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RE: Survey Lines on CAD

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I think we are really saying the same thing. @ is used for positions
relative to either the last point or an arbitrary point chosen on the
screen. Absolute measurement assume that all lines are drawn from a datum at
0,0.
In you example, I assume that the first point you ever created was based
upon an absolute location dirived from the origin. You used that to locate
the point in which you wanted to start your new line (thus the ID
command<?>). Everything else became "relative from that point rather than
you trying to find the exact location on screen relative to the origin.
Dennis
-----Original Message-----
From: Roger Turk [mailto:73527.1356(--nospam--at)compuserve.com]
Sent: Thursday, October 08, 1998 9:07 AM
To: seaint(--nospam--at)seaint.org
Subject: RE: Survey Lines on CAD


Dennis Wish wrote:

. > Remember, "@" is used to start from an arbitrary location.

Actually, "@" is from the last point ("lastpoint").  I use it all the time,
rather than calculating actual coordinates, which is a real PITA, in fact,
I can't recall ever using actual coordinates in the 12 years that I have
been using AutoCad.  I also use the "ID" command to get a start point.  For
example, if I know a line starts at a horizontal distance of 13'6-5/8" from
another point and runs for 357.75 inches in a direction of 39deg 41 min, I
type "id" and select the known point, then type
"L<CR>@13'6-5/8<0<CR>@375.75<39d41'<CR>" and I have the line.  "ID" and "@"
are the two most valuable commands that AutoCad has and the least discussed
by Autodesk.

A. Roger Turk, P.E.(Structural)
Tucson, Arizona