split spline in lowest point

[mivankovic971349]

Could somebody write me a routine which would split a spline in it's lowest point, please?

[Tharwat]

Can you explain more in details please ?

Tharwat

[mivankovic971349]

I need to split a parabola like this one (unknown start and end)
http://www.google.hr/imgres?start=24...13,s:247,i:204
into 2 pieces in it's lowest point.

I've been working all day on a somewhat mathematical solution (putting a horizontal line inside of the parabola, then putting a vertical line in the center of the horizontal one and breaking the spline (parabola) in the intersection of the vertical line and the spline).

I was hoping someone with more programming skill could help me with a more elegant solution (one which works on splines of any type)

[GHarvey]

Give this a try...

(defun c:foo ( / MAXPT MINPT OLDOSMODE PTA SPLINEOBJ VLA-SPLINEOBJ)
  (setq splineobj (car (entsel))
	vla-splineobj (vlax-ename->vla-object splineobj)
	); setq
  (vlax-invoke-method vla-splineobj 'getboundingbox 'minpt 'maxpt)
  (setq pta (vlax-curve-getclosestpointtoprojection
	      vla-splineobj
	      (list 0.0 (- (cadr (vlax-safearray->list minpt)) 10.0) 0.0)
	      (list 1.0 0.0 0.0)
	      nil
	      ); vlax-curve-getclosestpointtoprojection
	oldosmode (getvar "osmode")
	); setq
  (setvar "osmode" (boole 7 (getvar "osmode") 16384))
  (vl-cmdf "break" splineobj pta pta)
  (setvar "osmode" oldosmode)
  (princ)
  ); defun

Note that it is absolutely bare-bones, with no error handling, and assumes that there is only one "lowest" point on the curve.

[mivankovic971349]

thank you