End Points of 3dSolid Cylinder
CENter Object Snap will get them for you. If you want a routine to find them, entity data for 3D Solids is so inscrutable that I don't know how to get anything from that, but if you "dump" the cylinder's VLA Properties, you'll see several that look like point lists -- Centroid, MomentOfInertia, PrincipalMoments, RadiiOfGyration -- that you could experiment with. The Centroid is clear enough, though the Property needs conversion:
(vlax-safearray->list (vlax-variant-value (vla-get-Centroid (vlax-ename->vla-object YourCylinderEntityName))))
Doing the same with the PrincipalDirections Property gives a list of 9 numbers, presumably making three vectors relative to the Centroid, but you'd need to play with them, probably adding them to the Centroid with (mapcar), and/or possibly using (trans) on them, to get the results you want.
Kent Cooper, AIA 
@Anonymous wrote:
...
Postion value is set to nil 'Automation Error. Description was not provided'. I don't know if it matters, but the cylinders are created by CADworx.
Hi mracad,
as a VlaObject, the Solidtype property is Cylinder, or Extrusion?
If Cylinder, could you please attach a sample with one or two cylinders.
Henrique
Or, the maximum pipe length can be set in the CADWorx data catalog and have it cut into pieces from the start. I wouldn't recommend trying to cut pre-2013 CADWorx pipe solids (but it can be done if you are *very* careful with the XDATA), and its impossible post-2013 with the custom objects.
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If you are going to fly by the seat of your pants, expect friction burns.
"I don't know" is the beginning of knowledge, not the end.
If you are going to fly by the seat of your pants, expect friction burns.
"I don't know" is the beginning of knowledge, not the end.
@Anonymous wrote:
...
The cylinders represent a pipeline of any length and can be drawn in any direction 3-dimensionally. My goal is to find the end points of each cylinder and cut the cylinders into specific segments. Example - cut a pipe to 8' lengths with leftover at 1 end. This is why I need the endpoints of the center of the cylinders so I can calculate points along the axis of the cylinders. Note - the cylinders will always be straight segments. I don't have to worry about elbows or bends.
mracad,
I don't deal with CADWorx pipes, but if your goal is ' I need the endpoints of the center of the cylinders so I can calculate points along the axis of the cylinders.', we can use the XDATA...
This quick and dirty 'demo' will entmake a center line at selected solids
(defun c:demo (/ en i lst ss)
(if (setq ss (ssget '((0 . "3DSOLID") (-3 ("CPD1")))))
(repeat (setq i (sslength ss))
(setq ent (entget (ssname ss (setq i (1- i))) '("CPD1")))
(setq lst (vl-remove-if-not '(lambda (x) (= (car x) 1011)) (cdr (car (cdr (assoc -3 ent))))))
(entmake (list '(0 . "LINE")
'(8 . "__Demo")
(cons 10 (cdr (nth 0 lst)))
(cons 11 (cdr (nth 1 lst)))
)
)
)
)
(princ)
)
Hope this helps,
Henrique
@Anonymous wrote:
Henrique...Thanks, quick and dirty will help for now.
...
I don't want to rely on the Xdata, since it might change at anytime.
...
Still, I am wondering if there is a way to use the following values to determine the endpoints -
Centroid
PrincipalDirections
PrincipalMoments
MomentOfInertia
ProductsOfInertia
RadiiOfGyration
...
You're welcome, mracad
I also don't like to rely on Xdata on dwg's which were not produced by me.
This is not the answer you were waiting.
Determine the endpoints, using the Centroid, PrincipalDirections, ... ,RadiiOfGyration, I do not know either, but using Kailas Dhage's 'ACISdecode', probably It can be done.
Try the attached 'demo'.
Hope this helps,
Henrique
Henrique
