Leaders is a line or spline with arrowhead at one end, and annotations (Mtext, blocks as well as tolerance) at the other end.
Generally, you place an arrowhead at the first point. An annotation, created as dimension text, is placed immediately adjacent to the last point.
Create a Leader Line
You can use LEADER or QLEADER to create a leader and control the appearance. The color of a leader is controlled by the color of the current dimension line. The scale is controlled by the global dimension scale specified on the current dimension style. The appearance of a leader is control by the setting of the first arrowhead on the current dimension style.
Add Text to a Leader
There are two methods to add text to a leader:
When creating text, you can assign the style to an individual character and attach the copies of the current annotation to the leader.
When the value of variable system DIMGAP is negative, the system creates a box next to the text, which the distance between them is determined by the value of DIMGAP.
The text is placed automatically at the endpoint of a leader at the specified value, which is stored in the "Offset from dim line" on the Text tab of Modify Dimension Style dialog box. If the dimension is tolerance, the future control frame is placed at the endpoint of a leader as well. A block is inserted at the specified location with the specified scale value.
To create a leader and an annotation
Choose Dimensions > Leader.
Specify the starting point of the leader.
Specify the endpoint of the leader line segment.
Specify additional leader line segment endpoints.
After you specify the last endpoint, press Enter.
Type the annotation, and press Enter to enter the Next line of annotation text.
Press ENTER to complete the command.
Command line LEADER
Specify the starting point of the leader (A) and the endpoint of the leader line segment (B)
The following picture shows the text is above at the leader. You can set the justification at the Text tab on the Modify Dimension Style.
LEADER: Creates a line that connects annotation to a feature
QLEADER: Creates a leader and leader annotation
DDEDIT: Edits text, dimension text, attribute definitions, and feature control frames
DIMSTYLE: Creates and modifies dimension styles
MTEXT: Creates multiline text
OPTIONS: Customizes the ZWCAD settings
PROPERTIES: Controls properties of existing objects
PURGE: Removes unused named items, such as block definitions and layers, from the drawing
QTEXT: Controls the display and plotting of text and attribute objects
STYLE: Creates, modifies, or sets named text styles
TEXT: Creates a single-line text object
System Variables Reference
DIMASZ: Controls the size of dimension line and leader line arrowheads
DIMCLRD: Assigns colors to dimension lines, arrowheads, and dimension leader lines
DIMLDRBLK: Specifies the arrow type for leaders
DIMSCALE: Sets the overall scale factor applied to dimensioning variables that specify sizes, distances, or offsets
DIMTAD: Controls the vertical position of text in relation to the dimension line
DIMGAP: Sets the distance around the dimension text when the dimension line breaks to accommodate dimension text
FONTALT: Specifies the alternate font to be used when the specified font file cannot be located
FONTMAP: Specifies the font mapping file to be used
MTEXTED: Sets the primary and secondary text editors to use for multiline text objects
QTEXTMODE: Controls how text is displayed
TEXTFILL: Controls the filling of TrueType fonts while plotting and rendering
TEXTQLTY: Sets the resolution tessellation fineness of text outlines for TrueType fonts while plotting and rendering