we tried yellow, we tried different colors. And it turned out that just red blood seemed to look the best. And I don't know if that's because that's what we're used to seeing and that just made the most sense. But it basically took their skin, which is sort of a cyanish color, which, depending on the light will sort of go a little bit purple. And that's what sort of nice about it as well is based on light, based on lighting direction and how intense the light is, the hue of their skin can shift a little bit based on how much of that blood you're seeing, how much of that sub-surface color is coming through their skin. And that's a function on, again, how much light is mixing through the skin."

Lighting was incredibly important in bringing these characters to life and Kramer explained the new technology that went into it. "We had a new way of lighting our characters with a high dynamic range camera, an HDRI camera, called a spheron, which would take a 360 degree panorama view of the set. And we would do that in a new way. So basically this camera would go through and it would rotate in 360s and take just one long, large panorama picture of the set. Then we would adjust that camera. We would basically take it from a second vantage point. We would move the tripod up a specified amount and repeat the scan. The two images were so accurate that we were able to take, by knowing the distance between where the two cameras were captured from, and the two resulting images, we could take a feature that we saw from one vantage point in one image and the same feature in the other image and triangulate and come up with a distance from camera. So with this sort of stereo picture of images we were able to figure out depth for the entire scene. And we would use that to build the environments that the smurfs lived in. So we didn't just build the smurfs. We would have to build the table and the room that they lived in and texture all that stuff so that--because there's all sorts of bounce lighting that happens, and light that's imparted. Say they're standing on a white couch, you're going to get lots of light bounce off of that and you want the shadows to fall correctly on the couch. So you have to build all of that scene geometry. And that was something we had to do anyway for lighting, and as a result we were able to give all that data to the 3-D conversion houses that were working on the scenes that we weren't working on. And they were able to use that rather than starting from scratch and figuring out what the depth of the scene was. They could take our geometry and our cameras and they had a very good starting point to speed their process along."

One of the biggest challenges to animate was Smurfette's hair. Kramer said, "It was really challenging. There was a couple of reasons for it. One was her hair style doesn't really work in the physical, in a physical way. It's got a lot of volume to it. Actually, if you look at the cartoon...she sort of has a part on both sides of her head. They sort of always choreographed the part to whatever side she was looking to, so you never really got the sense of you know, something that you could really build in 3-D space. So it went through a design phase. We started to do something that would look good on a character and still sort of harken back to what her cartoon likeness would be. And there was an awful lot of volume there. And really just after a while, we actually started doing shots that way. We probably finalled about 50 shots that way. And it was a constant struggle for Raja (Gosnell), the director, to get her to look cute and appealing. And one of the things I think was just the hair, and we basically got to a point where he wanted to redesign it. And it actually helped us out quite a bit because we were struggling with the dynamics of the hair. You know, I always said that she has this big, kind of like Dallas beauty pageant, what I think of, this big beauty pageant hair. And they wanted it to move naturally, yet when you look at hair that has that much volume, you know, in real life, it's got to have a lot of hair spray in it, it's got to be really done up so it really doesn't move. Like hair would move. So there was always a struggle from the director's point of view, from the filmmaker's, and from Jordan (Kerner), the producer, to make it look like physical hair, yet we had to maintain this physical shape. This iconic shape. And it was just a battle. And eventually you know, for aesthetic reasons of just the way that she looked, he wanted to go with a little bit more of a draped, a more natural look to her hair, where it hung a bit more naturally. And that helped us out tremendously with our simulations, because then we were actually able to use gravity and not--we had all of these dynamic constraints on her hair to try and keep it in the right shape, and to get it to move fluidly, and it just really wasn't working. So it was a fortunate thing that we were able to redesign it a little bit."

The Smurfs opens in theaters on July 29th, 2011.