The biggest VFX were the witch face up in the sky, which was a full CG volumetric simulation, as well as the bravura Angry Aggie pyrotechnics at the end (also nominated by the VES), which was a combination of a real puppet and enhancement of hair, dress, energy, and the yoke of spectral stuff around her that was all done in post.
"Aggie's a perfect example of a practical puppet, but we also used a lot of 2D animation and CG animation in order to bring her to life," Butler adds. "Having our own in-house VFX department being part of that process every day meant that at no point was VFX just post: it's not an afterthought to make something look prettier. It's an integral part of every scene. I always wanted Aggie to be this young girl at the center of all this fury.
"The best thing about getting our look was that Nelson Lowry, our production designer, went off on such amazing tangents: we had people blowing ink to create the Tesla Coil effect on her head; we had a visual development artist building Aggie out of glue and blown glass, paper, and wire. We were having textures animate through the printed faces, which were then blasting with light, so we got all these crazy effects."
For the tornado, smoke, electrical storm and ectoplasm-like wisps on the ghosts, they used Tulle, a thin bridal veil material. But they made an emaciated puppet and all the things that would be too difficult or too time consuming on stage were done as VFX. "Once the puppet animation was done, we tracked her body and then attached a CG dress to it so it was flowing and constantly moving (using Nuke, Maya, RenderMan, and Houdini)," Van't Hul suggests. "But a real physical dress was made first and then scanned in to make our CG dress."
Inevitably, Butler says there's always the danger of ending up with too much on screen and having an overdose of eye candy when you have so many driven artists. So they had to pull back some. After all, despite all the naturalistic advances, this is still stop-motion. And nothing should get in the way of the tactile fun and unique stylization.
"Behind the Scenes of ParaNorman: Angry Aggie"