Creating a path or road material presents some really challenging issues for the material designer. We could just create an image and map it to the whole road surface. However, the image would need to be of sufficient size so that it would view correctly in either close-up or far away. Think of the yellow brick road with Dorothy, the Scarecrow, Lion, and Tinman seen at close shot dancing away along the road into the distance. Rather than have some enormous image applied to the whole road, is there some way we can create a repeating texture that appears not to repeat?
Another issue with applying an image to a path or road surface is that it will rarely be flat and straight. So, how do we make it curve and dip and rise as an interesting path might do in reality?
You may be asking why not just unwrap a curved road as a UV texture? Well, although theoretically possible, the mapping would be very distorted and would require a tremendous amount...