The shaping, deformation and animation of the Hulk are the focus and difficulty of special effects work. The scene where the Hulk appears in the film lasts about 20 minutes. Ang Lee hopes that the green of the Hulk will change in the movie, starting with a little green, and then gradually increasing the green to blue-green and finally a bright green. In order to achieve different responses to various greens under different lights, special effects artists use a small green silicone model as a reference when shooting the movie, so that the rendering of the CG model is exactly the same as the actual shooting scene.
It is difficult to establish the depth of the skin. The most important thing is the binding of the epidermis and bones, including the binding of facial expressions. Some simple character animations are made using Maya, a commercial software that won an Oscar for technology award in 2003, and most complex animation scenes are completed using Cari, a software developed by Industrial Light & Magic, which is only for internal use. Flesh Light, another internal software, played an important role in the interaction of the Hulk's bone-muscle-skin. After the skin is stretched, it is different from the loose skin. Flesh Light is designed for this complex muscle movement. It allows the animator to control the elasticity of the skin from any node like a flexible net.
