In this tutorial you will learn how to build a geometry based on a picture. Every pixel of it gives an information that might be translated into the height of a corresponding point. All of the heights then make a surface which character may be set and parametrically changed by a mathematical rule. This surface might be connected with another piece of geometry making a facade that can be easily prepared for further stylization or manufacturing, e.g. for a vacuum press.
A heightfiled or heightmap is a black and white picture that interprets as a height array. It can be used to make a geometry-based 3D model or to tell a render engine the position and strength of texture shadows. Although there are special kinds of images for those purposes, basically, any grayscale picture can be used.
Pixel colors represent gradients from minimum height (black) to maximum (white).