Hollow polyline

Hi,

Is there a polyline property that can be set so it looks hollow?

I need to get an effet similar to a polyline representation when the FILL
setting is set to OFF but only on user selected polyline.

Thanks

 

not the best idea, but it works

(setq elist(entget(car(entsel"\nSelect Polyline: "))))
(entmod(subst'(210 1e-5 0 1)(assoc 210 elist)elist))

 

Check out Dotsoft.com, where Toolpac comes from. They have a routine
which replaces plines with lines along the width. Very good; recognizes
variable widths. Naturally you should buy the whole package but some
subsets are available separately and some routines are free.

rs

 

Yvan,

See a thread dated 4/28/2004 called "Looking for a Routine". I posted a demo program
there which offsets selected lines, arcs or lwplines both sides by user input
distance. Then it caps the ends and deletes the source object.

With a little more code the new objects could be joined to form a single pline.

An alternate to user input offset distance would be use the global width of an
existing pline. But that would only work with plines, and only those which have a
global width other than zero. I think the other approach is more flexible.

Joe Burke

 

Yvan, unfortunately you have stumbled on a shortcoming of autocad at this
time. You are needing on single object type (a polyline) that has both an
outline and a fill and except for mlines, this is just not possible. Mlines
are an option, but they are difficult to modify and cannot include arcs.
The only workaround I can think of:

1) Create your polyline with the width you want.
2) Create a duplicate of that polyline exactly over the top of the first
one, but make its width a tiny bit less then the original polyline.
3) Change the color of the new polyline to a color that plots white (usually
255 in your plot style table).
4) now you should see the "white" polyline as well as the original
polyline's outline behind it. This gives the effect of the hollow polyline
upon plotting.
5) Now, to be able to stretch, copy, scale, etc these two plines as a single
unit, just group them. I would prefer to use an unnamed group. Now you
polyline will act as one polyline when you do such things as grip-edits,
stretches, etc. Unfortunately, if you wanted to do any pediting, you would
have to do it separately on each polyline. Also, this hollow "polyline" is
open on the ends so you may also want to trim off a tiny portion from each
end of the "white" polyline to effectively create "caps" on each end.


That is admittedly not a perfect solution but I believe it is all we have
right now.


FWIW,
LT

 

However, mlines *can* *approximate* an arc (just add more vertices) - which
may or may not be sufficient in this case...

BTW, Terry Dotson's ToolPac contains a couple of routines to accomplish this
by: 1- converting a curved pline or spline to a polyline with straight
segments, (about as finely as one would want), and then 2- converting said
polyline to an mline.
Again, not a perfect solution, but perhaps sufficient.

hth,
David Kozina