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Crash Resolution

Posted: Mon May 29, 2017 11:17 pm
by debenriver
From time to time I get crashes with RealCADD – and once it happens, it often seems to get progressively worse.

I've known for some time that arcs in particular can, for some reason, get created without a centre, that is xc = NAN and yc = NAN (perhaps Eric will know why ...). I think it is possibly when using the fillet tool but failing to get a fillet. And if you have one of these in your drawing it will likely cause a crash, to the point where trying to select anything, or draw a marquee with the select tools, will cause a crash.

The solution: easy!!

Go to Edit >> Special Select. Click the "None" button and then check the "Arcs" box (which will make it go to the "Some" button). Check the "Length object = 0 or empty string" box and hit OK. This will select all "empty" arc objects. If you have arcs with a NAN centre, or a zero length, they will show in the Edit pallet. Simply hit the delete key and they are gone!

It's so obvious when you think about it – but I've been using RC for years without realizing what that box was for ... :mrgreen:

You can repeat the process with other objects that may be "empty" (lines, rectangles etc). On a drawing that was crashing badly recently, I removed three empty arcs and I also found that I had several empty lines as well, and I removed them. It has been rock solid since. :D

I will add a paragraph about this to the Manual.

Cheers -- George

Re: Crash Resolution

Posted: Tue May 30, 2017 9:23 pm
by debenriver
I've added a new section to the "Edit >> Special select ..." area of the manual to discuss use of the "Length object = 0 or empty string" box and it's relevance to crash prevention!

Cheers -- George

Re: Crash Resolution

Posted: Wed May 31, 2017 6:31 am
by Eric Pousse
Thank you very much George !

Re: Crash Resolution

Posted: Thu Jun 01, 2017 12:23 am
by debenriver
Well it's you Eric who identified the problem to me and Tony (my colleague and another RealCADD user), when we were having troubles with a drawing for a radio controlled airplane design. For some reason Tony managed to create rather a lot of NaN arcs. It just took a while to sink in that there was a simple way to fix it!

I'm happy to report that the airplane, with parts cut from the RealCADD drawing, flew very successfully here in Rockland, Maine.

Tony mostly uses RealCADD in his work designing and building drones – but we were having a bit of fun doing a fixed-wing airplane.

Cheers -- George

Re: Crash Resolution

Posted: Thu Jun 01, 2017 5:07 am
by Mikerosen
George,
What does NaN mean? I am experiencing multiple crashes when using arcs, although Eric hasn't been able to duplicate it. He suggested I look at this thread, but I'm afraid I don't understand. Is there a setting I should make to prevent the crashes, or is your discussion only for a special circumstance?

Re: Crash Resolution

Posted: Thu Jun 01, 2017 12:01 pm
by debenriver
Hi Mike

NaN is short for Not a Number – you will see it in the Edit pallet sometimes – often when there is a problem.

If you have a drawing that crashes (to do with arcs or otherwise), with the crashing drawing open and current, go to Edit >> Special select...

– Click the "None" bullet under "Objects".
– Then check the "Arc" box (the Objects will change to "Some").
– Check the "Length object = 0 or empty string" box.
– Check the "All Objects" box (it's usually checked by default).
– Hit OK.

It will select all arcs in your drawing that are empty or have NaN data in some way.

If you do have any "empty" arcs in your drawing you should see the Edit pallet looking something like one of these:
empty.jpg
empty.jpg (12.92 KiB) Viewed 7834 times
The right-hand image shows that arc No.2 out of a total of 3 has no proper centre –– xc and yc are NaN. The left hand image shows Arc No. 1 out of 3 has no start angle, no included angle and no length. I don't know if this will cause a crash but I definitely know that an arc with NaN in its data does, and removing them fixes the problem.

You can cycle through the selected arcs using the little arrows at the top of the Edit pallet. But don't click on the drawing else you will deselect them.

To get rid of all of them in one go, all you have to do is hit the Delete key or ⌘X and they will be gone. The drawing should then be crash-free.

You can repeat the process with other objects - like Lines for example. I have found empty lines on a drawing, but I don't think they cause a crash (I don't know this for sure however!). I've found it best to cycle through each object separately rather than select several at once. I've only ever found empty arcs and lines - never any other object - but that could just be a function of how I draw.

I assume they come from a failed trim or fillet - or something like that. Drawing can often leave odd fragments of objects about that aren't part of the drawing as such, but are left over from various operations during drawing. Mostly they don't cause a problem but in RealCADD, arcs with NaN in their data do absolutely cause a problem. The process I have described "cleans up" the drawing and gets rid of them.

Hope this helps.

Cheers -- George

Re: Crash Resolution

Posted: Sat Jun 03, 2017 6:32 pm
by Mikerosen
Thanks. I'll try to spend some time understanding.

(Remember: I was a theater major!)