How to: crash ACAD without a message to Autodesk.

[acwtzwegers]

Please confirm the following behaviour:

- use the elipse tool to make an elipse

- use the spline tool to trace the elipse, use the 4 quadrants of the elipse as vectors

(end up with a "drop shaped" spline)

- use spline edit > fit data > tangents:

- fit, using "tangent to" to the elipse

(spline starts taking on the shape of the elipse, but not quite)

- fit, using "tangent to" to the elipse (other side)

- wait... wait some more... notice it's locked up...

- use ctrl-alt-del, task manager and end acad's processes... notice you don't send a report to autodesk.

Tested on autocad and autocad mechanical 2012, 2013 and 2014 on 3 different PCs running XP and Windows 7.

(and I just wanted to have a elipse-shaped spline)

[nestly2]

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acwtzwegers wrote:

(and I just wanted to have a elipse-shaped spline)

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 I didn't test to see if I could cause a hang/crash, but if all you need is an elipse shaped spline, Create an Elipse and use OFFSET.  Erase the elipse and OFFSET back the same distance.

[acwtzwegers]

I know, that's not the point though.

Tried to make one by tracing the elipse and the result surprized me.

[acwtzwegers]

Also works if you first make a closed spline, then an elipse - and only then use spline edit > fit data > tangents.

In that case it crashes more quickly: when fitting "tangent to" the first time.

[dmfrazier]

I can't duplicate your "crash" (AutoCAD 2013, Win7 32-bit), but it may be that I'm not "exactly" duplicating your steps.

Here I've numbered your steps:

1. use the elipse tool to make an elipse

2. use the spline tool to trace the elipse, use the 4 quadrants of the elipse as vectors

(end up with a "drop shaped" spline)

3. use spline edit > fit data > tangents:

4. fit, using "tangent to" to the elipse

(spline starts taking on the shape of the elipse, but not quite)

5. fit, using "tangent to" to the elipse (other side)

6. wait... wait some more... notice it's locked up...

7. use ctrl-alt-del, task manager and end acad's processes... notice you don't send a report to autodesk.

Maybe it doesn't matter, but, at step #1, the ellipse I created was roughly twice as wide as it was tall.

At step #2, in what order do you pick the quadrant points on the ellipse?  (Maybe it doesn't matter, but I started at 9:00, then 12:00, 3:00, 6:00, then Closed it.  There was a brief "delay" at this point before the command prompt returned.)  The resulting spline very nearly duplicated the ellipse (it was not "drop shaped").

There's some ambiguity at steps #4 & #5.  What point(s) on the ellipse should I pick after the Tan snap? With Ortho off, as I move the cursor over the ellipse, I see "Deferred Tangent" appear at the cross-hairs.  With Ortho on, "Tangent" appears.  In either case, a rubber-band line stretches from the node at 9:00. At step #4 you indicate that the spline "starts taking on the shape of the elipse", but my spline was already pretty darn close when I created it, and anywhere I pick on the ellipse actually distorts it.

At no point does AutoCAD "lock up" or "crash".

[acwtzwegers]

Thank you for trying.

Elipse shape or quadrant order doesn't seem to matter.

But I do not "Close" the spline: in your case I would have gone from 9 o'clock to 12 to 3 to 6 and back to 9 - after which I use enter to finish the command.

Then: double click the spline, pick "fit data", pick "tangents"

In my case it will then just use the first vector, no matter what. I do ctrl-right click, pick tangent, click on the elipse.
Repeating the last step next will then crash.

[dmfrazier]

Just to clarify further (in case it matters), my Spline settings are: Method=Fit   Knots=Chord.

"But I do not "Close" the spline: in your case I would have gone from 9 o'clock to 12 to 3 to 6 and back to 9 - after which I use enter to finish the command."

I think it may matter which method is used.  When I use "Close" after picking the 6:00 quadrant point, the spline consistently takes on nearly the exact shape of the ellipse.  However, if I select the 9:00 point again, followed by hitting <Enter>, a "drop-shaped" spline is created.

Following your remaining steps on the red spline, I could not get the spline to match the original ellipse, but I could not get AutoCAD to "crash", either.

Something to check: on a couple test runs, somehow a 6th vertex was introduced to the spline (I'm relatively certain I did not select a point after the 2nd 9:00 pick and before hitting <Enter>). This produced a slightly more distorted "ellipsoid", but even with those I could not duplicate your result.

[scot-65]

(setvar "REPORTERROR" 0)

[acwtzwegers]

Thanks for trying 🙂

I guess the error came from me basically misusing the spline command.

Further testing has pointed out that "polar tracking" has to do with the crash.

Switching on/off dynamic input, object snap tracking, dynamic ucs etc did not change anything - but with polar tracking on, I get the crash as described.

[acwtzwegers]

Thanks Scott, but this crash will not report with that variable on or off 😛

[acwtzwegers]

Updates: 
I get this crash with some splines closed by just putting the end at the starting point.

The elipse is not completely irrelevant though: I just drew (and made into fluid, tangent shapes) quite a few splines without hanginging using the following method. It only crashed when I traced another elipse (as described before). A circle does not give me the same effect, nor does making a spline using four "elipse quadrant" like locations without an elipse. I did get it on a drawing with just a spline though... hypothesis atm is that it is angle-related and tracking related. Some variable going to nil or 0 while it shouldn't. It's not fully consistent though. ( even though yesterday I thought it was).

With polar tracking on, object snap tracking on:
1. close the spline by going back to the start and ending the command.
2. spline edit > fit data > tangents
3. _tan to (itself)
4. _tan to (itself)... hang.