Need help with VLISP Interpolation code

(defun c:test (/ pt1 el1 pnt1 pt1 el2 pnt2 len el1a slp d1)

(vl-load-com)

(setq oldsnap (getvar "osmode"));tweak

(setvar "pdmode" 3)

(setq pt1 (getpoint "\nPick point 1: ")

el1 (caddr pt1)

pnt1 (list (car pt1) (cadr pt1) el1)

pt2 (getpoint pt1 "\nPick point 2: ")

el2 (caddr pt2)

pnt2 (list (car pt2) (cadr pt2) el2)

len (distance pnt1 pnt2)

el1a (1+(fix el1))

slp (/ (- el2 el1)(distance pnt1 pnt2))

d1 (/ (- el1a el1) slp)

)

(setq obj (vlax-ename->vla-object

(entmakex

(list

(cons 0 "LINE")

(cons 10 pnt1)

(cons 11 pnt2)

)

)

)

)

(while (

(entmakex

(list

(cons 0 "POINT")

(cons 10 (vlax-curve-getPointAtDist Obj d1))

)

)

(setq d1 (+ d1 (/ 1 slp)))

)

(setvar "osmode" oldsnap)

(princ)

)

My suggestion don't reinvent the wheel theres some free/cheap contour software out there just look for it and it does a lot more.

I need help working on my code. It was taken from another thread.

 

The point of this LISP routine is to help me

interpolate points

between two known points so that I can come in and draw

contour lines

.

 

Here are my goals

:

*Change the routine to make a point every 5 ft of elevation (65, 70, 75, etc) instead of every 1 ft. It must be every five relative to 0. It cannot be relative to one another. Example: 163, 168, 173

 

Here's the code:

Maybe you should contact lpseifert on this thread: http://www.cadtutor.net/forum/showthread.php?44496-Interpolation-Lisp-Needed&highlight=pt1+el1+pnt1+pt1+el2+pnt2+len+el1a+slp+d1%29

It is his code you want to change. I am sure he would help you if you requested it.