Computer Aided Draughting 419
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d:\N-Design\Des21-1.pm5
1. Set-up the basic parameters for dimensioning. They are,
(a) arrow head size,
(b) arrow head type,
(c) extension line offset, and
(d) placement of dimension text.
2. Identify what to measure–pick the end points, lines, arcs or circles or other points of
existing drawing entities using OSNAP if neccessary.
3. Specify where the dimension line and text are to be located.
4. Approve AutoCAD’s measurements or can type one’s own text.
21.16.3 Linear Dimensions
Command: DIM
Dim: hor/ver/ali/cont/ang/diam/rad/leader
Chose any one based on the requirement (Fig. 21.19)
First extension line origin or return to select: ↵
Select line, arc, or circle: pick
Dimension line location: pick
Dimension text : ↵
Dim: exit
21.16.4 Continuing Linear Dimensions
Often a series of related dimensions must be drawn, sometimes several dimensions are measured
from the same base line; other times one long dimension is broken into shorter segments that
add upto the total measurement. The base line and continue commands are provided to simplify
these operations. Draw the first dimension, using horizontal, vertical, aligned or rotated
commands. Then enter base line or continue. AutoCAD proceeds directly to the “second extension
line origin” prompt, and then asks for the dimension text. The dimension line is placed at the
same angle as the previous dimension.
Fig. 21.20