Compendium of Design

A Body of Knowledge
Learn from those who designed before you.


There are occasions when a drawing cannot provide adequate information to indicate the form of an object or environment. In these circumstances an additional view must be drawn in combination with, or instead of, the normal outside views. The new view is called a sectional view.

Sectional views represent a view that has been sliced along a cutting plane to reveal a product or environment's inner detail.


AS-1100: Sectioning



Whenever a sectional view is drawn, the remaining solid or material components are indicated by hatch lines. Drawn at 45°, hatch lines should be drawn as thin lines and evenly spaced over the entire part.

AS-1100: Hatch lines drawn at 45&deg

Spacing of Hatch Lines

Hatching lines should be evenly spaced and as best fits across the object or component of the part or environment being sectioned. If the hatching coincides with one or more sides of the part then an alternative angle can be used.

AS-1100: Hatching
Hatching a part with 45° geometry.
AS-1100: Hatching
Hatching two adjacent parts.
AS-1100: Hatching
Hatching three adjacent parts.

Types of Sectional Views

Thin Sections

Thin sections are used to show the thickness of thin parts without having to draw the material thickness out of scale. To ensure that thickness of each part is communicated clear a minimum gap of 1mm between parts is shown.

AS-1100: Sectioning - Thin sections
Thin section.

Half Sections

Any part or environment that is symmetrical can be drawn half sectioned.

AS-1100: Sectioning - Thin sections
Half section.

Local Sections

Local sections can used to avoid showing a separate sectional view. The local area being sectioned is indicated by a continuous thin irregular line.

AS-1100: Sectioning -  Local sections
Local section

Successive Sections

Successive sections can be drawn as removed sections when, through lack of space, the sectional views cannot be shown in normal projection.

AS-1100: Sectioning -  Successive sections
Successive section

Revolved Sections

Revolved sections are used to the cross section of an arm, rib, spoke, or bar. Revolved sections are shown by drawing the cross sectional view of the part in position with the adjacent detail drawn around the revolved view.

AS-1100: Sectioning -  Revolved sections
Revolved section

Removed Sections

Removed sections are similar to revolved sections but they are drawn outside of the original part. They can be drawn adjacent to the original part or completely away from it. If drawn completely away from the part, both the section and the cutting plane must be clearly indicated to avoid confusion.

AS-1100: Sectioning -  Removed sections
Removed section

Exceptions to Sectioning

As with most rules there are exceptions. When a section plane cuts parts such as bolts, ribs, nuts, rivets, shafts, spokes, or wheels then these parts are not sectioned but shown in an external view.