Which property of form is primarily concerned with the physical characteristics of an object's surface?

The property of form that is primarily concerned with the physical characteristics of an object's surface is texture. Texture refers to the tactile quality or visual appearance of a surface, describing how it feels (smooth, rough, bumpy) or how it looks (matte, glossy, patterned). This property plays a significant role in how we perceive an object; it can suggest material composition and influence the overall aesthetic experience of a space or object. Understanding texture is crucial in architecture and design, as it affects both the functionality and sensory perception of buildings and spaces.

Visual inertia relates to the perception of mass and weight, which is more concerned with the visual stability and impact of an object rather than its surface characteristics. Orientation deals with the position or alignment of an object in relation to its surroundings, which does not directly relate to the surface quality. Size pertains to the dimensions of an object, influencing its overall scale and proportion rather than the specifics of its texture. Thus, texture is the most appropriate choice in this context.