Which method is used in sketches to show materials of construction?

Cross-hatching is a commonly used method in drawings and sketches to represent different materials of construction. When a sketch is created, specific patterns or lines are applied over the areas representing different materials. This technique helps differentiate between various materials visually, making it easier for readers to understand what material is being depicted in each section of the drawing.

For example, different materials might be represented by different styles of cross-hatching – for instance, solid lines might represent steel, while diagonal lines could denote concrete. This visual cue is critical in engineering drawings, as it assists in the quick identification of materials, which is essential for both construction and design purposes.

The other options serve different functions in technical drawings. Section lines indicate the cut area of a sectioned view, providing clarity on what part of the object is being examined. Dimension lines are used to convey measurements and sizes, while centre lines typically indicate the axes of symmetry or the center points of objects. While all of these are important components of sketches and drawings, they do not convey material types in the same way that cross-hatching does.