Parts Blocks), Demystified
The
whole topic of parts can be very complicated to some.
In this note I hope to unlock some of the mysteries
and make them easier for you to use.
A
Part is a group of drawing entities that are classed
as a single drawing entity and treated as one. Some
examples may include; North Point, Title Block, Posts
and Bars, Key Map, Notes, Company Logo, and many other
symbols.
To
start with, I need to explain that there are basically
two different types of blocks.
- Internal
-
An internal part can only be found inside of the
current drawing. It is normally generated so you
do not have to redraw the same symbol over again.
The internal part can be inserted many times in
this drawing but can not be used in any other drawing
unless it is converted to an external part, or unless
this drawing is used as a template for another job.
- External - Any drawing on the hard drive can be considered
an external part. An external part can be inserted
into any drawing at any time. You can create an
internal part and then save it as an external part
(as a separate drawing) or you can create an external
part directly from any drawing by selecting what
should form the part.
Creating
Internal Parts
Let
us start by creating an internal part. The first thing
you need to do is draw the objects you wish to create
the internal part from. Normally you would draw all
of your parts at a scale of 1:1 (metric). This way
if you insert it into a drawing at a different scale,
such as 1:200, then the scale factor is very simple
to figure out. In imperial we would draw it at 1"=1'
as the base.
As
an example, you have a 24" x 36" piece of
paper to draw a border on. You have a 1/2" margin
on all sides. So you draw a rectangle exactly 23"
x 35" in size (this is at a scale of 1"
= 1'). Now if you wish to save this border so you
can use it in the current job only, then you would
use the following command. Under the Part pulldown
menu -> Define Part. Here is what you see when
you pick this command,
In
the bottom left you see a white window with a list
of internal parts that already exist in this drawing.
If this is a new drawing then this list may be blank.
If you pick on one of the names in the list then you
can see what this part looks like by looking at the
Preview box on the right. This allows you to check
the current parts so you don't duplicate one by mistake.
In the top left you are asked to fill in the Part
Name that you are creating. In this example I am using
the name BORDER. That means that when I am done this
command, there will be a part called BORDER saved
in this drawing which can be inserted only inside
this drawing. In the bottom right you can pick from
one of three options.
Delete
Defining Objects: This will erase the original
linework you drew when you drew the part you are defining.
Maintain
Objects:
The original linework will not be erased when the
part has been created. Each line is as it was drawn,
separate from each other.
Replace
by Instance:
The original linework will be erased and a copy of
the part will be placed in the drawing in the location
where you drew the original part. The part is treated
as one object and the original individual lines are
now gone.
In
most cases you drew the part as a temporary object
and you don't need it left as you drew it. You will
insert the part where you wish later. So the first
option is most common and is how my example will be
treated.
Once
you type in the part name, pick the OK button to continue.
Next
you will be asked a few questions to completely define
the part. The Insertion Point is the reference location
for placement. In this example of a border I would
prefer to insert it based upon one of the four corners
of the part. To do this I picked or typed in the INT
option which allows me to pick the Intersection of
the corner of the border. Once the insertion point
has been picked, you will then be asked to pick all
of the items that will form the part. Any standard
selection method is allowed. Once you have picked
all of the objects, press Enter to complete the command.
Insertion
base point: INT
of
object:
Select
objects:
1
selected.
Select
objects:
2
selected.
Select
objects:
3
selected.
Select
objects: ENTER
***
3 selected. ***
The
part has now been saved inside the current drawing
- it is now known as an Internal Part. This part can
be used as many times as required in this drawing
only.
If
you already have a part saved by the same name you
are trying to use this time, then you will get this
warning,
If
you answer Yes then the old part will be replaced
by the one you are creating. No takes you back to
the dialogue and cancel aborts the step.
Creating
External Parts
An
external part allows us to use it in any number of
drawings. To create an external part you can do it
one of two ways.
- You
can simply draw your part in a new drawing and when
you are happy with the final product you can save
the drawing. A saved drawing has the extension of
FLX. This would assume that there is nothing else
in the drawing that would interfere with the part
or get inserted with the part, that shouldn't be
there. The downside is that you have to either think
about and create the part before starting your job
or you would have to erase everything that did not
pertain to the part - another waste of time.
- The
best way is to create the external part from your
current drawing, allowing you to continue with the
job but save features as parts so they can be used
in other jobs at other times. To do this go to the
Part pulldown menu -> Write Part File. Next you
will see,
This
is allowing you to choose the location on your computer
where you can save the new part as well as allowing
you to name it. In my example I am saving it in the
Blocks folder and I am calling it BORDER. The FLX
extension is automatically added as this will actually
be a drawing file when completed. Hit the Save button
once you have the name and location set. We also have
the advantage of choosing the file type in the few
cases when you may wish to create a DXF or DWG file
directly. Do this by picking the Save as Type option
and choose the format desired (FLX is the default).
If
you try to save your part over a file that already
exists then you will see the following warning message,
Now
you will see the following,
This
dialogue box allows you to do one of three things
by selecting the buttons on the right.
PART: If you wish to convert an Internal part to an External
part. In other words you have decided that the internal
part would be handy to use in other drawings and you
don't want to recreate it each time. Pick on the part
name found in the list on the left - then pick the
Part button on the right. You are done. The internal
part has now been saved to it's own drawing file (external
part).
ALL: If you wish to save all of the parts out to a drawing
so they could all be accessed in that drawing. This
is a quick way of copying all of the parts out to
a single drawing and then be able to use each part
individually in that one drawing only.
SELECT: This does not allow you to pick from the list but
it does allow you to create an external part by selecting
the objects in the current drawing. This is the same
as the prompts for the internal part (in blue above),
but will save them in the External Part instead.
You
have now created an External Part on the hard drive.
It is saved as an FLX file (unless you picked DXF
or DWG as your file type).
NOTE: If you insert a part called BORDER in your drawing
then create an external part called BORDER which contains
the original part. When you go to insert the external
part later it will give you the following message.
"Part
BORDER references itself!"
This
is because it now has an internal part within an external
part, both with the same name. This is not permitted.
You will have to edit the External part as a drawing
and rename the internal part, or rename the external
part (drawing name) to solve this duplication problem.
Inserting
a Part
Now
that we have looked at the method of creating both
Internal and External Parts, we now need to explore
the different options available for inserting the
Parts into your current drawing.
There
are four commands that allow you to insert parts.
Insert
Part - This
is the most common of the insert commands. When you
pick it the following dialog box comes up.
It
gives you the ability to insert either and External
Part or and Internal Part.
External:
As
with any Windows style dialogue box, you need to set
the directory or folder to Look In:, then pick from
this location to pick the External Part you will insert.
You can also change the file type to DXF or DWG and
insert that file directly. Once selected, hit Open,
and that will return you to the main screen with the
name and location of the Part you are inserting.
Internal:
The
Internal Part option allows you to choose from any
of the Parts already existing in the current drawing.
Pick on the part name on the left, a preview will
apear on the right to help make the choice easier.
Pick on OK when you have picked your Internal Part
and that will return you to the main screen with the
name of the Part you are inserting.
Once
you have chosen the part to insert you then have the
option to choose the Insertion Point, Scale Factor
and Rotation by typing in the numeric value in the boxes provided or by picking the Interactive
check mark to allow you to pick on screen with the
mouse. You can also choose to have the Part Exploded
automatically on insertion. Exploding a part means
that it is no longer treated as one object and each
line that you used to draw it originally, is now available
again as separate objects.
Insert
Quick - Type
the command QINSERT and you will be asked in the command
prompt area for the "Part name:". You can
either type the name of the Internal Part, or type
the full drive/path/file name of the External Part,
or you can respond by typing the "?" which
brings up the dialogue box shown immediately above
under the Internal option. It is meant to be a quick
and shortened insert command mainly for internal parts.
When using the "?" it is the same as the
"Paste Internal Part" command listed below.
After picking the part name, via any of the options
listed, you will then get the same prompts as shown
below in the "Paste Internal Part 1:1" command
to allow you to rotate, scale and insert the part.
Paste
Internal Part 1:1 - Almost the same as "Insert
Quick", this command does not have the command
option and goes directly to the same dialogue as shown
above. It is for Internal Parts only and always uses
the dialogue box. After picking OK you will see on
the command prompt the following options;
Pick
on Rotation and you will see the prompt;
Insertion
point: Rotation
Rotation
angle <0>:
Pick
on Factor and you get the following options allowing
you to determine the size of the Part.
Finally
you use the mouse to pick where the part is to be
inserted.
Merge
External Part 1:1 - This command is actually the
same as the "External Part" selection process
of the "Insert Part" command above. It is
meant as a quick method to insert an External Part
so it has bypassed the option of picking an Internal
Part. Once you choose the External Part to insert
you will then see the same series of Rotation, Scale
and Insertion prompts as shown in the "Paste
Internal Part" command above.
______________________________________________________________
We
have examined how to create both Internal and External
Parts as well as the four methods of inserting these
parts.
The
last section dealing with Parts that we are going
to cover is dealing with the Part Library and it's
options. First you need to understand what a Part
Library is and what it is for. A Part Library deals
with External Parts only. The Library will contain
many External Parts or FLX drawings in a format that
allows you to see the part and some extra textual
data to allow easy identification of the part. You
can add to a library at any time. You can use the
library to quickly group similar symbols and allow
you to quickly insert one of the symbols into your
drawing.
There
are 3 commands that deal with Part Libraries.
Part
Library Setup:
This will create a new Library and allow you to add
symbols to it. In this example I will create a new
library in the following directory C:\MSCAD2002\MSCAD\BLOCK.
The Library will be called TREES.PLB and as you may
have guessed I am going to add all of the FLX files
that are trees, to this library for easy searching.
The command brings up the following dialogue box and
I have set the directory and file name as mentioned.
After
this I pick the Open button and I will be asked;
If
the library does not already exist.
Answer
Yes and you will see the following dialogue box;
This
dialogue helps control what you will see in the Part
Library once it is created. They should all be more
or less self explanatory. They are all covered in
detail in the on-line help file in MSCAD.
Pick
on OK and this dialogue appears;
Simply
put - the parts in the current directory are all list
on the left - you need to pick on each one (Windows
selection methods are valid) and then pick the >
arrow to add them to the library list. Once all of
the desired External Parts (FLX files) have been picked
and moved to the right side, pick the OK button to
finish this command.
Your
Library now exists on the hard drive in the folder
you selected at the start of this command.
Set
Current Library:
This allows you to select which library is current.
Via
the Look In filed you go to the location on the hard
drive where the Part Library is located. Then pick
on the Library name (TREES.plb in this example) and
pick Open. This sets the current library so the next
command will work.
Part
/ Symbol Library:
This allows you to insert a symbol from the current
library.
There
is a button in the bottom right that allows you to
switch over to Quick Mode - if you do then the number
of parts displayed changes as shown below,
The
Extended button returns you to the first screen. Textual
information can be added to the External Part entry
by picking Information and filling out the form. Close
cancels the command. Open allows you to open the FLX
into the CAD program for editing (not used in MSCAD).
Explode option allows the Part to be exploded into
it's original linework automatically upon insertion
if on. The scale Factor and Rotation can be changed
later and are grayed out for now. The Insert button
is the one that allows you to add the chosen part
to the current drawing.
At
this point you are going to see the exact same prompts
as shown above under "Paste Internal Part".
_________________________________________________________________
There
is another topic dealing with some parts that I am
not going to cover here as it is an advanced feature.
The topic is Attributes. Attributes are small additions
to a part to allow automated insertion of text with
prompts to you to control what the text should read
each time. Maybe another technical not in the future
may cover this topic.
This
was a long technical note and it covered a lot of
material. I hope it helps explain all the major options
dealing with Parts.
Quick
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