These functions can be
used to make changes to the graphical screen. The graphical screen is
the drawing area of AutoCAD.
(grclear)
This function is used to
clean th active view port of the drawing area. The information is not
erased, but made invisible.
If the REDRAW command is
used, then the information is visible again.
(grdraw
<p1> <p2> <color> [<highlight>])
This function is used to
draw a line between the points p1 and p2. The points can be 2D points
and 3D points.
The color argument sets
the color of the line. If the color argument is -1, then the line is
drawn in the color in a complimentary color.
If another vector is drawn
over the same points with the color, then the complete line is made
invisible.
If the highlight argument
is present and unequal to zero, then the line is drawn in a
highlighted format.
(grtext
[<box> <text> [<higlight>])
With this function you can
write text to the screen menu of AutoCAD. I'm afraid screen menus are
no longer used. So forget it.
(grread
[<track>])
With this function you can
read input from devices such as keyboard, digitizer, mouse, etc. But
most of the time GET functions are used.
If a mouse is used, then
this is what could be given back by the GRREAD fucntion:
(3 (-13.9732 13.0249
0.000000))
The first element is the
the code of the device. These are the codes that are available:
2 Keyboard and the ASCII
code of the character.
3 Mouse. The point is put
in a list.
4 Screen menu cell with
the number of the cell.
5 A list of the point for
the drag mode. Only if the TRACK argument is unequal to nil.
6 Button number of the
mouse.
7 Selected item in TABLET
1 menu.
8 Selected item in TABLET
2 menu.
9 Selected item in TABLET
3 menu.
10 Selected item in TABLET
4 menu.
11 Selected item in AUX 1
menu.
12 Point of the mouse.
13 Selected screen menu
item.
(menucmd
<text>)
This is another function
that works with the screen menu. We are not using it. So you can
forget about it.
Exercise
Now we are going to create
an AutoLISP program, that draws circles and lines. The center points
of the circles are picked.
To create the AutoLISP
program the WHILE function is used. Here is the drawing that is
created. Four circles have been drawn. But more circles could be
drawn.
Repetition
Functions
Now we come to the
repetition functions. They are very important. Repetition functions
are often used in AutoLISP programs.
Here they are:
WHILE
Function
(while
(<test> <expression> …)
This
function performs a test at the beginning. If the test gives nil,
then the expressions are evaluated.
Example:
(defun
c:numbr (/ nr)
(setq
nr 1)
(while
(<= nr 5)
(princ
"\nNumber: ")
(princ
nr)
(setq
nr (1+ nr))
)
(princ)
)
(c:numbr)
At
the start of the AutoLISP program the variable NR is given the value
1. The value of the variable is tested at the beginning of the WHILE
function.
As
long as the value is less or equal to five, then the expressions in
the WHILE function are evaluated.
This
is given back by the AutoLISP program:
Number:
1
Number:
2
Number:
3
Number:
4
Number:
5
Repeat
Function
(repeat
<number> <expression> …)
Now
the number of repetitions can be specified.
Example:
(princ
"\n")
(defun
c:repfc ()
(repeat
4
(princ
"-")
)
(princ)
)
(c:repfc)
This
is given back by the AutoLISP program:
----
Foreach
Function
(foreach
<name> <list> <expression> …)
This
function goes through a list and gives every element of the list a
name. The expression is performed for every name.
Example:
(foreach
n (list 1 2 3) (* n 2))
The
AutoLISP line gives back 6. The number 3 is multiplied with 2.
Exercise:
We
have been talking about predicates, test functions and repetition
functions. Here is an exercise to use what has been taught.
Write
the SLINE AutoLISP program. The following prompts will show up:
Command:
SLINE
Color/Linetype/<first
point>: C
Color:
1
Color/Linetype/<first
point>: L
Linetype:
Hidden
Color/Linetype/<first
point>: 100,100
Close/<next
point>: 300,300
Close/<next
point>: C
Command:
We can create AutoCAD
drawings using AutoLISP. Here is an AutoLISP program that does the
job. The name of the program is NEWDR.LSP.
The
AutoLISP Program
(defun c:newdr (/ p1 p2 p3
p4 p5 p6 p7 sd ts ws)
(setvar “cmdecho”
0)
(setq p1 (getpoint
“\nPosition door: “)
sd (getdist
“\nStructural dimension: “)
ws (getdist
“\nWidth style: “)
ts (getdist
“\nThickness style: “)
p2 (polar p1 0
ts)
p3 (polar p2 (/
pi 2) ws)
p4 (polar p3 pi
ts)
p5 (polar p2 0
sd)
p6 (polar p3 0
sd)
p7 (polar p3 (/
pi 2) sd)
)
(command “pline” p1
“w” 0 0 p2 p3 p4 “c”)
(command “copy” “l”
“” p1 p5 “”)
(command “pline” p2
p5 “”)
(command “copy” “l”
“” p2 p3 “”)
(command “pline” p3
p7 “”)
(command “arc” p6
“c” p3 p7)
(command “zoom”
“a”)
(command “zoom”
“0.8x”)
(setvar “cmdecho”
1) (princ)
)
(c:newdr)
Using the program a door
will be drawn. See how the door looks. As you can see. The door has
different sizes and a position.
Copy
The AutoLISP Program
That is so good about the
listing of an AutoLISP program. You can save it on your hard disk and
use it again. Copy the program to a text file.
That is important. When
the listing of an AutoLISP program is saved, it is saved with the
extension LSP. It can be loaded into your CAD program.
Loading
The AutoLISP Program
Let's talk about how to
load an AutoLISP program into the AutoCAD program. That must be done
first before you can use the AutoLISP program.
I will talk about loading
the AutoLISP program into IntelliCAD. Loading it into AutoCAD is done
in the same way. So don't worry.
You are in IntelliCAD.
Click on Tools in the menu. In the pop-up menu click on Load
Application. The Load Application files dialog box is displayed.
In the dialog box click on
the Add File button. You can go to different folders and you can
select the AutoLISP file that you want to load.
Click on the file. And
click on the Open button. You come back into the Load Application
file dialog box. Click in the Load button.
The AutoLISP file is now
loaded into IntelliCAD. And you can start it by typing its name at
the prompt.
Starting
Automatically
Before I talk about the
AutoLISP program, I want to say something about what has been added
to the program. At the end you see:
(c:newdr)
Through that line the
AutoLISP starts as it has been loaded into IntelliCAD. As you can
see. The name of the AutoLISP program is in the line.
Functions
In the AutoLISP program we
find functions. The first function we find it the DEFUN function.
Here is the syntax of the DEFUN function:
(defun <symbol>
<argument list> <expression> ...)
This how the DEFUN
function is used for defining an AutoLISP function. SYMBOL is the
name of the new AutoLISP function.
Arguments
In the argument list you
find all the arguments that the new AutoLISP function needs to run
properly. If not there, then an error occurs.
Local
Variables
In the argument list you
can find a slash. After the slash comes a list of variables. Those
variables are local variables.
The local variables only
have a value in the function. Outside the function they have no
value. Or the value of them is nil.
If no argument list is
given then the symbol of an empty list must be used. This is how that
symbol looks like: ().
Variables that are not
defined as local have a value outside the function. They have a value
when the function is no longer running.
Here are some examples:
(defun funct (x y) – the
function has two arguments
(defun funct (/ a b) –
the function has two local variables
(defun funct (z / a) –
the function has no argument and one local
variable
(defun funct () - the
function has no arguments
In the AutoLISP function
the GETPOINT and GETDIST functions are used. To get information. In a
separate chapter we talk about the functions.
As you can see. AutoCAD
commands were used in the AutoLISP program. I will talk about using
AutoCAD commands in another report.
Exercise
You now have seen how an
AutoLISP program is created. You have seen how distances can be
entered and how AutoCAD commands are used.
Go ahead. Write your own
program. This time the program is going to draw a house. Enter the
sizes of the house.
Arithmetic
Functions
That is important. In an
arithmetic function the mathematical symbol always comes before the
arguments.
(+
<number> <number> ...)
The plus sign is a
mathematical symbol.
Examples:
Function Gives back
(+ 1 2) 3
(+ 12 13) 25
(+ 1 2 3 4 5) 15
(-
<number> <number> ...)
Examples:
Function Gives back
(- 50 40) 10
(- 40 30 5 0) 5
(- 10 20) -10
(*
<number> <number> ...)
Examples:
Function Gives back
(* 2 3) 6
(* 12 15 2) 360
(* 3 -4.5) -13.5
(/
<number> <number> ...)
Function Gives back
(/ 100 2) 50
(/ 100 2.0) 50.0
(/ 100 20 2) 5
(1+
<number>)
Example:
Function Gives back
(1+ 5) 6
(1-
<number>)
Example:
Function Gives back
(1- 10) 9
(abs
<number>)
This function gives the
absolute value of the number. The number can be a real number of an
integer.
Examples:
Function Gives back
(abs 100) 100
(abs -97.25) 97.25
(max
<number> <number> ...)
This function gives back
the number that is the maximum of all the numbers. The number can be
a real number or an integer.
Examples:
Function Gives back
(max 12 20) 20
(max 5,5 7) 7
(min
<number> <number> ...)
This function is the
opposite of the previous function. Now the minimum number is given
back. The number can be a real number or an integer.
Examples:
Function Gives back
(min 4.07 -144) -144
(min 88.5 19 5) 5
(gcd
<number> <number>)
Now we are going to do a
complicated calculation.With this function the greatest common
divisor is found. The numbers are integers.
Examples:
Function Gives back
(gcd 81 57) 3
(gcd 12 20) 4
(rem
<number> <number> ...)
This function calculates
how much remains after a division. The numbers can be integers and
real numbers.
Examples:
Function Gives back
(rem 42 12) 6
(rem 9 4) 1
(exp
<number>)
This function raises e to
the mach of the number. The number can be an integer as a real
number. The result is always positive.
Examples:
Function Gives back
(exp 1) 2.71828
(exp 2.2) 9.02501
(exp -0.4) 0.67032
(expt
<base> <exponent>)
Now the base number is
raised to the mach of the exponent number. The base and the exponent
can be integers and real numbers.
Examples:
Function Gives back
(expt 2 4) 16
(expt 3.0 2) 9.0
(sqrt
<number>)
This function calculates
the square root of the number. The number can be an integer as well
as a real number.
Examples:
Function Gives back
(sqrt 9) 3
(sqrt 2.0) 1.41321
(log
<number>)
This function gives as
result the natural logarithm of the number. The number can be an
integer as well as a real number.
Examples:
Function Gives back
(log 4.5) 1.50408
(log 1.22) 0.198851
pi
This is no function but a
constant number. The value of the number is 3.1415926.
Geometric
Functions
(cos
<angle>)
This function calculates
the cosinus of an angle. The angle is expressed in radians.
Examples:
Function Gives back
(cos 0) -1
(cos pi) 1
(sin
<angle>)
The same as before. Except
this time the sinus of an angle is calculated. The angle is expressed
in radians.
Examples:
Function Gives back
(sin 1.0) 0.841471
(sin 0,0) 0.0
(atan
<number> [<number>])
If the second number is
not present, then the function gives back the tangent of the first
number in radians.
The number of the angle
can be between pi and -pi,
Examples:
Function Gives back
(atan 0.5) 0.463648
(atan 1.0) 0.785398
(atan -1.0) -0.785398
If the second number is
present, then the function gives back the inverse tangent of the
quotient of the two numbers.
Examples:
Function Gives back
(atan 2.0 3.0) 0.588003
(atan -2.0 3.0) -0.68003
(atan -2.0 -3.0) -2.55359
(atan 1.0 0.0) 1.570796
(atan -0.5 0.0) -1.570796
(angle
<point1> <point2>)
The function calculates
the angle of the straight line going from point1 to point2. It
calculates the angle between the line and the active UCS.
UCS stands for User
Coordinate System. And the angles are measured counter clockwise. And
the angle is given in radians.
Examples:
Function Gives
back
(angle '(1.0 1.0) '(1.0
4.0)) 1.5708
(angle '(5.0 1.33) '(2.4
1.33)) 3.14159
(distance
<point1> <point2>)
The function gives the
distance between the two points. The distance is given in screen
units.
If the value of the
FLATLAND system variable is unequal to zero, then 2D points are
expected. If a 3D point is used, then the Z value is ignored.
Examples:
Function Gives back
(distance '(1.0 2.5 3.0)
'(7.7 2.5 3.0)
) 6.7
(distance '(1.0 5.0)
'(1.0 15.0)
) 10.0
(inters
<point1> <point2> <point3> <point4> [<on>])
The function calculates
where the lines between point 1 and point 2 and point 3 and point 4
cross. A point is given back.
When the optional argument
ON is present and nil. Then the two lines are considered to be
infinite.
Examples:
(setq p1 (list 1.0 1.0)
p2 (list 9.0 9.0)
p3 (list 4.0 1.0)
p4 (list 4.0 2.0)
)
Function Gives back
(inters p1 p2 p3 p4) nil
(inters p1 p2 p3 p4 T)
nil
(inters p1 p2 p3 p4
nil) (4.0 4.0)
(polar
<point> <angle> <distance>)
This function gives as a
result a point that is under an angle from the point that has been
given and on the distance.
Example:
Function Gives back
(polar '(1.0 1.0) 0 4.0)
(5.0 1.0)
(osnap
<point> <mode>)
Depending on the value of
the text of the mode a point is calculated. These are the modes there
are:
Mode Description
”
nea” Nearest snap
”
endp” Endpoint snap
”
midp” Midpoint snap
”
centre” Center snap
”
perp” Perpendicular
snap
”
tan” Tangent snap
”
quad” Quadrant snap
”
int” Insertion point
snap
”
pnt” Point Snap
”
int” Intersection
snap
Example:
Function
(setq pt (osnap pt “nea”))
Exercises
1. Write the following
arithmetic functions:
- 12 plus 13
- 8 times 5
- 200 divided by 4
- What is maximum of 12,
25 3 2, 94?
- What is the greatest
common divisor of 256 and 326?
- What is the 8th
power of 3?
2. Using geometric
functions:
- What is the angle of a
horizontal line? From left to right and from right to left.
- What is the distance
between the points 10,20 and 40,50?
- What point is found
starting in punt 10,20 and under an angel of 45 degrees and over a
distance of 25?
Let's start with AutoLISP.
It is used for writing programs for AutoCAD and CAD programs similar
to AutoCAD. IntelliCAD is such a program.
With AutoLISP you can
write programs that perform tasks and calculations automatically.
AutoLISP is a dialect of
the programming language LISP. LISP has been developed by John
McCarthy in the nineteen fifties.
LISP is the second higher
programming language after FORTRAN. In the nineteen eighties LISP
became really popular.
LISP was used for
developing scientific systems, the so called Expert Systems, and
systems for artificial intelligence.
Now we not only have LISP.
There are also many dialects of LISP. Some dialects are InterLISP,
MacLISP, ZetaLISP, CommonLISP, and SCHEME.
AutoLISP is also a dialect
of LISP and it is based XLISP ODF David Bentz. AutoLISP looks very
much like CommonLISP.
The name LISP comes from
“LISt Programming” or LISt Processing”. It is also called “Lots
of Insane Stupid Parenthesis”.
The
Introduction Of AutoLISP
In AutoLISP you can write
programs and functions that can be used in the AutoCAD program and
CAD programs that are alternatives of AutoCAD.
Similar
Programs
Autodesk started with the
introduction of AutoLISP. They praised the:
- Flexibility
- Simplicity
- Interpretation
AutoLISP is flexible,
because you define functions and programs in many ways. And variables
can have many values.
AutoLISP is simple,
because it is easy to learn. Of the higher programming languages
AutoLISP is the easiest one to learn.
You can type an expression
on the command prompt and right away you get to see the result. That
is not complicated.
AutoLISP is being
interpreted instead of being compiled. The advantage is that errors
in the program can be found right away.
AutoLISP
As A Tool
AutoLISP can be used as
you are drawing in AutoCAD or an alternative CAD program. It can be
used for making calculations. Or store data in memory.
Here is an example.
Suppose you want to insert a block. And you want to insert it with a
scale factor of three divided by seven.
The INSERT command is
used. These are the prompts that show up at the command prompt:
- Command:
- Blockname:
- Insertion point:
- X scale factor:
- Y scale factor:
- Rotation angle:
We fill in the name of the
block and we pick a point. That point is the insertion point. Now we
must enter the scale factor.
We know the scale factor
is three divided by seven. We could calculate what the value is and
use the number.
The exact value is
0.4285714285714286. Maybe you round the value up to 0.43. But if you
round it up, you do not get an exact value.
There is another way. It
is the AutoLISP way. If you follow that way, you will use the exact
value of the calculation.
At the prompt, where is
asked for the X value, enter (/ 3.0 7.0). AutoLISP calculates the
value and gives it back to the command.
Concepts
In AutoLISP there are the
following concepts:
- Atoms
- Symbols
- Strings
- Real numbers
- Integers
- Subrs (built in
functions)
- File descriptors
- AutoCAD entity names
- AutoCAD selection sets
- Lists
A symbol is a variable in
which data is stored. Use a name that says something about the data
that is stored in the symbol.
Example:
p1 - point
e1 - entity
A string is a text. In
AutoLISP a string has got quotes. Here is an example of a string as
is used in AutoLISP.
“
This is a string”
Real numbers have a value
behind the point. Here are some real numbers:
- 3.24
- 14.9
- 15.0
An integer is a number
without a part behind the point. Here are integers:
- 23
- 10
Subrs or built in
functions are used by AutoLISP. They perform an action. Here are two
examples:
+ - count
/ - divide
If you work with external
files in AutoLISP, then
file descriptors are used.
With the file descriptor the external file is specified.
Here is how a file
descriptor may look:
<file #E814>
In an AutoCAD drawing you
can find a lot of entities. Every line, circle, block, etc. is an
entity.
These entities have a
name. This is how the name of an entity may look:
<Entity name: 60000014>
In AutoCAD you may find
selection sets. Selection sets are created by AutoLISP. They are
named like this:
<Selection set:5>
These are the atoms of
AutoLISP. But AutoLISP is also having lists. A list is a group of
elements between brackets.
This is how a list may
look:
- (A B C)
- (1 2 (3 4) 5)
A point is a list too. You
can have 2D points and you can have 3D points. This is how they may
look:
- 2D point: (10 20)
- 3D point: (10 20 30)
The numbers in the list
for the point stand for the X value, the Y value, and the Z value.
Only 3D points also have a Z value.
Functions
In AutoLISP there are a
lot of functions. We have used a function as we were calculating a
value for the INSERT command.
The function was (/ 3.0
7.0). Let's be more specific:
(/ 3.0 7.0) - list
/ - built in function
3.0, 7.0 - real numbers
/, 3.0, 7.0 - atoms
A call to a function is
done with a list. You have seen what list has been used here. The
first element is the symbol of the function.
The symbol of the function
is the built in function. It is a dash. We have got a prefix
notation. The symbol comes first.
You will find more
functions in this book. They are all explained. I will not give you
any more examples of functions.
Storing
Data
We have used a function
with the INSERT command. But the result of the function was not
stored in the CAD program.
We can store data in the
CAD program. The data is stored in a symbol. That is done with the
SETQ function. Here is how it is done:
(setq vl 5)
The symbol VL gets the
value five.
But if we use a function
for a calculation, then the function gives back a value too. And we
store that value in a symbol.
Here is what we can do
with the function that we used with the INSERT command:
(setq dv (/ 3.0 7.0))
Now the value of three
divided by seven is stored in the symbol DV.
Getting
A Value
You have stored value in
symbols. And now you want to know the values of the symbols. That is
easy. Put an exclamation mark in front of the symbol.
We have used the SETQ
function like this:
(setq vl 5)
To find the value that is
stored in the symbol VL we enter “!vl” at the command prompt. And
five is given back.
You could also enter at
the command prompt:
(eval vl)
That function also gives
back five.
Lexical
Appointments
We were talking about
AutoLISP. You saw the start of programming in AutoLISP. But there are
some appointments to follow.
- For programing in
AutoLISP lowercase characters and uppercase characters can be used.
The use of lowercase characters is preferred.
- Symbol names can contain
all characters except:
(
)
.
'
“
;
- The following characters
end a symbol name:
(
)
'
“
;
(space)
(end of line)
- Symbol names and
function names cannot start with a number.
- Texts are enclosed in
quotes
- AutoLISP works with
control codes. The following control codes are available:
\\ \ character
\e escape
\n new line
\r return
\t tab
\nnn character nnn
- You can place comments
in an AutoLISP program by placing a semi colon in front of the
colon. The AutoLISP program will ignore the comment.
- For symbols use a name
of two characters. For functions use a name of five characters. To
save computer memory.
Exercises
1. Is (1 4 “hallo”) a
list?
2. Is '(1 2 3)' a list?
3. Is 21 a symbol?
4. How many elements has
the list (1 45 (“this” “is”) “a text”)?
5. What is the integer of
3.1536?
6. What is the integer of
3.0?
7. Is point.1 a symbol?
8. Is point_1 as symbol?
9. What is the result of
(setq ct 56 pt 23)
10. What character is
placed in front of a symbol to get the value of the symbol?
You know about arrays. You
have arrays in Visual Basic, in C++, and many other programming
languages. But AutoLISP?
OK. Let me be very clear.
There are no arrays in AutoLISP. But. In AutoLISP. Can you store
values that are related?
Oh yes. You can. But is is
done in a different way. It is not done in an array. It is done in a
list. AutoLISP works with lists.
Arrays
Let me be very clear.
Let's start with an array. I start with a one dimensional array. Here
is the array:
You find the following
values in the array.
10, 20, 30, 40
So in this one dimensional
array you find four values.
-
|
|
1
|
2
|
3
|
|
1
|
10
|
11
|
12
|
|
2
|
20
|
21
|
22
|
|
3
|
30
|
31
|
32
|
Above you see a two
dimensional array. It consists of three rows and three columns. The
rows and the columns have been numbered.
You find the following
values in the array.
10, 11, 12, 20, 21, 22,
30, 31, 32
So in this array you find
nine values. If you want to specify the first value in the second
row, then you take this:
array (2,1)
Lists
In AutoLISP we don't have
arrays. In AutoLISP we have lists. And like arrays. You have to store
all the values in the list.
Let's take a list with the
values from the one dimensional array. This is how the list looks.
(10 20 30 40)
But we need to store all
the values in the list. This is how we can do it. The name of the
list is LS.
(setq ls (list 10 20 30
40))
The list is stored in the
variable LS. And that is done with the SETQ function. The LIST
function is used to add all the values.
We want to retrieve the
values of the list. Suppose we want to find the first value of the
list. This is how it is done.
(setq v1 (nth 0 ls))
The number of the first
value is zero. The number of the next value is one. Etc. So the
number of the last value is three.
OK. Let's make things a
little complicated. You saw a two dimensional array. Can we store it
in a list in a two dimensional way?
Yes. You can. Of course.
You could all the values of the array in a list. But you can also do
it in a two dimensional way.
Take the values of each
row of the list in a list. This is how it is done:
(setq l1 (list 10 11 12)
l2 (list 20 21 22)
l3 (list 30 31 32)
)
Now we have created three
lists. We have created l1, l2, and l3. We turn them into one list.
See how it is done.
(setq ls (list l1 l2 l3))
If you enter !ls in
AutoCAD, then this is given back by the program:
((11 12 13) (21 22 23) (31
32 33))
Nice. But how can we
retrieve the values in the list? Suppose want to know the first value
that is in l2. How do we do that?
This is how it is done. We
enter at the command prompt:
(setq vl (nth 0 (nth 1
ls)))
First we find the second
list in the ls variable. And then we take the first element of the
second list. Do you see?
Three
Dimensional Lists
Sure. You want to confuse
me. You want to make my life very difficult. Now you want to know
about three dimensional arrays.
You want to know how you
can specify three dimensional arrays in a list. Sorry. I don't need a
psychologist now.
After telling you about
two dimensional arrays and how their values can be put in a list. I
think a three dimensional array is very clear
Arrays
And Lists
There more functions that
have to do with lists. But I'm not going to explain them. I just
wanted to talk about arrays and lists.
Something
Completely Different
Here is something
completely different from what you normally read in this blog. It is
an imagination.
Imagine this. One day you
wake up and you are a millionaire! Look at how different your life
will be:
- You
no longer have to worry about your debts, bills, and slaving for
money.
- You
can spend your time doing things you love, spend your time with your
beloved family and friends.
- You
no longer have to worry about money or have to be poor again. Never
again living the life you used to have.
Do you want to be a
millionaire? Make your dream lifestyle came true. Here's your chance
to be a millionaire. Check this out.
Wake Up Millionaire:
http://l1nk.com/rfbzla
To Your Success
Free
AutoLISP Course
Sorry. This offer is only
for my readers from Malaysia. I want to give an AutoLISP course to
them. Free of charge.
I have more than 900
readers. The majority of them is from the USA. More than 500. But I
also have readers from Malaysia. About 120.
I don't know what my
readers from Malaysia are doing. Are they with an engineering firm or
architecture? Or just interested in AutoLISP?
I offer them a free
AutoLISP course. It works like this. You let me know if interested
and I'll come to your place.
I will give the AutoLISP
course at your office. Your people can attend the AutoLISP course.
The course consist of 15 lessons.
The first ten lessons are
about AutoLISP. All the functions of AutoLISP are explained and there
is talked about the system variables.
During the last five
lessons we are going to write an AutoLISP program. The people
attending the course come with a wish.
That is why this offer is
only for my readers from Malaysia. I live in Malaysia. And I do not
see how I could travel abroad.
The AutoLISP course is
completely free. I will not charge you for the course. But I will ask
you to refund my travel expenses.
The people attending the
course will get an e-book about AutoLISP. The e-book is a PDF file.
What is said in the course, can be found in the book.
The
Main Part Of The AutoLISP Program
Every AutoLISP program has
got a main part. You can recognize that part. It has C: in the
function name.
Here is the main part:
(defun-c:drwpl-(/-ct-ls-et-sp)
---(start)
---(drlns)
---(setq-ct-T)
---(while-ct
------(setq-ls-(fndet)
------------et-(nth-0-ls)
------------sp-(nth-1-ls)
------)
------(if-(null-et)
---------(setq-ct-nil)
---------(progn
------------(delpl)
------------(drwpl-et-sp)
---------)
------)
---)
---(endpr)
)
In the second post of this
AutoLISP program I was talking about the functions of the program.
This is what I wrote:
Function Action
START Setting the
limits, erasing everything in the screen, setting the snap and
grid, zooming out of the screen
DRLNS Drawing four lines
FNDET Finding line or
polyline entity
DELPL Delete polyline
DRWPL Draw polyline, no
intersection with other line
DPLIP Draw polyline,
intersection with other line
ENDPR Ending of the
program
You will find all
functions mentioned in the main part of the AutoLISP program. A call
is made to these functions.
Something else. In the
main part of the AutoLISP program is a WHILE loop. There is a
repetition in the AutoLISP program.
When the program is
running there is asked to select a line. That question is repeated
all the time. Until no line is selected.
This is how it is done:
(setq ct T)
(while ct
(setq ls (fndet)
et (nth 0 ls)
sp (nth 1 ls)
)
(if (null et)
(setq ct nil)
; The AutoLISP program
draws a polyline
)
)
The CT variable is
introduced. The variable gets the value true. As long as the value is
true, the loop continues.
A call is made to the
FNDET function. In that function there is asked to select a line. But
no selection can be made.
The user clicks the right
mouse button if he no longer wants to select a line in the screen.
Then the values of ET and SP are nil.
The value of the ET
variable is checked. If it is nil, then the CT variable gets the
value nil too. And the WHILE loop terminates.
OK. Now I have told you
everything about the AutoLISP program for drawing a polyline. I trust
I have been clear enough.
Something
Completely Different
Here is something
completely different from what you normally read in this blog. It is
an imagination.
Imagine this. One day you
wake up and you are a millionaire! Look at how different your life
will be:
- You
no longer have to worry about your debts, bills, and slaving for
money.
- You
can spend your time doing things you love, spend your time with your
beloved family and friends.
- You
no longer have to worry about money or have to be poor again. Never
again living the life you used to have.
Do you want to be a
millionaire? Make your dream lifestyle came true. Here's your chance
to be a millionaire. Check this out.
Wake Up Millionaire:
http://l1nk.com/rfbzla
To Your Success
Free
AutoLISP Course
Sorry. This offer is only
for my readers from Malaysia. I want to give an AutoLISP course to
them. Free of charge.
I have more than 900
readers. The majority of them is from the USA. More than 500. But I
also have readers from Malaysia. About 120.
I don't know what my
readers from Malaysia are doing. Are they with an engineering firm or
architecture? Or just interested in AutoLISP?
I offer them a free
AutoLISP course. It works like this. You let me know if interested
and I'll come to your place.
I will give the AutoLISP
course at your office. Your people can attend the AutoLISP course.
The course consist of 15 lessons.
The first ten lessons are
about AutoLISP. All the functions of AutoLISP are explained and there
is talked about the system variables.
During the last five
lessons we are going to write an AutoLISP program. The people
attending the course come with a wish.
That is why this offer is
only for my readers from Malaysia. I live in Malaysia. And I do not
see how I could travel abroad.
The AutoLISP course is
completely free. I will not charge you for the course. But I will ask
you to refund my travel expenses.
The people attending the
course will get an e-book about AutoLISP. The e-book is a PDF file.
What is said in the course, can be found in the book.
The
DPLIP Function
This
function is long. And it is also a little bit complicated. But you
will understand the function. I hope.
Here
is the function:
(defun-dplip-(et-sp-ss-/-e1-el-ip-p1-p2-p3-p4)
---(setq-el-(entget-et)
---------p1-(cdr-(assoc-10-el))
---------p2-(cdr-(assoc-11-el))
---)
---(setq-e1-(ssname-ss-0))
---(if-(equal-et-e1)
------(setq-e1-(ssname-ss-1))
---)
---(setq-el-(entget-e1)
---------p3-(cdr-(assoc-10-el))
---------p4-(cdr-(assoc-11-el))
---)
---(if-(or-(=-(angle-p1-p2)(angle-p1-p3))
-----------(=-(angle-p1-p2)-(angle-p2-p3))
-------)
------(setq-ip-p3)
------(setq-ip-p4)
---)
---(if-(=-(+-(distance-p1-sp)
-------------(distance-sp-ip)
----------)
----------(distance-p1-ip)
-------)
------(command-"pline"-p1
-----------------------"w"
-----------------------2.5
-----------------------2.5
-----------------------ip
-----------------------""
------)
------(command-"pline"-p2
-----------------------"w"
-----------------------2.5
-----------------------2.5
-----------------------ip
-----------------------""
------)
---)---
)
We
give an entity to the function together with the selection point and
the selection set that was found in the previous function.
Finding
Two Points Of The Line
We
want to find the two points of the entity. The entity is a line. This
is how we find the two points of trhe line.
(setq-el-(entget-et)
p1-(cdr-(assoc-10-el))
p2-(cdr-(assoc-11-el))
)
Finding
The Other Line
Another
line is coming to the line that we have selected. We want to know
what that line is. It is in the selection set.
There
are two entities or two lines in the selection set. We take the first
entity of the selection set.
We
see if it is the same as the entity that was given to the function.
If it is, then we take the second entity of the selection set.
Here
are the programming lines:
(setq-e1-(ssname-ss-0))
(if-(equal-et-e1)
(setq-e1-(ssname-ss-1))
)
Now
we have the line that is drawn against the line that has been
selected. We find the points of that line. Here is how.
(setq-el-(entget-e1)
p3-(cdr-(assoc-10-el))
p4-(cdr-(assoc-11-el))
)
The
Point On The Selected Line
Now
we need to find what point is on the line that has been selected. We
check the angles. Here is how it is done.
(if
(or (= (angle p1 p2)(angle p1 p3))
(=
(angle p1 p2)(angle p2 p3))
)
(setq
ip p3)
(setq
ip p4)
)
Now
we know the two points of the line that has been selected. And we
know the point of the other line that is on the line.
How
The Polyline Is To Be Drawn
Now
we must figure out how a polyline is to be drawn. We must figure out
between what points the polyline must be drawn.
We
know. The polyline is drawn to the point of the other line that is on
the selected line. But from where is it drawn?
Is
it drawn from point P1 or is it drawn from point P2. The points P1
and P2 are from the selected line.
It
is quite simple to find out between what points the polyline must be
drawn. We look at the distances.
There
is the distance between P1 and the selection point and the distance
between the selection point and the point of the other line.
If
the total of those distances are the same as the distance between P1
and the point of the other line, then we know.
Then
the polyline is drawn from point P1 to the point of the other line.
Otehrwise it comes from point P2.
Here
are the lines of the AutoLISP program.
(if
(= (+ (distance p1 sp)
(distance sp ip)
)
(distance
p1 ip)
)
(command
"pline" p1
"w"
2.5
2.5
ip
""
)
(command
"pline" p2
"w"
2.5
2.5
ip
""
)
)
Next
Post
In
the next post I'm going to talk about the main part of the AutoLISP
program. And then I'm done talking about this AutoLISP program.
Something
Completely Different
Here is something
completely different from what you normally read in this blog. It is
an imagination.
Imagine this. One day you
wake up and you are a millionaire! Look at how different your life
will be:
- You
no longer have to worry about your debts, bills, and slaving for
money.
- You
can spend your time doing things you love, spend your time with your
beloved family and friends.
- You
no longer have to worry about money or have to be poor again. Never
again living the life you used to have.
Do you want to be a
millionaire? Make your dream lifestyle came true. Here's your chance
to be a millionaire. Check this out.
Wake Up Millionaire:
http://l1nk.com/rfbzla
To Your Success
Free
AutoLISP Course
Sorry. This offer is only
for my readers from Malaysia. I want to give an AutoLISP course to
them. Free of charge.
I have more than 900
readers. The majority of them is from the USA. More than 500. But I
also have readers from Malaysia. About 120.
I don't know what my
readers from Malaysia are doing. Are they with an engineering firm or
architecture? Or just interested in AutoLISP?
I offer them a free
AutoLISP course. It works like this. You let me know if interested
and I'll come to your place.
I will give the AutoLISP
course at your office. Your people can attend the AutoLISP course.
The course consist of 15 lessons.
The first ten lessons are
about AutoLISP. All the functions of AutoLISP are explained and there
is talked about the system variables.
During the last five
lessons we are going to write an AutoLISP program. The people
attending the course come with a wish.
That is why this offer is
only for my readers from Malaysia. I live in Malaysia. And I do not
see how I could travel abroad.
The AutoLISP course is
completely free. I will not charge you for the course. But I will ask
you to refund my travel expenses.
The people attending the
course will get an e-book about AutoLISP. The e-book is a PDF file.
What is said in the course, can be found in the book.
The
DELPL Function
Now
I'm going to talk about the next function of the AutoLISP program.
I'm going to talk about the DELPL function. Here it is:
(defun-delpl-(/-et-el-tp)
---(setq-et-(entlast)
---------el-(entget-et)
---------tp-(cdr-(assoc-0-el))
---)
---(if-(=-tp-"LWPOLYLINE")
------(command-"erase"-(entlast)-"")
---)
)
The function is used as
the AutoLISP program starts. It deletes a polyline. A call to it is
in the main AutoLISP program.
Working
Of The Function
The
function works like this. The last entity in the drawing is found.
The ENTLAST function is used.
The
type of the last entity is found. If the type is a polyline, the name
is LWPOLYLINE, then it is deleted.
The
polyline is deleted with this programming line:
(command-"erase"-(entlast)-"")
Important
I
told you. As the AutoLISP program works, then the polyline that has
been drawn by the program, is deleted.
Next
Post
I
keep this post short. In my next post I'm going to talk about the
next function. I'm going to talk about the DRWPL function.
Something
Completely Different
Here is something
completely different from what you normally read in this blog. It is
an imagination.
Imagine this. One day you
wake up and you are a millionaire! Look at how different your life
will be:
- You
no longer have to worry about your debts, bills, and slaving for
money.
- You
can spend your time doing things you love, spend your time with your
beloved family and friends.
- You
no longer have to worry about money or have to be poor again. Never
again living the life you used to have.
Do you want to be a
millionaire? Make your dream lifestyle came true. Here's your chance
to be a millionaire. Check this out.
Wake Up Millionaire:
http://l1nk.com/rfbzla
To Your Success
Free
AutoLISP Course
Sorry. This offer is only
for my readers from Malaysia. I want to give an AutoLISP course to
them. Free of charge.
I have more than 900
readers. The majority of them is from the USA. More than 500. But I
also have readers from Malaysia. About 120.
I don't know what my
readers from Malaysia are doing. Are they with an engineering firm or
architecture? Or just interested in AutoLISP?
I offer them a free
AutoLISP course. It works like this. You let me know if interested
and I'll come to your place.
I will give the AutoLISP
course at your office. Your people can attend the AutoLISP course.
The course consist of 15 lessons.
The first ten lessons are
about AutoLISP. All the functions of AutoLISP are explained and there
is talked about the system variables.
During the last five
lessons we are going to write an AutoLISP program. The people
attending the course come with a wish.
That is why this offer is
only for my readers from Malaysia. I live in Malaysia. And I do not
see how I could travel abroad.
The AutoLISP course is
completely free. I will not charge you for the course. But I will ask
you to refund my travel expenses.
The people attending the
course will get an e-book about AutoLISP. The e-book is a PDF file.
What is said in the course, can be found in the book.
