We discovered early in the first chapter that man-made materials will often closely resemble their natural surface attributes. Slate is a natural material that is used in many building projects. Its tendency to shear into natural slices makes it an ideal candidate for roofing. However, in its man-made form it is much more regularly shaped and graded to give a nice repeating pattern on a roof surface. That doesn't mean that there is no irregularity in either the edges or surface of manufactured slate tiles. In fact, architects often use this irregularity to add character and drama to a roof.
Repeat patterns in a 3D suite like Blender can be extremely difficult to control. If repeats become too obvious, particularly when surface and edges are supposed to be random, it can ruin the illusion. Fortunately, we will be employing Blender controls to add randomness to a repeated image representing the tiled pattern of the roof...