交点和
你好使用marko_ribar lisp来自：
https://forums.autodesk.com/t5/visual-lisp-autolisp-and-general/to-get-intersection-between-a-line-and-a-3dface/td-p/2745633/page/3
我制作了一个版本，在垂直线与3dface的交点处插入一个点。我有许多看起来像三角形的3dFaces。我使用lisp制作它们：
http://paulbourke.net/papers/triangulate/Triangulator.LSP
我的lisp有时能工作，有时会打印错误。
谢谢你的帮助
;_ilt= intersection line and 3dface
;by marko_ribar
;link: https://forums.autodesk.com/t5/visual-lisp-autolisp-and-general/to-get-intersection-between-a-line-and-a-3dface/td-p/2745633/page/3
;
(defun _ilt ( p1 p2 t1 t2 t3 / v^v unit Coplanar-p ptinsidetriangle-p ptontriangle-p ptonline-p _ilp nor o )
(defun v^v ( u v )
(list
(- (* (cadr u) (caddr v)) (* (cadr v) (caddr u)))
(- (* (carv) (caddr u)) (* (caru) (caddr v)))
(- (* (caru) (cadrv)) (* (carv) (cadru)))
)
)
(defun unit ( v )
(mapcar '(lambda ( x ) (/ x (distance '(0.0 0.0 0.0) v))) v)
)
(defun Coplanar-p ( p1 p2 p3 p4 )
(
(lambda ( n1 n2 )
(equal (v^v n1 n2) '(0.0 0.0 0.0) 1e-
)
(v^v (mapcar '- p1 p2) (mapcar '- p1 p3))
(v^v (mapcar '- p1 p2) (mapcar '- p1 p4))
)
)
(defun ptinsidetriangle-p ( pt p1 p2 p3 )
(if
(and
(Coplanar-p pt p1 p2 p3)
(not
(or
(inters pt p1 p2 p3)
(inters pt p2 p1 p3)
(inters pt p3 p1 p2)
)
)
(not
(or
(> (+ (distance pt p1) (distance pt p2)) (+ (distance p3 p1) (distance p3 p2)))
(> (+ (distance pt p2) (distance pt p3)) (+ (distance p1 p2) (distance p1 p3)))
(> (+ (distance pt p3) (distance pt p1)) (+ (distance p2 p3) (distance p2 p1)))
)
)
)
T
nil
)
)
(defun ptontriangle-p ( pt p1 p2 p3 )
(if
(or
(equal (distance p1 p2) (+ (distance pt p1) (distance pt p2)) 1e-7)
(equal (distance p2 p3) (+ (distance pt p2) (distance pt p3)) 1e-7)
(equal (distance p1 p3) (+ (distance pt p1) (distance pt p3)) 1e-7)
)
T
nil
)
)
(defun ptonline-p ( pt p1 p2 )
(equal (distance p1 p2) (+ (distance pt p1) (distance pt p2)) 1e-7)
)
(defun _ilp ( p1 p2 o nor / p1p p2p op tp pp p )
(if (not (equal (v^v nor (unit (mapcar '- p2 p1))) '(0.0 0.0 0.0) 1e-7))
(progn
(setq p1p (trans p1 0 (v^v nor (unit (mapcar '- p2 p1))))
p2p (trans p2 0 (v^v nor (unit (mapcar '- p2 p1))))
op(trans o 0 (v^v nor (unit (mapcar '- p2 p1))))
op(list (car op) (cadr op) (caddr p1p))
tp(polar op (+ (* 0.5 pi) (angle '(0.0 0.0 0.0) (trans nor 0 (v^v nor (unit (mapcar '- p2 p1)))))) 1.0)
)
(if (inters p1p p2p op tp nil)
(progn
(setq p (trans (inters p1p p2p op tp nil) (v^v nor (unit (mapcar '- p2 p1))) 0))
p
)
nil
)
)
(progn
(setq pp (list (car (trans p1 0 nor)) (cadr (trans p1 0 nor)) (caddr (trans o 0 nor))))
(setq p (trans pp nor 0))
p
)
)
)
(setq nor (unit (v^v (mapcar '- t3 t1) (mapcar '- t2 t1))))
(setq o t1)
(if (_ilp p1 p2 o nor)
(if
(and
(or
(ptinsidetriangle-p (_ilp p1 p2 o nor) t1 t2 t3)
(ptontriangle-p (_ilp p1 p2 o nor) t1 t2 t3)
)
(ptonline-p (_ilp p1 p2 o nor) p1 p2)
)
(_ilp p1 p2 o nor)
nil
)
nil
)
)
;;
;;BECAUSE THE 3DFACE HAVE 4 VERTICES (2 the same) WE HAVE TO REMOVE DUPLICATED COMPONENTS
;;
;; Unique-Lee Mac
;; Returns a list with duplicate elements removed.
(defun remove_doubles(lst /)
(vl-load-com)
(if lst
(cons (car lst) (remove_doubles (vl-remove (car lst) lst)))))
;;
;;Main program
(defun c:bum ()
(print "pick 3dFace")
(setq ssSelections (ssget))
(setq Point (getpoint "\nPICK A POINT"))
(setq Point2 (list (nth 0 Point) ; Point i Point2 = line of 500 length (Line that crosses 3dface)
(nth 1 Point)
500))
(repeat (setq intCount (sslength ssSelections))
(setq intCount (1- intCount)
entSelection (ssname ssSelections intCount)
lstEntity (entget entSelection))
;3DFACE vertices
(setq P10 (list (nth 1 (assoc 10 lstEntity))
(nth 2 (assoc 10 lstEntity))
(nth 3 (assoc 10 lstEntity)) )
P11 (list (nth 1 (assoc 11 lstEntity))
(nth 2 (assoc 11 lstEntity))
(nth 3 (assoc 11 lstEntity)) )
P12 (list (nth 1 (assoc 12 lstEntity))
(nth 2 (assoc 12 lstEntity))
(nth 3 (assoc 12 lstEntity)) )
P13 (list (nth 1 (assoc 13 lstEntity))
(nth 2 (assoc 13 lstEntity))
(nth 3 (assoc 13 lstEntity)) ))
;List of vertices with one (duplicate) deleted
(setq ListVtx (remove_doubles (list P10 P11 P12 P13) ))
;Others 3 vertices
(setq P100 (nth 0 ListVtx)
P101 (nth 1 ListVtx)
P102 (nth 2 ListVtx))
;Making 3dPoint
(entmake (list '(0 . "POINT") (cons 10 (_ilt Point Point2 P100 P101 P102)) ))
);end repeat
);end bum
我以前很幸运做过这种测试：
; 3 Points To 210 Extrusion Direction (LeeMac)
(defun normal ( p1 p2 p3 )
(defun vxs ( v s )
(mapcar '(lambda ( n ) (* n s)) v))
(defun nrm ( v )
(sqrt (apply '+ (mapcar '(lambda ( n ) (* n n)) v))))
(defun one ( v )
(vxs v (/ 1.0 (nrm v))))
(defun vcv ( u v )
(list
(- (* (cadr u) (caddr v)) (* (cadr v) (caddr u)))
(- (* (carv) (caddr u)) (* (caru) (caddr v)))
(- (* (caru) (cadrv)) (* (carv) (cadru)))))
(one (vcv (mapcar '- p3 p2) (mapcar '- p3 p1))))
(defun c:test (/ p10 p11 f10 f11 f12 ucs pt1 pt2)
(setq ld (entget line_ename)
p10 (cdr (assoc 10 ld))
p11 (cdr (assoc 11 ld)))
(setq fd (entget face_ename)
p10 (cdr (assoc 10 ld))
p11 (cdr (assoc 11 ld))
p12 (cdr (assoc 12 ld)))
(setq ucs (normal f10 f11 f12)
pt1 (trans p10 0 ucs)
pt2 (trans p11 0 ucs))
(if (setq ip
(inters pt1 pt2
(list (car pt1) (cadr pt1) 0)
(list (car pt2) (cadr pt2) 0) nil))
(prin1 ip)
(alert "Line Does Not Intersect This Plane"))
(prin1))
假设3dface 12和13相等
如果该线与ucs平面平行，则它将永远不会相交（您的错误可能来自此）
基本上找到了转换为3个面点ucs的2条线的（inters）
通常我会将ip转换为WCS。
HTH-David 谢谢你的回答。
我认为在我的代码中，有时函数_ilt print nil，所以它不能给出一个点。 我想我会分享我写的这段代码，以确定任何直线（由2个点定义）与三维面定义的平面的交点。它会检查直线是否与平面平行，但不会检查点是否在面边界内。
(defun c:FaceIntr (/)
;finds the point of intersection of a line defined by two points and a plane defined by
;a 3DFace
;L. Minardi3/28/2017
(princ "\nPlease select 3DFACE and press ENTER.")
(setq ss (ssget) ; get data for 3Dface
en (ssname ss 0)
edata (entget en)
)
(setq p1 (getpoint "\nLine Start:"); get two line points
p2 (getpoint p1 "\nLine End")
p1p2 (mapcar '- p2 p1) ; vector from p1 to p2
)
(setq fp1 (cdr (assoc 10 edata)) ;three corners of the 3DFACE
fp2 (cdr (assoc 11 edata))
fp3 (cdr (assoc 12 edata))
)
(setq N (cross fp12 fp23)) ; normal to face
(setq fp1p1 (mapcar '- p1 fp1) ; vector from face to line
p1p2(mapcar '- p2 p1) ; vector paralled to line
)
; determine if line is parallel to plane
(setq Nxp1p2 (cross N p1p2)) ; N cross p1p2
(setq Ntp1p2 (* (distance '(0 0 0) N) (distance '(0 0 0) p1p2)))
; magnitude N times magnitude p1p2
(setq
sinang (/ (distance '(0 0 0) Nxp1p2) Ntp1p2); sine angle between normal and line p1p2
)
(if (equal sinang 1.0 0.0001)
(princ "\nNo intersection, the line is parallel to the face.")
(progn
(setq tk (- (/ (dot N fp1p1) (dot N p1p2))) ; value of parameter t at intersection
) ; intersection point of line and face using parametric definition of a line
(setq PInt (mapcar '+
p1
(mapcar '* (mapcar '- p2 p1) (list tk tk tk))
)
)
(command "point" Pint)
(command "line" p2 Pint "")
(setq s (distance p2 Pint))
(princ "\n The intersection point is located at: ")
(princ Pint)
(princ
"\nThe distance from line end point to the intersection is: "
)
(princ s)
)
) ; end if
(princ)
) ;end Face-Intr
;;; Compute the cross product of 2 vectors
(defun cross (a b / crs)
(setq crs (list
(- (* (nth 1 a) (nth 2 b))
(* (nth 1 b) (nth 2 a))
)
(- (* (nth 0 b) (nth 2 a))
(* (nth 0 a) (nth 2 b))
)
(- (* (nth 0 a) (nth 1 b))
(* (nth 0 b) (nth 1 a))
)
) ;end list
) ;end setq c
) ;end cross
;;; Compute the dot product of 2 vectors a and b
(defun dot (a b / dd)
(setq dd (mapcar '* a b))
(setq dd (+ (nth 0 dd) (nth 1 dd) (nth 2 dd)))
) ;end of dot
页:
[1]