HELP ON MAKING A SPLINE OUT OF A POINT LIST

I am trying to make a program that will automatically draw gears based on
basic parameters fed to it and I've come across a problem. Now that I
have a point list, how can I make a spline out of it. What I'm doing now
is very convoluted, I am setting up a selection set and a loop that will
draw a segment of the line for each loop and add it to that selection set
After that I use the pedit command to join the line segments and convert
them into a spline.

Also has anybody had problems with trying to use trim through Autolisp,
sometimes the trim works and sometimes it doesn't (check that out for
yourself) Even though the point I feed it resides on a line that I want
to trim nothing happens.

Thank You

This is a bit of code from the lisp file




;========================================
DRAWING THE CURVE

(setq curv (ssadd)) ; CREATE A CURVE HOLDING SELECTION SET
(setq index 0)
(repeat (length endpoints) ; WILL MAKE A WHOLE BUNCH OF LINE
SEGMENTS, AND ADD EACH OF THEM TO THE CURV SELECTION SET
(command ".line"
(nth index endpoints) ; GET THE CURRENT ENDPOINT AS THE
START OF THE LINE
(nth (1+ index) endpoints); GET THE NEXT ENDPOINT AS THE EP OF
THE LINE
""
)
(ssadd (entlast) curv) ; ADD THE LAST CREATED LINE TO THE
SELECTION SET
(setq index (1+ index))
)



(cond
(
(> bc rd) ; IF THE BASE CIRCLE IS LESS THAN THE
ROOT DIAMETER
(command ".line"
(last endpoints) ; START FROM THE END OF THE INVOLUTE
(polar center 0) (/ rd 2.0))
; AND TO THE ROOT DIAMETER
""
)
(ssadd (entlast) curv) ; ADD THE LAST ENTITY CREATED TO THE
CURV SS
)
)
(command ".pedit" "m" curv "" "y" "j" "" "s" "")
; CONVERT THE LINES GRABBED IN THE SELECTION
SET INTO A SPLINE USING THE POLYLINE EDIT COMMAND

(COMMAND ".CIRCLE" center "d" rd) ; CREATE THE ROOT DIAMETER TO TRIM
THE CURVE TO



(command ".trim" ; TRIM THE INVOLUTE CURVE UP THE ROOT
DIAMETER
(polar center 13.45) (/ rd 2.0))
""
(last endpoints)
""
)

 

by the way sorry for the caps heading didn't notice it until now.

 

do a google search for autogear.lsp & save your time for better things