Arc length dimensions measure the distance along an arc or polyline arc segment.
Typical uses of arc length dimensions include measuring the travel distance around a cam or indicating the length of a cable. To differentiate them from linear or angular dimensions, arc length dimensions display an arc symbol by default.
The arc symbol, also called a hat or cap, is displayed either above the dimension text or preceding the dimension text. The placement of the arc symbol can be specified in the dimension style.
The extension lines of an arc length dimension can be orthogonal or radial depending on the included angle. Orthogonal extension lines are displayed only when the included angle of the arc is less than 90 degrees.
