Draft angle flips

[l_wcrenshaw]

I'm running into inconsistent draft angle problems with a model of mine.  I have a component and mating component that connect via a dovetail.  Part A's drafted face is drafted -20° in and part B's drafted face is drafted 20° out.  Part A likes to switch up the angle so that -20° out is now represented by being drafted in, but editing the command says -20°.  I edit the part, fix the draft from -20° to 20° so it is drafted in the correct direction.  As I continue work on the design, the draft changes again.  And again.  I just caught the last error before I submitted files to get prototyped.

[Phil.E]

Are the drafts created by a sketch? Or the Draft command?

If you can share the model or project it would be helpful to diagnose.

[l_wcrenshaw]

Draft command. I’m happy to share the model with you if that’s helpful, but I’m doing the work under contract (private files).

Lewis W. Crenshaw, IDSA, PMP
Infinite Mind Designs

[Phil.E]

No problem, confidentiality will be preserved.

You can export it as .f3d and email to me: phil dot eichmiller at autodesk dot com.

Thanks!

[Phil.E]

Thanks for the model. I'll have to analyze it next week when I have more time. Sounds like you caught it in time, please let us know if you are blocked in any way.

In the mean time, if you can think of any step that can reproduce it quickly, such as editing a particular feature or sketch, it will be extremely helpful.

[Anonymous]

I'm having the same issue with flipping angles 20, -20 degree.

I use parameters to dynamically change my part. Every time I change a parameter the angle flips from outward 20 deg to -20 deg and creating an undercut.

Is there any solution? I can send you the file if you need it?

[Phil.E]

I'll send you an email.

Thanks,

[Anonymous]

I'm also having the exact same issue (sorry, just created another post on that because I didn't spot this one here).

Any help?

Greetings,

Roland

[Phil.E]

We are investigating the most recent example as a bug. The model itself had many parametric problems (red and yellow warnings in the browser) that may contribute to this problem, which is why it seems surprising. Basically the previous poster found a new way to make this happen and there may not be a workaround other than to model the part differently.

If you can please post the model, if not let me know you can email it to me.

Thanks,

[Anonymous]

Phil,

I have simplified my model to 28 construction steps, and I'm 100% able to reproduce the bug with this model.

Unfortunately I can't post the model publicly. Can you give me your e-mail address, I'll send you the .f3d file right away (it seems that the 'private message' feature cannot handle attachments?).

Greetings,

Roland

[Anonymous]

Folks,

To share this with the community, I have simplified the model to an extent that allows me to post it here.

To whoever is interested in reproducing the bug:

Please import the attached model, then go to the named view "draft-bug". Then select Modify / Compute All (funny side effect for me: Ctrl+B does not work here) and see the draft angle on the draft flip. By continously pressing Ctrl+B, you can make it flip back and forth. It doesn't flip every time, but seems to be some 50% chance.

Greetings,

Roland

[Anonymous]

... and yes, please don't comment "you can construct that differently" - yes the construction is awkward, but that's because I simplified a much, much more complicated model.

[Phil.E]

Thanks for the file, I've added it as another case for this problem.

Regards,