Constrained linear dimensioning

The Constrained Linear Dimension tool is in the Dims/Notes tool set (all workspaces) and the Basic palette (Spotlight and Landmark workspaces).

Use the Constrained Linear Dimension tool to draw dimension lines that are constrained to the X or Y axis of the plane where the dimension is created. This is different from the Unconstrained Linear Dimension tool, which can draw dimension lines at any angle. In addition to measuring and dimensioning objects, you can use this tool to calculate the horizontal or vertical distance between two or more points in the drawing.

In a 2D view, the dimension line is constrained to be parallel to either the X or Y axis of the active plane. In a 3D view, the dimension line is constrained to the X axis of the plane where it is created, but the plane can have any rotation (similar to the Unconstrained Linear Dimension tool).

If the Snap to Working Plane option on the Snapping palette is enabled, the dimension line is projected to the current working plane, in both 2D and 3D views.

Mode	Description
Constrained Linear	Creates a constrained dimension line with a single measurement
Constrained Chain	Creates a continuous chain of constrained dimension lines
Constrained Baseline	Creates a series of connected constrained dimension lines, starting from an initial base point
Ordinate	Creates a series of constrained ordinate dimensions, starting from an initial base point
Selected Objects	Creates a constrained dimension line for the greatest span of a selected object or group of objects
Preferences	For Constrained Chain mode, specifies whether dimensions are created as a single chain object, or as individual dimension objects; also enables collision control, which automatically spaces text blocks so that they do not overlap
Dimension Standards	To change the dimension standard for new dimensions created in the document, select a standard from the list; select Custom Standards to create or manage custom dimensions (see Using custom dimension standards)