topic Re: Bug in Sweep -> Twist Angle in Fusion Design, Validate & Document Forum

Bug in Sweep -> Twist Angle

Anonymous — Sat, 28 Dec 2019 15:22:01 GMT

Sweep Twist Angle is not working for my particular sketch while it works fine with a simple square. This YouTube video shows the issue.

Sweep is Broken in Fusion 360

Re: Bug in Sweep -> Twist Angle

g-andresen — Sat, 28 Dec 2019 15:33:53 GMT

Hi,

Please share your design.

I´ve tested it, works fine.

günther

Re: Bug in Sweep -> Twist Angle

Anonymous — Sat, 28 Dec 2019 15:48:45 GMT

Here's a link to the project.

https://a360.co/2F4umMA

Re: Bug in Sweep -> Twist Angle

TheCADWhisperer — Sat, 28 Dec 2019 16:04:03 GMT

@Anonymous wrote:
Here's a link to the project.

I am pretty sure I would not have modeled in this way.

Are you attempting to follow some tutorial? If so, what is the link to the reference?

Can you explain your Design Intent?

(For example, are you attempting to model involute toothform gears? If so, what standard, what specs?)

Re: Bug in Sweep -> Twist Angle

Anonymous — Sat, 28 Dec 2019 16:09:12 GMT

I'm just trying to learn Fusion and encountered a bug. I thought they'd like to fix it.

I should be able to model my object any way I want, shouldn't I?

It should just, "work!"

I searched Google for how to report bugs in Fusion 360, and here I am.

https://www.autodesk.com/products/fusion-360/blog/how-to-best-report-issues-and-get-help/

I'm on a MacBook Pro Retina, 15-inch, Late 2013 using Fusion 360 2.0.7046

Re: Bug in Sweep -> Twist Angle

Anonymous — Sat, 28 Dec 2019 16:23:49 GMT

It looks like I may have posted to the wrong forum.

I should have posted to: Fusion 360 Support

https://forums.autodesk.com/t5/fusion-360-support/bd-p/962

Re: Bug in Sweep -> Twist Angle

HughesTooling — Sat, 28 Dec 2019 16:39:35 GMT

@Anonymous wrote:

I'm just trying to learn Fusion and encountered a bug. I thought they'd like to fix it.

I should be able to model my object any way I want, shouldn't I?

It should just, "work!"

Maybe, it could be your input profile is too complex and Fusion can't create the twisted version. If this is the problem it should fail with a warning so still a problem\bug. The preview model is low quality, when you click OK Fusion builds the high quality body and is failing.

You can leave the post in this forum and log a bug so don't worry about that too much.

~~This is not going to get fixed without your model, can you export as an f3d and attach?~~ Edit just noticed the link in post#3.

Thanks Mark

Re: Bug in Sweep -> Twist Angle

Anonymous — Sat, 28 Dec 2019 16:43:25 GMT

What I find strange though is that it shows the twisted body fine before I click, "OK" on the SWEEP dialog box. Then the instant I click, "OK" it reverts to straight. I haven't tried exporting the body to see if it's actually twisted and just displaying incorrectly.

And besides, how could it possibly be, "too complex". Either it's possible, or impossible. Too complex might mean that it takes too long to calculate. In that cause it should give me the option to abort, or wait. If I want to create something that takes hours to calculate, Fusion should allow me to do that. The computer doesn't care how long or how hard I try to make it work.

Anyway, it seems this particular sketch has hit some sort of corner case in Fusion that the developers might be interested in taking a look at.

Re: Bug in Sweep -> Twist Angle

HughesTooling — Sat, 28 Dec 2019 17:00:42 GMT

I downloaded the file and recreated the form with a spline and it works fine. All your little short sections are causing the problem.

@Anonymous wrote:

What I find strange though is that it shows the twisted body fine before I click, "OK" on the SWEEP dialog box. Then the instant I click, "OK" it reverts to straight. I haven't tried exporting the body to see if it's actually twisted and just displaying incorrectly.

As I said above, the preview is a low quality model, probably not stitched and out of tolerance. It should just fail but will then just give a generic error that will be no help.

If you give Fusion low quality inputs like this you will get fails for fillets, sweeps ect. Try and use clean profile curves with good tangency and you'll get fewer problems.

Here's what I get with a spline, note fewer surfaces and a nice clean model. I'm not to happy with the sketch as I needed to lock some geometry as you hadn't constrained all the curves. Up to you if you want to fix the sketch and do it properly.

You can see the single spline in the image below.

I've attached the f3d file. The edit of the sketch broke a lot of features in the timeline you'll need to fix.

Mark

Re: Bug in Sweep -> Twist Angle

HughesTooling — Sat, 28 Dec 2019 17:08:09 GMT

@jeff_strater What do you think on this one? Should the sweep just fail with an error or is there a bug in sweep?

Thanks Mark

Re: Bug in Sweep -> Twist Angle

g-andresen — Sat, 28 Dec 2019 17:29:43 GMT

Hi,

I agree with @HughesTooling .

Make a clean sketch and you achieve what you hope for.
I made a quick sketch and made sure that the angles and transitions were correct.
This is what the sweep looks like.

günther

Re: Bug in Sweep -> Twist Angle

Anonymous — Sat, 28 Dec 2019 18:26:47 GMT

You're saying this is too complicated for Fusion because things aren't tangent?

https://a360.co/2MBAPmy

THERE IS A BUG IN FUSION THAT SHOULD BE FIXED!

Nothing needs to be tangent, nor does anything need to be simple.

Re: Bug in Sweep -> Twist Angle

g-andresen — Sat, 28 Dec 2019 18:44:30 GMT

Hi,

1. Why are you posting this topic twice?
2. Where did I make this statement?

@Anonymous wrote:
You're saying this is too complicated for Fusion because things aren't tangent?

günther

Re: Bug in Sweep -> Twist Angle

Anonymous — Sat, 28 Dec 2019 19:14:23 GMT

@HughesTooling said, "Maybe, it could be your input profile is too complex and Fusion can't create the twisted version."

Then you said, "I agree with @HughesTooling."

I assumed you meant that my sketch was too complicated. If that's not what you meant, then what did you mean?

I suppose I should have clicked reply on @HughesTooling's comment, but yours was the last one at the time so I just clicked it.

But, you also said, "Make a clean sketch and you achieve what you hope for."

If, "clean sketch" doesn't mean a simple sketch, what does it mean?

Is this one clean? It seems to work.

https://a360.co/2ssWyWY

I posted again in the other forum because that's where the following article said I was supposed to report bugs. I wasn't looking for help. I was looking to report a bug to the Fusion 360 software developers so they could fix it. Their software is broken and should be fixed.

https://www.autodesk.com/products/fusion-360/blog/how-to-best-report-issues-and-get-help/

Re: Bug in Sweep -> Twist Angle

laughingcreek — Sat, 28 Dec 2019 20:04:08 GMT

There are indeed a few odd things going on here.

-Any time a feature fails with out giving some type of indication that it failed, I would consider that a bug.

-interestingly, the circle profile in the center seems to be causing this to fail. if you add that profile to the sweep profile, your original sketch works. what's really weird is it also works if the center "hole" is a square profile instead. This odd behavior seems buggy also.

so while your sketch makes my teeth hurt, it's not the actual cause of this particular issue.

@jeff_strater -what do you make of the 2 possible sweep bugs?

Re: Bug in Sweep -> Twist Angle

g-andresen — Sat, 28 Dec 2019 21:14:16 GMT

Hi,

I can confirm it, the inner circle is the cause.

Regardless of the outer profile, a twist will result in an error.

Günther

Re: Bug in Sweep -> Twist Angle

Anonymous — Sat, 28 Dec 2019 21:29:15 GMT

Good catch!

So now I made a video where I attempt to create the sweep with a 45 degree twist, and it fails. Then AFTER creating the sweep I edit the sketch to remove the hole, and then when I click, "Finish Sketch" suddenly the body is properly twisted.

https://youtu.be/RQcsvx_VEEU

Re: Bug in Sweep -> Twist Angle

TrippyLighting — Sat, 28 Dec 2019 23:24:11 GMT

@Anonymous wrote:

I should be able to model my object any way I want, shouldn't I?

It should just, "work!"

No and no. That is an oversimplification and does not account or the complex math and algorithms required to create compound curved geometry.

Re: Bug in Sweep -> Twist Angle

davebYYPCU — Sat, 28 Dec 2019 23:52:09 GMT

I am going with,

we know Loft can’t do it, (hollow profiles) so with the same kernel,

I am not surprised a filled profile does work.

Re: Bug in Sweep -> Twist Angle

laughingcreek — Sat, 28 Dec 2019 23:58:01 GMT

I was thinking it was similar to the loft issue also. but it works with other shaped holes, like a square or closed spline. just seems to have a problem with a centered circle. doesn't have a problem with an off center circle either.