Texture lives at the edge

The eye reads texture at the boundary of a form and assumes it continues inside. So a foliage clump needs leaf-like marks only along its silhouette; a stone wall needs stones only along its top edge and around its openings; a thatched roof needs straw only at the eave. Inside the shape, flat tone that carries the light.

This is an economy that every master in this program uses and every beginner violates. Texture inside a mass does three bad things: it flattens the form by destroying the light-to-shadow gradient, it competes with the focal point, and it takes an hour. Texture at the edge does the opposite of all three.

The edge marks themselves should be broken, varied in size and direction, and pointing outward from the mass. A regular, even edge texture reads as a pattern, not a surface.