Autolisp - Change value in coordinates

[traci_haberghamJQEJT]

Good morning all,

I'm looking to create a command to rule a line either in the x or y direction from the initial point that the user chooses.

I can get the point but I'm unsure on the best way to update the value within the co-ordinates!

What is the best way to add 20000 to the x value of a coordinate?

Thank you

Traci

[tramber · Accepted solution]

I use this :

(defun +x (pt val) (cons(+(car pt)val)(cdr pt)))

It gives :

(+x '(0 0 0) 10) -> (10 0 0)

(+x  pointA  added_value)

(cons(+(car pt)val)(cdr pt))

Is the code. 

[Kent1Cooper · Accepted solution]

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@traci_haberghamJQEJT wrote:

.... from the initial point that the user chooses. ....

What is the best way to add 20000 to the x value of a coordinate?

....

---

(polar UserPoint 0 20000)

or for the Y value instead:

(polar UserPoint (/ pi 2) 20000)

Or:

(mapcar '+ UserPoint '(20000 0 0))

or for the Y value instead:

(mapcar '+ UserPoint '(0 20000 0))

[john.uhden]

@traci_haberghamJQEJT ,

You don't necessarily need AutoLisp to do what you want.

Just make sure that Orthomode is on (F8)
Then pick your starting point,

Then aim your cursor either up/down or left/right and type in the length.

[Sea-Haven · Accepted solution]

This will add a value to the point selected, maybe can be used transparently. 

(mapcar '+ (getvar 'lastpoint) (list 20000 0.0 0.0))

(defun c:20000 ( / )
(command "line" (getpoint "\nPick 1st point "))
(command (mapcar '+ (getvar 'lastpoint) (list 20000 0.0 0.0)) "")
)

There is a way using a reactor that you could type Lxxx and it will draw a line xxx length in X direction.  Maybe better as X1200 then can have Y1000 and so on. Will leave it to others to have a go at modifying code provided. Load the lisp and type X20000 on command line. or X1000 and so on. Note if want decimals must do like this 123-4 use a "-" for decimal point.

[traci_haberghamJQEJT]

That's great, thank you.  It halves the amount of clicks the user has to do.