planar spline via command

Hi all
Here is something I use to draw splines (found on the Web)

(command "_SPLINE")
(mapcar 'command ptlist) ; the ptlist must be the fitpoints then
(command "" "" "")

Works fine, but here is the question (very important, if somebody can
help)

above code draws spline from supplied list of coordinates - ptlist,
but resulting spline is non-planar, even if the list is of the form
((x1 y1) (x2 y2) ....). I desperately need a planar spline (so I can
use offset).
Can something be done to do so?

 

Roman,

sorry but i cant help, because at my AutoCAD (2004) the spline is planar and can be offset. I uses this list for testing:
(setq ptlist '((7 5) (7 3) (7 3) (8 1) (7 3) (6 5) (4 2)))

maybe you should try to add zeros for z:
(setq ptlist '((7 5 0) (7 3 0) (7 3 0) (8 1 0) (7 3 0) (6 5 0) (4 2 0)))

bob.at

 

I did try both cases - still non-planar.
It is not like I can't get a planar one in other cases, I can.
I suspect that the problem comes from running my lisp application in an orthogonal view and some consequences of UCS/WCS settings - but it is only my suspicion.

 

I have tried it in another UCS and its alos planar, even if i switch back to WCS.
sorry, no more ideas

bob.at

 

Any chance you have running OSNAP modes on, that might make the routine
latch onto locations in existing drawing entities that are not in the same
plane as your defining points? (I haven't kept the original post, so I
don't have it to look at -- this is a grab-at-straws supposition.)

Kent Cooper, AIA

orthogonal view and some consequences of UCS/WCS settings - but it is only
my suspicion.

 

That's a possibility! I'll give it a try. I understand the idea is to switch off all osnap settings?

Here is the code I'm using:

(command "_SPLINE")
(mapcar 'command ptlist) ; the ptlist must be the fitpoints then
(command "" "" "")

 

Thanks Bob
At least we a getting closer to the solution (I hope).

 

Yes, turn off or disable all running osnap settings. You could set OSMODE
to 0, but that is equivalent to OSNAP OFF, and clears all the settings.

Or go to the Command Reference in Help and look at the description of OSMODE
in the System Variables, to see how AutoCAD disables them (without clearing
them) when you pick the OSNAP button in the Status Bar (or hit F3). That
way your current combination of osnap settings will be preserved.

Or maybe easier than that, you can save the value of OSNAP before the
routine, and restore it again at the end:
(setq osnapsettings (getvar "OSMODE"))
....your routine...
(setvar "OSMODE" osnapsettings)

You could also try your routine in a drawing with nothing in it, because if
you still get a non-planar result, then the OSNAP question is moot.

Kent Cooper, AIA

 

Whoops... Forgot to add the clearing of Osnap settings to the suggestion
for saving and restoring them. Should have been:

(setq osnapsettings (getvar "OSMODE"))
(setvar "OSMODE" 0)
....your routine...
(setvar "OSMODE" osnapsettings)


Kent Cooper

...
.....

routine, and restore it again at the end:

.....

 

I've turn everything off - still no luck.
I do have some objects in the drawing when the routine runs - manipulating them is all the point. And the routine uses some osnap itself, called by "per". May be I should switch to new layer, turn all other layers off, and then draw this damn spline.