3dEntsel - Solves 3d vlax...closestpointto vs. ~2d entsel problem

Hi all. First let me echo John Uhden's sentiments in his 2002-07-17 post:
"vlax-curve-GetClosestPointTo & 3DPolylines". Though I didn't realize it
the other day, his post *exactly* describes the problem I posted:
"vlax-curve-getclosestpointto... or endpoint of?". With the exception that
mine was just a line with an elevation and I had a non-plan view current.

I am sure others have already found solutions for this, but I couldn't find
them. So here's what I came up with. Please feel free to edit, improve,
critique, etc. Feedback is welcome.

Hoping others benefit,
--
James Allen
Malicoat-Winslow Engineers, P.C.
Columbia, MO
To reply by email; ~AA~ = @ and ~DD~ = .


;;; 3dEntsel basically finds (osnap "nea"... for a given entity without
using osnap.
;;; Argument: 1. picked ename
;;; 2. pick point in UCS
;;; Returns: 1. picked ename
;;; 2. "(osnap "nea" ... in UCS
;;; Examples: 1. (setq near (nth 1 (3dEntsel (list ename pkpt))))
;;; 2. (setq esel (3dEntsel (entsel)));or nentsel or nentselp
(defun 3dEntsel (arglst / enm ob1 p1 ob2)
(setq enm (nth 0 arglst)
ob1 (vlax-ename->vla-object enm)
p1 (trans (nth 1 arglst) 1 0)
v1 (trans (getvar "viewdir") 1 0)
p1 (vlax-curve-getclosestpointtoprojection ob1 p1 v1)
ob2 (vla-addxline
(vla-get-block (vla-get-activelayout (active-document)))
(vlax-3d-point p1)
(vlax-3d-point (mapcar '+ p1 v1))
)
p1 (vla-intersectwith ob1 ob2 acExtendNone)
p1 (vlax-safearray->list (vlax-variant-value p1))
p1 (trans p1 0 1)
)
(vla-delete ob2)
(subst p1 (nth 1 arglst) arglst)
)

 

Thanks, James! I'm very interested in playing with this. "viewdir" may be the
key. It was probably Tony T. who advised using
(vlax-curve-getclosestpointtoprojection ...), but I haven't had the time to
figure out the projection part. Sadly, I have almost no play time these days,
but don't you think it's really neat how cohesive this place can be?

Joe... are you paying attention?

 

Yes, John.

Though I haven't had a chance to dig into James' post.

Joe Burke

 

" Sadly, I have almost no play time these days,
but don't you think it's really neat how cohesive this place can be?"

Absolutely. I know what you mean about play time...

James

 

In case anyone is using this, a recent post by Juerg called my attention to a couple of things.

First, the whole xline business was totally pointless. Apparently I missed the part in the help file about closestpointtoprojection that says it projects the point *back onto the curve*. LOL

Also, it hadn't occured to me that it won't work on all entities, e.g. regions. In other words, it's not quite the general solution I thought it was.

So here's a cleaner version.

James

;;; 3dEntsel basically finds (osnap "nea"... for a given entity without
;;; using osnap, provided the object is a valid curve for vlax-curve functions.
;;;
;;; Argument List: 1. picked ename
;;; 2. pick point in UCS
;;; Return List: 1. picked ename
;;; 2. "(osnap "nea" ... in UCS
;;; Examples: 1. (setq near (nth 1 (3dEntsel (list ename pkpt))))
;;; 2. (setq esel (3dEntsel (entsel)));or nentsel or nentselp
;;;
(defun 3dEntsel (arglst / obj p1 v1)
(setq obj (vlax-ename->vla-object (nth 0 arglst))
p1 (trans (nth 1 arglst) 1 0);pick ucs->wcs
v1 (trans (getvar "viewdir") 1 0);view ucs->wcs
p1 (vlax-curve-getclosestpointtoprojection obj p1 v1)
p1 (trans p1 0 1);nea wcs->ucs
)
(subst p1 (nth 1 arglst) arglst)
)