Topic: Calculate the coordinates of the point

[andy_lee]

Dear All

Known  offset value D1 and D2 , Pick 2 line , Calculate the coordinates of the point "P"

Line1 and Line 2 must have a intespoint . if not inters , prompt 
Line1 and Line2 maybe is A portion of a polyline.

Code: [Select]

(setq *D1* 10)
(setq *D2* 15)

(setq L1 (entsel "\n>>>Pick First line :"))
(setq L2 (entsel "\n>>>Pick Second line :"))

......

Thanks for any help !

[andy_lee]

Oh! Post wrong place , Administrator , Please help me  move  it to “AutoLISP (Vanilla / Visual)”  ,Thank you !

[Lee Mac]

• Obtain the endpoints of each selected line
• Calculate the line intersection point (using inters with the end points)
• Calculate a unit vector from the intersection point to the opposite end point of each line
• Scale each vector by the require distance (d1 & d2)
• Add the vectors to obtain the required point.

[andy_lee]

Hi
Lee  Thank you for help!

Sometime the result is wrong. why?

Code: [Select]

(vl-load-com)
(setq *D1* 10)
(setq *D2* 15)
(setq L1(entsel "\n>>>Pick First Line:"))
(setq L2(entsel "\n>>>Pick Second Line:"))
(setq pt1(vlax-curve-getClosestPointTo(vlax-ename->vla-object(car L1))(cadr L1)nil))
(setq pt2(vlax-curve-getClosestPointTo(vlax-ename->vla-object(car L2))(cadr L2)nil))
(setq interpoint
      (inters
          pt1(polar pt1(+(angle(cadr L1)pt1)(* 0.5 pi)) 5.0)
          pt2(polar pt2(+(angle(cadr L2)pt2)(* 0.5 pi)) 5.0)
          nil
       )
)
(setq pt1-1 (polar pt1(angle interpoint pt2) *D1*))
(setq pt2-1 (polar pt2(angle interpoint pt1) *D2*))
(setq p
      (inters
           pt1-1(polar pt1-1(+ (angle pt1-1 pt1) (* 0.5 pi)) 5)
           pt2-1(polar pt2-1(+ (angle pt2-1 pt2) (* 0.5 pi)) 5)
           nil
       )
)



[Hugo]

At with it goes. 

Bei mit geht es.

Code: [Select]

(setq *D1* 10)
(setq *D2* 15)
(setq L1(entsel "\n>>>Pick First Line:"))
(setq L2(entsel "\n>>>Pick Second Line:"))
(setq pt1(vlax-curve-getClosestPointTo(vlax-ename->vla-object(car L1))(cadr L1)nil))
(setq pt2(vlax-curve-getClosestPointTo(vlax-ename->vla-object(car L2))(cadr L2)nil))
(setq interpoint
      (inters
          pt1(polar pt1(+(angle(cadr L1)pt1)(* 0.5 pi)) 5.0)
          pt2(polar pt2(+(angle(cadr L2)pt2)(* 0.5 pi)) 5.0)
          nil
       )
)
(setq pt1-1 (polar pt1(angle interpoint pt2) *D1*))
(setq pt2-1 (polar pt2(angle interpoint pt1) *D2*))
(setq p
      (inters
           pt1-1(polar pt1-1(+ (angle pt1-1 pt1) (* 0.5 pi)) 5)
           pt2-1(polar pt2-1(+ (angle pt2-1 pt2) (* 0.5 pi)) 5)
           nil
       )
)



(defun Circle (cen rad)
  (entmakex (list (cons 0 "CIRCLE")
                  (cons 10 cen)
                  (cons 40 rad))))

(Circle p 1)

[Hugo]

When I click on a line in the X-Ref klick I get also an error message   

; error: bad argument value: AcDbCurve 42

[Hugo]

Can wehel help you the lines also in an X-Ref can click.
"Nentsel" does not go unfortunately.   

Thank you   


Kann wehr Helfen das man die Linien auch in einer X-Ref anklicken kann.
"nentsel"  geht leider nicht.

Danke

[andy_lee]

At with it goes. 

Bei mit geht es.

Code: [Select]

(setq *D1* 10)
(setq *D2* 15)
(setq L1(entsel "\n>>>Pick First Line:"))
(setq L2(entsel "\n>>>Pick Second Line:"))
(setq pt1(vlax-curve-getClosestPointTo(vlax-ename->vla-object(car L1))(cadr L1)nil))
(setq pt2(vlax-curve-getClosestPointTo(vlax-ename->vla-object(car L2))(cadr L2)nil))
(setq interpoint
      (inters
          pt1(polar pt1(+(angle(cadr L1)pt1)(* 0.5 pi)) 5.0)
          pt2(polar pt2(+(angle(cadr L2)pt2)(* 0.5 pi)) 5.0)
          nil
       )
)
(setq pt1-1 (polar pt1(angle interpoint pt2) *D1*))
(setq pt2-1 (polar pt2(angle interpoint pt1) *D2*))
(setq p
      (inters
           pt1-1(polar pt1-1(+ (angle pt1-1 pt1) (* 0.5 pi)) 5)
           pt2-1(polar pt2-1(+ (angle pt2-1 pt2) (* 0.5 pi)) 5)
           nil
       )
)



(defun Circle (cen rad)
  (entmakex (list (cons 0 "CIRCLE")
                  (cons 10 cen)
                  (cons 40 rad))))

(Circle p 1)

Hello
I can't see any change,  you just add a test function?

[andy_lee]

• Obtain the endpoints of each selected line
• Calculate the line intersection point (using inters with the end points)
• Calculate a unit vector from the intersection point to the opposite end point of each line
• Scale each vector by the require distance (d1 & d2)
• Add the vectors to obtain the required point.

I can't understand No.3. what is unit vector?

[kdub_nz]

If you consider a vector has a distance and a direction, the direcrion can be expressed by an X distance and a Y distance,
and the hypotenuse of the triangle formed is the vector distance.

A unit vector has the triangle hypotenuse reduced to one unit with the X and Y distances modified accordingly.

This may help :
https://www.khanacademy.org/math/precalculus/vectors-precalc/unit-vectors/v/unit-vector-intro

[Hugo]

Here my test

Code: [Select]

(defun c:Test ( /)
(vl-load-com)
  (setq *D1* (getreal "\nAbstand von Wand D1 eingeben: "))
  (setq *D2* (getreal "\nAbstand von Wand D2 eingeben: "))    
;;(setq *D1* 10)
;;(setq *D2* 15)
(setq L1(entsel "\n>>>Pick First Line:"))
(setq L2(entsel "\n>>>Pick Second Line:"))
(setq pt1(vlax-curve-getClosestPointTo(vlax-ename->vla-object(car L1))(cadr L1)nil))
(setq pt2(vlax-curve-getClosestPointTo(vlax-ename->vla-object(car L2))(cadr L2)nil))
(setq interpoint
      (inters
          pt1(polar pt1(+(angle(cadr L1)pt1)(* 0.5 pi)) 5.0)
          pt2(polar pt2(+(angle(cadr L2)pt2)(* 0.5 pi)) 5.0)
          nil
       )
)
(setq pt1-1 (polar pt1(angle interpoint pt2) *D1*))
(setq pt2-1 (polar pt2(angle interpoint pt1) *D2*))
(setq p
      (inters
           pt1-1(polar pt1-1(+ (angle pt1-1 pt1) (* 0.5 pi)) 5)
           pt2-1(polar pt2-1(+ (angle pt2-1 pt2) (* 0.5 pi)) 5)
           nil
       )
)
(Circle p 10)
);defun


(defun Circle (cen rad)
  (entmakex (list (cons 0 "CIRCLE")
                  (cons 10 cen)
                  (cons 40 rad))))

[Hugo]

Q kdub   

[kdub_nz]

Q kdub   

You have a problem with my response Hugo ??

[Hugo]

Yeah I'm too high for me   


Ja ich das ist zu hoch für mich

[andy_lee]

Here my test

Code: [Select]

(defun c:Test ( /)
(vl-load-com)
  (setq *D1* (getreal "\nAbstand von Wand D1 eingeben: "))
  (setq *D2* (getreal "\nAbstand von Wand D2 eingeben: "))    
;;(setq *D1* 10)
;;(setq *D2* 15)
(setq L1(entsel "\n>>>Pick First Line:"))
(setq L2(entsel "\n>>>Pick Second Line:"))
(setq pt1(vlax-curve-getClosestPointTo(vlax-ename->vla-object(car L1))(cadr L1)nil))
(setq pt2(vlax-curve-getClosestPointTo(vlax-ename->vla-object(car L2))(cadr L2)nil))
(setq interpoint
      (inters
          pt1(polar pt1(+(angle(cadr L1)pt1)(* 0.5 pi)) 5.0)
          pt2(polar pt2(+(angle(cadr L2)pt2)(* 0.5 pi)) 5.0)
          nil
       )
)
(setq pt1-1 (polar pt1(angle interpoint pt2) *D1*))
(setq pt2-1 (polar pt2(angle interpoint pt1) *D2*))
(setq p
      (inters
           pt1-1(polar pt1-1(+ (angle pt1-1 pt1) (* 0.5 pi)) 5)
           pt2-1(polar pt2-1(+ (angle pt2-1 pt2) (* 0.5 pi)) 5)
           nil
       )
)
(Circle p 10)
);defun


(defun Circle (cen rad)
  (entmakex (list (cons 0 "CIRCLE")
                  (cons 10 cen)
                  (cons 40 rad))))

Hi
I can't see any change again，This code applies only to the rectangle
you can draw 2 line test.

[Hugo]

Yes for rectangles, lines and poly is with me.

Then I understand something wrong? 
For X-Ref it is unfortunately not?   


Ja für Rechtecke, Linien und Poly geht es bei mir.

Dann verstehe ich was falsch ?
Für X-Ref geht es leider nicht ?

[andy_lee]

The result only rectangle is right ! because the angle is 90
you can draw 2 line . the angle is not 90. test again

[Hugo]

Hier

[andy_lee]

Hier

The angle is still 90

[Hugo]

OK now I understand.
This is not true.   

[It's Alive!]

If you consider a vector has a distance and a direction, the direcrion can be expressed by an X distance and a Y distance,
and the hypotenuse of the triangle formed is the vector distance.

A unit vector has the triangle hypotenuse reduced to one unit with the X and Y distances modified accordingly.

This may help :
https://www.khanacademy.org/math/precalculus/vectors-precalc/unit-vectors/v/unit-vector-intro

unit vectors have little hats

[kdub_nz]

Yep ... a party hat.


but just to show they are not all frivolous ...

Consider a unit vector with a direction of 30 degrees.

cos(30) is 0.8660 which is the x offset
sin(30) is 0.50 which is the Y offset.

similarly cos(45) and sin(45) are both 0,7071  which is the the x an Y offset from the startpoint.

//------------------

My old math master used to say something like " the universe is made up of circles and triangles"
... I've since come to understand that he wasn't really joking.

[andy_lee]

Still can't understand. my math is so bad.
Math master and Lisp master .please give a fish.
@Lee Mac @ribarm @roy_043  ....

[kdub_nz]

I can't understand No.3. what is unit vector?

You're welcome.

... my math is so bad.

Well, do something about it.


I'm outa here.

[andy_lee]

This I do:
https://www.theswamp.org/index.php?topic=52652.msg575395#msg575395

I want use Lee's method. but I can't understand.

[It's Alive!]

Yep ... a party hat.

Joking aside, thanks for the link