topic Re: Create isosceles triangle in Visual LISP, AutoLISP and General Customization Forum

Create isosceles triangle

carlos_m_gil_p — Thu, 07 Oct 2021 16:20:35 GMT

Hello boys.
Could you help me with a lisp, to create an isosceles triangle.
I have a base line that would be the base of the triangle.
And I have a line where the third vertex of the triangle has to pass.
But I need to draw two sides of the triangle that are equal.

I am attaching a dwg file so that you can understand me better.
The cyan lines are what I need to draw, (in the example they are not the same, because I could not make them remain the same in the drawing)

Beforehand thank you very much.

Re: Create isosceles triangle

hak_vz — Thu, 07 Oct 2021 16:46:10 GMT

Command POLYGON (POL) in edge mode with three sides creates perfect isosceles triangle

Re: Create isosceles triangle

john.uhden — Thu, 07 Oct 2021 16:56:36 GMT

1. Draw a vertical line the length of the triangle height.

2. Offset the line half of the base length, once to the left and once to the right.

3. Draw a polyline from endpoint to endpoint to endpoint and close.

4. Erase the lines.

Re: Create isosceles triangle

john.uhden — Thu, 07 Oct 2021 16:58:29 GMT

@hak_vz

Yes, isosceles, but specifically equilateral.

Re: Create isosceles triangle

carlos_m_gil_p — Thu, 07 Oct 2021 17:00:14 GMT

Hi brother.
With the POL command it doesn't work.
The POL command makes equilateral triangles and I need isosceles.
The isosceles triangle has two equal sides and one unequal side.

Re: Create isosceles triangle

hak_vz — Thu, 07 Oct 2021 17:03:05 GMT

Ok working on code

Re: Create isosceles triangle

Kent1Cooper — Thu, 07 Oct 2021 17:56:21 GMT

Try this [in simplest terms, minimally tested]:

(defun C:WHATEVER (/ basesel base base1 base2 basemid peak) (setq basesel (entsel "\nTriangle base line: ") base (car basesel) base1 (vlax-curve-getStartPoint base) base2 (vlax-curve-getEndPoint base) basemid (osnap (cadr basesel) "_mid") peak (car (entsel "\nLine that peak must meet: ")) ) (command "_.line" "_non" basemid (polar basemid (+ (angle base1 base2) (/ pi 2)) 1) "" ); command (setq mid (entlast)) (command "_.line" base1 (inters (vlax-curve-getStartPoint peak) (vlax-curve-getEndPoint peak) (vlax-curve-getStartPoint mid) (vlax-curve-getEndPoint mid) nil ); inters base2 "" ); command (entdel mid) (princ) )

Re: Create isosceles triangle

hak_vz — Thu, 07 Oct 2021 17:48:13 GMT

(defun c:iso_triangle (/ getintersections adoc e c eo co p1 p2 p3 l lo) (defun *error* ( msg ) (if (not (member msg '("Function cancelled" "quit / exit abort"))) (princ) ) (if (and adoc) (vla-endundomark adoc)) (setvar 'cmdecho 1) (princ) ) (defun getintersections (obj1 obj2 / var) (setq var (vlax-variant-value (vla-intersectwith obj1 obj2 1))) (if (< 0 (vlax-safearray-get-u-bound var acExtendThisEntity)) (vlax-safearray->list var) ) ) (setq adoc (vla-get-ActiveDocument (vlax-get-acad-object)) blocks (vla-get-blocks adoc)) (setq e (car (entsel "\nSelect triangle baseline >"))) (setq c (car (entsel "\nSelect line where third points lie >"))) (cond ((and e c) (vla-endundomark adoc) (vla-startundomark adoc) (setq eo (vlax-ename->vla-object e)) (setq co (vlax-ename->vla-object c)) (setq p1 (vlax-curve-getStartPoint eo)) (setq p2 (vlax-curve-getEndPoint eo)) (setq l (entmakex (list (cons 0 "LINE") (cons 100 "ACDbEntity") (cons 100 "ACDbLine") (cons 10 (mapcar '* (mapcar '+ p1 p2) '(0.5 0.5 0.5))) (cons 11 (polar (mapcar '* (mapcar '+ p1 p2) '(0.5 0.5 0.5))(+ (angle p1 p2) (* 0.5 PI)) 1)) ) ) ) (setq lo (vlax-ename->vla-object l)) (setq p3 (getintersections lo co )) (entdel l) (setvar 'cmdecho 0) (command "_.line" "_none" p1 "_none" p3 "") (command "_.line" "_none" p2 "_none" p3 "") (setvar 'cmdecho 1) (vla-endundomark adoc) ) ) (princ) )

Re: Create isosceles triangle

john.uhden — Thu, 07 Oct 2021 17:59:53 GMT

Alrighty then,

This simple one lets you draw the triangle at any angle...

(defun c:isosceles ( / p1 p2 p3 ang ht) (and (setq p1 (getpoint "\n1st end of base line: ")) (setq p2 (getpoint p1 "\n2nd end of base line: ")) (setq ht (getdist "\nHeight of triangle: ")) (setq ang (angle p1 p2)) (setq p3 (polar p1 ang (* 0.5 (distance p1 p2)))) (setq p3 (polar p3 (+ ang (/ pi 2)) ht)) (vl-cmdf "_.pline" "_non" p1 "_non" p2 "_non" p3 "_C") ) (princ) )

Re: Create isosceles triangle

-didier- — Thu, 07 Oct 2021 18:21:48 GMT

Bonjour @carlos_m_gil_p

I propose this lsp with which you only have to write the two lines, (base first, objective second)

I am at your disposal to improve it if necessary (color, layer...)

;| demande sur le forum anglais de carlos.gil.p du 07 octobre 2021 tracé triangle isocèle depuis ligne de base et ligne objectif les deux lignes sont à sélectionner à l'écran https://forums.autodesk.com/t5/visual-lisp-autolisp-and-general/create-isosceles-triangle/m-p/10673622#M421555 |; (defun c:TRIS2L (/ int l1 l2 p1 p2 p3 p4 pmil proj int) (setq oldosmode (getvar "osmode")) (setq l1 (car (entsel "\nBase Line\n"))) (setq l2 (car (entsel "\nLine Object\n"))) (if (and (= "LINE" (cdr (assoc 0 (entget l1)))) (= "LINE" (cdr (assoc 0 (entget l1)))) ) (progn (setq p1 (cdr (assoc 10 (entget l1))) p2 (cdr (assoc 11 (entget l1))) p3 (cdr (assoc 10 (entget l2))) p4 (cdr (assoc 11 (entget l2))) pmil (mapcar '(lambda (a b ) (/ (+ a b) 2.0)) p1 p2) proj (polar pmil (- (angle p1 p2) (/ pi 2.0)) 1) int (inters pmil proj p3 p4 nil) ) (entmake (cons '(0 . "LINE") (mapcar 'cons '(10 11) (list p1 int)))) (entmake (cons '(0 . "LINE") (mapcar 'cons '(10 11) (list p2 int)))) ) (progn (alert "incorrect selection of entities") (setvar "osmode" oldosmode) ) ) ) (prompt "Command Name : TRIS2L TRiangle ISosceles 2 Lines") (princ)

Amicalement

Re: Create isosceles triangle

hak_vz — Thu, 07 Oct 2021 18:30:08 GMT

@john.uhden What is with your Expert elite signature. It shows message "Image doesn't exist or no longer available "

Re: Create isosceles triangle

-didier- — Thu, 07 Oct 2021 18:24:32 GMT

Bonjour @hak_vz

I sympathize with John because putting elite signatures is not very simple!

Amicalemeny

Re: Create isosceles triangle

carlos_m_gil_p — Thu, 07 Oct 2021 18:59:59 GMT

Hello boys how are you.
All the options work very well.
john.uhden In this case I don't know the height, but it may work for another time.
Thank you very much to all.
Thank you for helping me and teaching me every new day more.
Greetings.

Re: Create isosceles triangle

john.uhden — Thu, 07 Oct 2021 19:30:27 GMT

Thanks, @hak_vz. I'm glad you mentioned it.
Back when, @Jeff_M (Jeff Mishler) gave me his avatar to use. So I just
pasted it and changed the name. But not too long ago, the image
(referenced from on-line somewhere) disappeared. And I don't know how to
get one back or use another.