Full section View
A full section view is one in which the cutting plane passes entirely across the object, so that the resulting view is completely in section.
The cutting plane may pass straight through, or be offset, changing direction forward or backward, to pass through features it would otherwise have missed. Sometimes two views are drawn in section on a pair of cutting planes. In such cases each view is considered separately, without reference to what has been removed for another view. Thus shows the portion remaining and the cut surface for one sectional view, and for the other sectional view.
Half Section Views
This is a view sometimes used for symmetrical objects in which one half is drawn in section and the other half as a regular exterior view. The cutting plane is imagined to extend halfway across. A half section has the advantage of showing both the interior and exterior of the object on one view without using dashed lines. However, a half section thus made is difficult to dimension without ambiguity, and so if needed for clarity, dashed lines may be added.
Note particularly that a center line separates the exterior and interior portions on the sectional view. This is for the same reason that the change in plane direction for the offset of the cutting plane is not shown and no edge exist on the object at the center.
Broken Out section
Often an interior portion must be shown but a full or half section cannot be used because the cutting plane would remove some feature that must be included. For this condition the cutting plane is extended only so far as needed, and then is though of as “broken out”
Removed Sections Views
These are used for the same purpose as rotated sections, but instead of being drawn on the view, they are removed to some adjacent place on the design. The cutting plane with reference letters should always be indicated unless the place from which the section has been taken is obvious. Removed sections are used whenever restricted space for the section or the dimensioning of it prevents the use of an ordinary rotated section. When the shape of a piece changes gradually or is not uniform, several sections may be required. Sometimes section are removed to a separate drawing sheet. When this is done, the section must be carefully shown on the main drawing with cutting plane and identifying letters. Often these identifying letters are made as a fraction in a circle, with the numerator a letter identifying the section and the denominator a number identifying the sheet. The sectional view is then marked with the same letters and numbers. The ASA recommends that, whenever possible, a removed section be drawn in its natural projected position.