Orthographic Projection

Sectional Views

Section Views When a part has a lot of interior details, hidden

lines can make the part hard to understand and dimension. To see the interior of these parts, we cut some of the part away. This allows for details to be seen clearly, as well as, giving us alternative locations to properly dimension the part.

Sectional Views Types of Sectional Views

Half Full Offset Removed Revolved Broken-out Aligned

Half SectionNotice how the cutting plane line runs

through the center of the part and there is no arrow head.

In a half section, one quarter of the part is cut away. This is done with symmetrical parts where you would like to show the outside, as well as, the inside details.

Full Section A full section is a view that shows what

the object looks like if it were cut in half.

A cutting plane line is used to indicate how the frontview was cut. It is also labeled in case another section

is necessary. The arrows should point in the line of sight as you are looking straight on at the section.

Section lines called Hatch lines are used to show where the part is solid. This helps to see the detail that would be

normally blocked and only shown as hidden lines.

Offset Section

Interior features not in line with each other can be shown in an offset section view.Note how the cutting plane line changes and follows the center of each feature.

Revolved Sections Used when an object has a constant shape

throughout the length that cannot be illustrated in an external view.

The section is revolved 90 degrees. It may be represented one of two ways, either broken away or not.

Not Broken Away Revolved Section

Section is revolved 90 degrees

Broken Away Revolved SectionSection is revolved

90 degrees and brokenaway from part

Broken-out Section Views A small portion of an object may be

broken away to clarify an interior surface or feature. No cutting plane line is used.

Broken-out Section View

Section exposesthe interior surfaces

Removed Sections

A cutting plane is placed through the part where the section is taken. The removed sections are not aligned with the view. Placement is in the surrounding area.

Removed SectionsSections are not aligned

with the view.

Aligned Section Views A true projection of a part with inclined ribs,

spokes, and arms will be foreshortened. An aligned section view is recommended to acquire accurate dimensions of the part. The cutting plane is bent at an angle as it passes through the object. The section view is then projected 90 degrees from the cutting plane and is in alignment to the original view.

Aligned Section Views

Cutting plane is bent at an angle

View is projected 90 degrees from the cutting

plane and is in alignment to the original view.