Transform points from lwpolyline with entmod
First question: Do Polylines that you want to project in this way ever include arc segments? Those would become elliptical in projection if the source Polyline is not parallel to the plane you want to project it onto, so a Polyline could not be an accurate projection.
If the polyline only have line segment (as noticed by @Kent1Cooper), this routine should do the trick:
(defun projectOnViewPlane (pline / elst el vd)
(setq elst (entget pline)
el (cdr (assoc 38 elst))
vd (trans '(0 0 1) 2 0 T)
)
(entmod
(mapcar
(function
(lambda (x)
(cond
((= 10 (car x)) (cons 10 (trans (list (cadr x) (caddr x) el) pl vd)))
((= (car x) 38) (cons 38 0.))
((= (car x) 210) (cons 210 vd))
(T x)
)
)
)
elst
)
)
)
@carlos_m_gil_p a écrit :
Try applying it to the red polyline and it gives an error.
(setq lw (car (entsel)))(projectOnViewPlane lw)
It works as expected for me. What's the error message ?
Oops!...
My mistake (pline instead of pl).
(defun projectOnViewPlane (pl / elst el vd)
(setq elst (entget pline)
el (cdr (assoc 38 elst))
vd (trans '(0 0 1) 2 0 T)
)
(entmod
(mapcar
(function
(lambda (x)
(cond
((= 10 (car x)) (cons 10 (trans (list (cadr x) (caddr x) el) pl vd)))
((= (car x) 38) (cons 38 0.))
((= (car x) 210) (cons 210 vd))
(T x)
)
)
)
elst
)
)
)
It does work (as shown in the screencast)
@carlos_m_gil_p a écrit :
I don't know how to use the lambda function, but in the result I see that the codes 10 have 3 values (x y z) and I think they should be 2 (x y)
It does not matter if there's the Z coordinate or not in the 10 group and as you can see it's equal to 0 or (very closed to).
If you enter: (projectOnViewPlane (car (entsel))) at the command line and the command line shows the new DXF list, that means it worked.
You can replace entmod with entmake so that you'll see the source polyline and the newly created one.
The white polyline is not a rectangle (i.e. a 4 vertices closed polyline). It is a 2 vertices polyine vertices with a thickness (it could be a line a thickness), an projecting such entity will always generate a 2 vertices polyine vertices with a thickness.
This is not the routine which need to be modified, this is the input entity.
