Dimensions show the geometric measurements of objects, the distances or angles between objects, or the X and Y coordinates of a feature. AutoCAD ® provides three basic types of dimensioning: linear, radial, and angular. Linear dimensions include aligned, rotated, and ordinate dimensions.
You can create dimensions for lines, multilines, arcs, circles, and polyline segments, or you can create dimensions that stand alone.
AutoCAD draws dimensions on the current layer. Every dimension has a dimension style associated with it, whether it is the default style or one you define. The style controls characteristics such as color, text style, arrowheads, and the scale of the elements in a dimension. Dimensions do not support object thickness. Style families allow for subtle modifications to a base style for different types of dimensions. Overrides allow for style modifications to a specific dimension.