Draw a specific perimeter

Using R-14, how do I draw a circle or a rectangle with an exact
perimeter?

JPC

 

Press F1 for HELP and read about it.... See Circle or Rectang.

BruceF

 

I realize you can get the circumference/perimeter after you draw with
the area command, however I did not see anything in the help dialog
that tells you how to create a circle/rectangle with a specific
circumference or perimeter. Any further help is appreciated.

JPC

 

Okay... If I understand you correctly then you need to use Absolute
Coordinates then...

For an Rectangle, say you want one that is 50 units long X 75 units High..

You enter your RECTANG command... Pick the First Point... then type in
the following:
@50,75
(the press the Return key)

This @ X, Y works also for things such as lines, plines, etc.

As to a Circle circumference, I don't think AutoCAD has that built into
it. You'll need to do some simple Math to figure this out...

The circumference of a circle can be found by multiplying pi (which is
equal to 3.14) by the diameter of the circle.

So if a circle has a diameter of 4, its circumference is 3.14*4 = 12.56

If you know the radius, the diameter is twice as large.

So work what your Diameter is to be for a given circumference.

BruceF

 

Since I am using R-14 and changing the circumference in the properties
list won't work can you point me to a lisp routine that I can run?

JPC

 

Since I am using R-14 and changing the circumference in the properties

I quickly wrote this up... cut and paste it into a plain Text file and
rename it to:
CircC.lsp


; Draw a Circle with a Given Circumference
(defun C:CircC ( / pt1 pt2 pt3 cclcirc ccldia)

; pi = 3.14159265
; Math Formula is:
; Circle Diameter X pi = Circumference

; Get Circumference
(setq cclcirc (getreal "\nEnter Circle Circumference: "))

; Get Circle Diameter... then divide by 2 to get Radius
(setq cclDia (/ (/ cclcirc 2) pi))

; Pick Circle Center Point
(setq pt1 (getpoint "\nPick Circle Center Start Point: "))

; Calculate 2nd Point for Circle Command
(setq pt2 (polar pt1 (+ 1 (/ pi 2.0)) ccldia))
(setq pt3 (polar pt1 (- 1 (/ pi 2.0)) ccldia))

; Draw Circle
(command "_circle" "2p" pt2 pt3)

) ;defun



IF you want to, you can rename the Lisp File to what ever you want to of
course (I usually keep the command line and lisp file the same). You
can also change the command to fire this up by changing the 'CircC' that
is in the line:
(defun C:CircC ( / pt1 pt2 pt3 cclcirc ccldia)

You MUST keep the prefix '(defun C:' in place.

BruceF

 

Thanks Bruce, it works great! Is seems to default to inch settings. Is
it possible to add a line to allow for foot settings?

JPC

 

Thanks Bruce, it works great! Is seems to default to inch settings. Is

Ah! Silly me...

Make this simple change:

Change the word getreal to getdist. Then you can now enter Feet, Feet +
Inches, or Inches.

GetReal is asking for a REAL number... GetDist is asking for a Distance
(which is what you want). So any valid Distance entry should work.

Regards,

BruceF

 

Works great!! Thanks again.
JPC

 

for a circle

( / perimeter 6.283185307195864)

say the perimeter is 0.1

enter this for the circle radius.

The zero to the left of the dicimal point is required.

someone here could probably show you how to write an AutoLisp macro.

( / 0.1 6.283185307195864)

Bob