MIRRTEXT controls how TEXT is mirrored. The default in AutoCAD® for many years was for it to mirror TEXT like the world is full of ambulance paint job designers. Just make sure to set MIRRTEXT to "0" and be done with it.
A sure sign of an
AutoCAD® novice is
overly complicated drawings. Complicated on many
levels. For example: too many text styles, layers,
dimension styles etc.. And, most often of all -- too
many entities. Now, you might be wondering how on
earth could you have too many entities? You need a
line to draw a line . . . don't you? Yes, more or
less. The "less" is the important part of that
statement. Here are a few rules to keep in
mind:
- use POLYLINES instead of
LINES
- use BLOCKS for repetitive
objects
- use SHAPES for repetitive simple
objects
At first one doesn't think much about the fact
that most of one's time working in
AutoCAD® is spent making
"selection sets", first selecting objects, and then using
the REMOVE and ADD options to modify the selection set.
But you do. Therefore, anything that speeds up the
selection set process has an inordinate effect on
speeding up your work.
After all, why select two or more LINES/ARCS
etc. when you can just select one POLYLINE?!
Why use a half dozen LINES, ARCS etc. when
using a SHAPE instead will save time and drawing
size?
And last, but definitely not least -- why
select possibly hundreds of entities -- when you can
select just one BLOCK? This is much more efficient as far
as making selection sets, and also, everything else being
equal the drawing size will be smaller.
There are, of course, many other advantages to
using POLYLINES, SHAPES and in particular,
BLOCKS.
A certain percentage of idiots in every class/office do not understand the importance of using OBJECTSNAP. From the beginning of my "career" as a Computer Draftsman I took it one step further using what I call "Zen ObjectSnap". Always do the same task in the exact same way. E.g. copying or moving the TEXT entity that makes up a note on a drawing - use the same OBJECTSNAP, from point to point. That way you know that every line of TEXT, every LEADER etc. is in the exact same position in all of your drawings. WARNING: This only works if you do the whole drawing! Even one other CAD person working on one of your drawings can screw this up!
"Previous to the last, was the last previous!"
Eric
Bailey
I am somewhat chagrined to admit that when I was a
beginner in AutoCAD® it was a revelation when it
occurred to me that there was a "ZOOM-Previous" and a
selection set "Previous". This illustrates the fact that it
takes experience to understand all of the possibilities of
"LAST" and "PREVIOUS" -- especially in respect to selection
sets.
-
First of all, there is a "ZOOM-Previous", but not a
"ZOOM-Last" -- because what would be "ZOOM-Last" is of
course "ZOOM-Previous"!
-
"LAST" is used in making selection sets to select
the LAST entity created that is visible in the display
area of the monitor.
-
"PREVIOUS" is similar to "LAST" except it selects
the previous object(s) or, in other words, the previous
selection set.
-
In addition to the basics listed above, there are
many obscure little tricks to learn . . .
-
If, after hitting "Enter", you realize that there
was an entity(s) that you should have REMOVED or ADDED
(or even that you issued the wrong editing command) --
just cancel the command and then hit "Enter" again to
repeat (or enter a new command) your editing command
and "Previous". This will have reselected the Previous
selection set and you will be able to ADD or REMOVE
entities as required.
-
Most importantly and, possibly, the least obvious is
"REMOVE-Previous". For example: MOVE some entities
(this is selection set 'A') on top of several
(hundreds?) other entities. Again, using the MOVE
command, use a window to select selection set 'A' and
the other entities, then issue -- "REMOVE-Previous".
This will remove what you had originally moved
(selection set 'A' ), not everything that you just
selected! This is because a selection set does not
become a "Previous" selection set until the current
command is finished!
-
Editing with GRIPS does not result in a Previous
Selection set, the Former-Previous Selection set is in
affect.
-
A "Previous" after using MATCHPROP does not include
the Source Object, unless you specifically include it
while making the Selection set that will be
MATCHPROP'ed
-
BHATCH does not result in a Previous Selection set,
the Former-Previous Selection set is in affect. However
using the old HATCH command does create a new Selection
set.
-
The DDEDIT command does not result in a Previous
Selection set, the Former-Previous Selection set is in
affect, yet other dialogue commands do create a new
Selection set!
-
MPEDIT: has very interesting characteristics. MPEDIT
creates a Selection set -- but only of the entities
that are already PLINES and only if you answer "Yes" to
the question "Convert lines and arcs to plines ?". In
other words, LINES and ARCS that are changed into
PLINES by the command MPEDIT are not part of the new
Selection set !
-
MIRROR: If you answer "Yes" to the question "Delete
original objects ?" in the MIRROR command the newly
mirrored entities will be selected by "Previous".
WBLOCK: When WBLOCKing entities a "Previous" (after
OOPSing the entities back) will reselect them. This will
enable you to easily ADD or REMOVE entities as required
to redefine the DWG file you have just created -
"Cannot re-enter AutoLISP": This error message after
issuing the SSX command requires the use of "Previous"
in order to do a "work around". Use SSX to select
objects and then issue a LISP routine command NAME,
using "Previous" to select what was selected by SSX.
You may now revise the Selection set using ADD and
REMOVE.
As you can see the permutations are almost endless,
however the main thing to remember is that you must be
aware of how AutoCAD® actually works! Only in this way
will you avoid random lines, arcs, text etc. appearing all
over what should be a pristine CAD drawing.
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Although AutoCAD® usually works logically -- there
are exceptions. For example, one would think that the
selection set option "LAST" would select the last entity
created in the drawing file. However, what it actually does
is select the last entity created that is visible in the
graphics display.
Play with BLOCKs....
Eric Bailey
BLOCKs are one of the most powerful features in
AutoCAD®. It is unfortunate that so little time is
spent exploring their use in schools and offices. When I
was in school it was mentioned in the same context as the
COPY command – mainly as a way of drawing something
once and then reusing it over and over. Specifically, it
was mentioned in concert with the WBLOCK command as a way
to create a block library. A very important feature.
However, the real power inherent in BLOCKs is to use
them as an editing tool. Having INSERTed a number of BLOCKs
into a drawing, you are free to edit, redefine for example,
the BLOCK as required. Of course, in AutoCAD® 2000, you
may do this very easily using the REFEDIT command! XREFs
are a whole other subject (although almost identical to
BLOCKs, XREFs are much more complicated from a CAD-managers
perspective).
Try this exercise: Create a BLOCK consisting of one
vertical line. ARRAY (or COPY etc.) the BLOCK along a line
that represents the finished grade. This creates a simple
"fence". An ugly fence, but a fence. However, because it
was drawn originally by using a BLOCK, you can easily
redefine that BLOCK to create the vertical boards and
horizontal structure of an actual fence, with all
horizontal lines matching, all (standard) details complete.
If you use "BYBLOCK" and "LAYER 0" you may also control the
COLORs, LINETYPEs etc. of your BLOCKs.
In particular, for Beginners, if you open a
drawing that is filled with BLOCKs – do not EXPLODE
them in order to edit them one at a time. First, explore
the options/tools to automate the editing of BLOCKs, e.g.,
REFEDIT, basic redefining, Express/LISP routines that will
SCALE or ROTATE etc. the BLOCKs and/or ATTRIBUTES for
you!
EXPLODE a BLOCK to edit it only as a last resort. In
other words - Play with BLOCKs....
POINT. My point being, do not draw with points. Many people
with little or no training in AutoCAD® think that they
are being clever by using a POINT to draw a "point".
However, a POINT's appearance can be more than just a
"dot".
Points "locked" into a block is a whole other topic
Note that
POINT size is controlled by the variable PDSIZE.
No, it is much safer to just draw a really short line
and make a block out of it. Ideally, draw a line say,
0.00000001 mm long, scale it by 0.001., and create a block
out of it. Remember to set the colour of the LINE to
BYBLOCK. Use MIDPOINT for the insertion point of the BLOCK.
This will plot as a dot no matter what PDMODE is set to.
PDMODE determines the appearance (e.g. line, circle, cross
etc.) that points will have.
NOTE:
Because of variations in computer setups, AutoCAD®
releases etc., please do not assume that all of these tips
will apply to your specific situation.
Please read the
DISCLAIMER.
Click here for Editorials ~ including a number about AutoCAD and Computer Drafting.NOTE: Several AutoCAD Tips and Editorials are exactly the same!
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