Topic: 3Doffset and 3Dpoly joint ??

[Andrea]

does anyone know if thers is any command to....

1) Joint 3Dpoly with line polyline or 3Dpoly ?

2) Offset with 3d point ??

thanks.

[Swift]

1. Not by default but can be written

2. that is a tricky question, yes, it is possible, yes, in a way it is easy but in another it is extremely difficult. It has to do with the fact that each segment of a 3d polyline has the ability to fall in a different plane. Think of a lwpoly it always has the same elevation thoughout its length so the segments are offset only in the x-yplane and the same z is maintained in the offset entity. To offset a unconstrained 3dpolyline (any 3dpolyline that I can draw) would be a feat of linear algebra and may or not be possible, depending on what you are wanting to do. HOWEVER, if all you want to do is move the 3dpolyline in the x-y plane and maintain the same z for each vertex then that is fairly easy.

 I need more information.

[Andrea]

oh...

Ok....so let'S write a little routine...

I have compared both...LWPOLYLINE and POLYLINE
there is the result..

PLINE
((-1 . <Nom d'entité: 7ef5bfa8>) (0 . "LWPOLYLINE") (330 .
<Nom d'entité: 7ef5bcf8>) (5 . "F5") (100 . "AcDbEntity") (67 . 0) (410 .
"Model") (8 . "0") (100 . "AcDbPolyline") (90 . 4) (70 . 0) (43 . 0.0) (38 .
0.0) (39 . 0.0) (10 129.383 122.43) (40 . 0.0) (41 . 0.0) (42 . 0.0) (10
295.489 185.299) (40 . 0.0) (41 . 0.0) (42 . 0.0) (10 368.576 129.957) (40 .
0.0) (41 . 0.0) (42 . 0.0) (10 421.73 188.398) (40 . 0.0) (41 . 0.0) (42 . 0.0)
(210 0.0 0.0 1.0))

3DPOLY
Choix de l'objet: ((-1 . <Nom d'entité: 7ef5bfb0>) (0 . "POLYLINE") (330 . <Nom
d'entité: 7ef5bcf8>) (5 . "F6") (100 . "AcDbEntity") (67 . 0) (410 . "Model")
(8 . "0") (100 . "AcDb3dPolyline") (66 . 1) (10 0.0 0.0 0.0) (70 . (40 .
0.0) (41 . 0.0) (210 0.0 0.0 1.0) (71 . 0) (72 . 0) (73 . 0) (74 . 0) (75 . 0))


Now with the 3DPOLY I can not see all the endpoints of each segment...
how can I get it ?

I would like to do this..
1) select the entity
2) filter if it'S a POLYLINE or LWPOLYLINE or LINE
2) Get all the end points and put in a list
3) delete the selected entity
4) and remake it with LWPOLYLINE with all the points in the created list.

this is the way it seem would like to do.
But if you have better idea...or better suggestion...i'll take it.

[Bob Wahr]

Now with the 3DPOLY I can not see all the endpoints of each segment...
how can I get it ?

they are exposed in VBA although I know you don't care, I would assume to lisp as well.

4) and remake it with LWPOLYLINE with all the points in the created list.

If that's what you want, assuming you don't have a lot of them, this will be a lot less headache and will get it done:

EXPLODE
<pick a 3dpolyline>
-CHANGE
P

E
0

PEDIT
L
J
P
<select other lines, polylines, lwpolylines as desired>

and you have done it.

[Andrea]

Ok Bob..

good suggestion....but do you think this is the only way ?

[Bob Wahr]

No, not the only way.  Like I said, if you have a lot of them, it might be worth writing a program.  if not, it's a pretty big hassle.  Have to figure out which way each thing is running, compare coordinates, figure out what if any fuzz factor you want to apply.  Definitely not a 30 minute program.

[Andrea]

Ok thanks...

Last question....:

What exactly the difference between 3DPOLY and simple PLINE (excluding the width) ?

[Bob Wahr]

THE SHORTEST MOST BASIC ANSWER (sry) is that polylines (light or heavy) have a consistant Z relative to the plane they are in or to put it another way, they are flat.  3dpolylines can have a different relative Z at each vertex.

[MP]

Just to add what Bob said, I believe they are also ucs agnostic even tho they have a 210 group.

[Andrea]

 :ugly:

[Bob Wahr]

Are you making fun of the fact that my left eye is smaller than my right?  See if I ever try to help you again.

[MP]

Alfred, is that you?

[Bob Wahr]

I'm Melvin the Mop Boy.

[Kerry]

It's time to test the water.

[LE]

Is there a drawing that I can run some tests?.....

Also:
There are plenty of information about geometry out there in hyper-space, look into patterns, sequences, paths, algorithms... all about analytic geometry, graphics, etc..... why are you trying to use or focus on what AutoCAD has built-in?

There are forms to follow a pattern or path.... but is not simple or easy to do.