Stack a smooth velvet cushion, a chunky knit throw and a soft chenille rug in the same shade of gray, and the room reads far more dimensional than the color alone would suggest — the difference is how each surface catches light and would feel to the touch. It's depth built from material contrast rather than color contrast.
A common rule of thumb: give the largest surfaces (a rug, a sofa cover) a texture with visible weave, mid-sized pieces (a throw, cushions) a different knit or velvet, and small objects (baskets, vases) a natural material like rattan or ceramic — aiming for at least three distinct textures in one space.
An all-smooth room reads flat; an all-rough one reads heavy. Alternating smooth and rough textures makes the difference visible even without touching anything.
When to use
Use it when a monochrome room feels flat. Assign a different texture to the large surface, the mid-sized pieces and the small objects — aim for at least three.