Introduction

The Material Editor is easy to get a hang of in terms of provisioning the Diffuse, Normal, Specular, Opacity, and Emissive features of a model asset, but UDK's editor offers far more functionality than just loading up and controlling imported textures. In particular, a range of nodes access the scene itself. You can call on the scene lighting, distance of pixels from the camera, the reflection for a given surface normal, and you can even drive Materials in the scene through Scalar parameters in your code. In many of the recipes so far we have already discussed the everyday operators that you can use in the Material Editor, from Fresnel Falloff to FlipBooks. Here, we're going to focus mainly on the more difficult, but equally useful scene driven operators (and a few others that we haven't touched on so far).

From UDK versions after September 2011, a new ease of use feature has been added to the Material Editor. Material Functions are encapsulated fragments of commonly used operations...