#Some OSNAP Problem/s
7 messages in this thread
Tony,
I wondered what the '3rd man' was point wise, thanks. I may be
being stupid here, but are you saying that a change in perspective forces
LASTPOINT to nil, hence the inability to calculate PERpendicular? Also,
does ads_osnap work in the same fashion?
hsm
Hugh – Are you working in perspective views? I've not checked, but going by
the fact that pointing is not allowed in perspective views, and that object
snap is in essence, a form of pointing, then I wouldn't be surprised if (osnap)
and ads_osnap() didn't function in a perspective view.
-TonyT.
Tony,
No, DVIEW is off, the problem occurs in plane jane Acad, no
buttons, bows or frills. Just seems like if the object of the "PER" is off
screen due to zoom, then osnap fails. I've written my way around this
problem on the ads side so its no big thing, just seems a little odd is
all…
hsm
Hugh – Well okay, in that case, it's not too odd. Your original question
gave me the impression that you were referring OSNAP not working if the
"basepoint" (e.g., "LASTPOINT"), wasn't on screen, not the selection point
or the entity that you're object-snapping to.
The very same rules that apply to entity selection using the 'pickbox' also
apply to entity selection using the osnap aperture target. The point that
you give the (osnap) function is a selection point which the aperture target
is centered on. The aperture target that's centered on this point must be
on-screen in order for AutoCAD to find an object.
AutoCAD must locate the object you want to OSNAP to using screen vectors and
there aren't any screen vectors for objects or parts of objects that are off-
screen so to speak, and hence, it can't find an entity at a selection point
that is off-screen.
-TonyT.
Tony,
Ah Ha! or maybe oh! Good thing I wrote my own in that case. Thanks
for the clarification Tony, it helps a great deal. As and when…
hsm
Tony, do you really mean that the object must be "on screen" or are you
refering to its existance in the integer (redraw) database that ACAD
produces?
Steven – Yes, AutoCAD locates them by examining screen vectors, so selecting an
object by specifying a point, requires that there be screen vectors near the
point.
-TonyT.