Sketching and Dimensioning Key Terms

Explanatory notes added to a drawing.

• Extension Line

• Annotation

• Plane

• Sketch

A line type that is used to indicate the axis of symmetry for a part or feature.

• Hidden Line

• Object Line

• Centerline

• Construction Line

Thin lines that serve as guides while sketching or drawing.

• Hidden Line

• Object Line

• Centerline

• Construction Line

The distance from front to back.

• Depth

• Width

• Height

A straight line passing from side to side through the center of a circle or sphere.

• Diameter

• Radius

• Plane

• Scale

A measurable extent, such as the three principal dimensions of an object of width, height, and depth.

• Annontation

• Dimension

• Thumbnail

• Perspective

Thin lines capped with arrowheads, which may be broken along their length to provide space for the dimension numerals.

• Dimension

• Isometric

• Dimension Line

• Object Line

A thin solid line perpendicular to a dimension line, indicating which feature is associated with the dimension.

• Object Line

• Extension Line

• Dimension Line

• Hidden Line

The measurement of someone or something from head to foot or from base to top.

• Depth

• Width

• Height

A line type that represents an edge that is not directly visible because it is behind or beneath another surface.

• Hidden Line

• Object Line

• Centerline

• Construction Line