I know about the Flatten command and that's better than nothing, but has Autocad ever figured out how to explode an ellipse into the basic 4 arc segments that they are made of instead of exploding to a spline? I know you can get crazy with ellipses, but they are a pain to work with - especially with editing. I just had to lay out seating in a stadium setting with an elliptical plan - in 3D.
To get the most exact trace of an ellipse that I can use (usually for arraying/trimming commands), I've deivided the ellipse segment using nodes and then tracing using PLINE with the Second Point command. It's accurate enough to edit and modify, but it creates LOTS of snap points (END and MID). When someone else has to work on the file, they get lazy and if they need to recreate or modify the ellipse segment, they shortcut the trace and it just gets progressively worse.
has Autocad ever figured out how to explode an ellipse into the basic 4
arc segments that they are made of ...
Ellipses are not made up of four basic arc segments. I (and
you) apparently learned how to approximate an ellipse on the boards
with a couple of constructed tangential arcs, but an ellipse's
curvature varies continuously, whereas that of an arc is fixed.
Entirely different animal down at the nano level.
As Phillip suggested, the quickest way to get a polyline of arc
segments is to set PELLIPSE = 1, and just trace the ellipse osnapping
to QUAdrant, which picks up the end points of the major and minor axes.
However, accuracy suffers: on a 100' long x 50' wide ellipse, the
polyline version varied from the true ellipse by up to 1.25". If your
anchor bolts locations depended on this, there might be trouble.
For more accuracy, I offset the ellipse a known distance, thus creating
a spline, and then offset the spline back the same distance. This gives
me a variance of only 0.01" or so. I then used ToolPac's Convert >
Splines > To Polylines function to convert the spline to a polyline
with arc segments every 24" inches, and the resulting polyline differed
from the original true ellipse by no more than 0.0005". Pretty amazing.
As someone wrote in another context, whatever you want, you can have it
good or fast or cheap -- pick any two.
I like the Pellipse setting. It's better than nothing.
Where can I get the ToolPac's Convert software? I'd like to give it a try...
My office does a lot of masterplanning, so a lot of it gets fasttracked.
I had to whip out some manuals on how to build them by hand and build it that way in 2009 so I could break it down to editable arcs.