find intersection of 3D lines

[giskumar]

Hi all,

 

I would like to find the intersection point between below 3D Lines

Line1: (5.0,5.0,8.0) (10.0,10.0,5.0)

Line2: (5.0,5.0,4.0) (10.0,10.0,6.0)

 

Please any one let me know how can i find the intersection point(3D) between these Lines.

 

Regards,

Kumar.

[Stefan BMR]

(setq l1 (entmakex '((0 . "LINE") (10 5.0 5.0 8.0) (11 10.0 10.0 5.0)))
     l2 (entmakex '((0 . "LINE") (10 5.0 5.0 4.0) (11 10.0 10.0 6.0)))
     )

(vlax-invoke
 (vlax-ename->vla-object l1)
 'IntersectWith
 (vlax-ename->vla-object l2)
 acExtendBoth ;or acExtendNone
 )

[hmsilva]

another way:

 

(setq p1 '(5.0 5.0 8.0)
     p2 '(10.0 10.0 5.0)
     p3 '(5.0 5.0 4.0)
     p4 '(10.0 10.0 6.0)
)
(setq intpoint (inters p1 p2 p3 p4 nil))

 

Henrique

[giskumar]

Thanks for the reply.

 

I thought these functions works on 2D only, It is good to here also works on 3D lines.

[hmsilva]

You're welcome, giskumar

 

Henrique

[BIGAL]

A bit more Inters is the original or plain jane lisp intersection command and intesectwith is the newer Vl version I would go down the VL version, intersectwith has 4 options that can be included as part of the test for an intersection, inters has 1 true or false. Intesectwith can calculate an intersection even if the lines do not cross calculating the new pt.

[gS7]

Check this

And I am sure You will Learn from this Site

 

http://www.lee-mac.com/intersectionfunctions.html

Edited January 5, 2013 by gS7

[BIGAL]

This may be a little undocumented but a time saver when typing you can replace intersect mode with 0 1 2 3

[Lee Mac]

This may be a little undocumented but a time saver when typing you can replace intersect mode with 0 1 2 3

 

All enumerations will evaluate to either an integer or some other constant data type - hence the name; the protected symbol is merely used to give some meaning to an otherwise 'magic number' e.g. (eval acbylayer) = 256.

 

I strongly disagree with your suggested 'timesaver' as it will render code unreadable and completely defeats the self-documenting purpose of the enumeration symbol.