What is shown on a sectional drawing?

A sectional drawing is designed to provide a cutaway view of a building or structure, which allows viewers to see the internal components and layout that would otherwise be hidden from sight. This type of drawing is instrumental in illustrating the relationships between different levels, spaces, and features of a building, such as walls, floors, ceilings, and structural elements. By slicing through the building, a sectional drawing reveals critical information about vertical dimensions, materials used, and spatial arrangement, facilitating a better understanding of the overall design.

In contrast, the other options do not accurately describe a sectional drawing. A 3D view of a floor plan represents an isometric or perspective view, which is more about visual depth rather than internal details. A blueprint of an electrical layout usually focuses on the electrical systems and wiring, which is different from the structural focus of a sectional drawing. Similarly, a detailed elevation of walls represents a flat view of the exterior or interior surface of walls, without revealing internal design or material distinctions that a sectional drawing provides.