Joint Origin Bug, Moves and Becomes Crooked after Accepting

[therealsamchaney]

I'm once again finding more buggy behavior with joints.

I made a sketch on the surface of this component, and used a point on the sketch to make joint origin. The preview of the joint origin looks perfect, showing that the new joint origin planes are orthogonal to the face of the component (sketch plane). However, right when I click OK, the joint origin immediately moves for seemingly no reason and becomes crooked. If I make a joint using this joint origin, it similarly look perfect in the preview but then becomes crooked when I click OK. 

This is very similar to this issue I had yesterday but the workaround for that was to make a sketch and make a custom joint origin. That's what I'm doing here but now the joint origin itself is crooked even when using a sketch point rather than the auto-generated temporary joint origin.

See the screencast here. I've also attached a dummy version of the design exhibiting the issue. Edit the joint origin at the end of the timeline, and you will see that the preview is perfect, but when you click OK it just moves out of whack.

Why is this happening? This definitely just seems to be a bug. I know I can probably achieve what I'm after with some workaround but that's not the point. I'm posting this to report that Fusion is seemingly not functioning correctly so I'm posting this as a bug report so that the behavior can be fixed, not to ask for workaround solutions.

[piotr.kornafel · Accepted solution]

Hello @therealsamchaney 

I reported your issue to our developers.

When I receive any info I will let you know.

[g-andresen · Accepted solution]

Hi,

I also think that it is not correct like that.
But you can correct the directions via Reorient.

günther

[therealsamchaney]

@piotr.kornafel Great thank you very much Piotr! I'm guessing it has to do with the algorithms that try to automatically determine the orientation of the temporary joint origins. Thanks for working with us on these issues.

[piotr.kornafel]

No Problem @therealsamchaney 
We will see what our devs tell us about this 🙂

[therealsamchaney]

@g-andresen Thank you, yes manually reorienting the joint origin does stop the issue. Hopefully this will be a good clue for the dev team to use as a lead.

[g-andresen]

Hi,

the problem is caused by the design

Screencast

günther

[therealsamchaney]

@g-andresen Sure, I could have done this with a loft. I know that, and that's not the point and that's not how bug reporting works.

The problem is not "caused by the design". The problem is caused by Fusion 360 not working correctly in a particular corner case, in other words, a bug. This is clearly the case because of the fact that the preview is different from the actual resulting joint origin. At the very least, there is a bug in the preview function, and at most there is a bug in the joint origin function.

Sure, if I did it a different way that avoided that corner case, it wouldn't exhibit the bug but that doesn't mean there isn't a bug. It's like that joke where you go to the doctor and tell her it hurts when you move your arm, and she tells you to just not move your arm.

As I said in the initial post, the point of this post is not ask for workarounds, but to bring this bug to the awareness of the dev team and that has been done.