OpenGL ES is a graphics library that iOS uses to do 3D rendering.
# Example Project
An example project (Git repo) (opens new window) that can be used as a starting point for doing some 3D rendering. The code for setting up OpenGL and the shaders is quite long and tedious so it wont fit well under this example format. Later pieces of it can be shown in separate examples detailing what exactly is going on with each piece of code, but for now here is the Xcode project.