When sectioning multiple components in an assembly drawing, the goal is to reveal the internal structure of each part while making it clear how the components fit together. To achieve this, the cutting plane passes through the entire assembly, and each part that is intersected by the plane is shown with section lining. However, to maintain clarity, the hatch patterns are varied slightly between parts—either by changing the angle, spacing, or orientation of the lines—so that adjacent components are visually distinct.
It’s important to note that not every part in an assembly is sectioned. For example, fasteners such as bolts, nuts, washers, keys, and shafts are usually left unsectioned even if they are cut by the plane. This is a convention intended to preserve the recognizable shape of these standard components and avoid visual confusion.
In complex assemblies, partial sections or broken-out sections may be used to focus attention on specific areas without overwhelming the drawing with unnecessary detail. Careful use of section lining, consistent material indication (if hatch patterns are used for that purpose), and clean separation between components all contribute to making an assembly section view readable and effective for communication in manufacturing and design.