find intersections

I am building a routine to take a closed polyline an find any occurance of intersections along it. Does anyone have a good method to do this?

 

I use something like this:

(setq endpt (vlax-curve-getendpoint obj))
(setq begpt (vlax-curve-getstartpoint obj))
(setq slen (/ len nseg)); segment length
(setq di slen pb begpt)
(repeat nseg
(setq pa (vlax-curve-getpointatdist obj di))
(setq cc 0)
(if hs
(progn
(setq nh (sslength hs)); # house lines
(repeat nh
(setq ename (ssname hs cc))
(setq lent (entget ename))
(setq p1 (cdr (assoc 10 lent))); end point1
(setq p2 (cdr (assoc 11 lent))); end point2
(setq cp (polar p1 (angle p1 p2) (/ (distance p1 p2) 2.0)))
(setq pnt nil)
(setq pnt (inters p1 p2 pa pb T))
(if pnt
(progn
...... do whatever

Bob

 

I think i need to clarify what I am looking for.
I have a closed polyline...
I need to find any other entities in the drawing that intersect it and then store the intersection location.

 

This line does the checking for intersecting objects:
(setq pnt (inters p1 p2 pa pb T))
where, pa and pb are 'endpoints' of some line that
(may) intersect. If the line (does) intersect, the intersection
point is returned in variable pnt.

The portion of the routine posted goes through a closed
polyline, and examines all 'line' objects on the drawing, and
if they intersect, returns that point...

Bob

 

Hi 'hulioman'

Visit my homepage -> Free Stuff and search for 'VxGetInters' and
'VxGetBlockInters'.

Cheers