Component Moves Randomly Right After Making Joint

[therealsamchaney]

I'm trying to make a simply assembly of a few dice. The problem is, when I try to make a joint between one component (the D10 dice) and a point in a sketch, the joint preview looks perfect, but when I click OK, the component instantly moves to a random position. I have tried Ctrl b but it doesn't help. I've tried breaking the link to the component and it doesn't help. 

Whenever I click "OK" to accept the joint, the component just jumps to a different position for seemingly no reason. I haven't done any move commands in the assembly or in the components to my knowledge.

Why is this happening and how can I fix it? I just want the joint to actually be what the preview shows me it's supposed to be.

I have tried over and over to attach my screencast to this post but of course that doesn't work either. I have tried pasting the screencast URL then clicking preview then clicking insert, and I've tried going to MY SCREENCASTS, selecting it from the drop-down and clicking insert, but neither work. Every time, I get an error message saying:

"Your post has been changed because invalid HTML was found in the message body. The invalid HTML has been removed. Please review the message and submit the message when you are satisfied."

This is pretty infuriating because this "invalid HTML" is being inserted by the screencast insert function itself. How am I supposed to insert a screencast, when the screencast is apparently "invalid HTML"? I've never been on any other forum that can break itself with its own functions like this. 

I have given up on trying to insert the screencast so here is a link to it. 

I also just recorded it using Streamlabs and attached my own screen capture file here. 

[davebYYPCU]

No file, picture or Screencast, only you would know why that’s happening.

Edit - I don’t use Screen cast any more for that very reason. Both typing at the same time I had read your first version, no offence was meant to you.

[therealsamchaney]

@davebYYPCU Yeah the screencast issue is pretty frustrating. Better edit your comment quick before the Autodesk timer runs out and you can't edit your own comment any more! 

I've just added a link to the screencast in my post and also attached a video I made using a different program.

Any help would be greatly appreciated!

[davebYYPCU]

Will need the file or a dummy version of it.  Happens too quick and small resolution here, 

Try hiding the sketch when selecting the component to move, can only presume you are not selecting a snap point on the component. Unhide to finish the process.

Might help....

[jhackney1972]

Screencasts are easy to attach if you use the "HTML" option in the tools panel.  Select the "Embed" option, at the top of your Screencast preview, choose the size you desire.  The resulting HTML code, simply copy to you clipboard.  In your post choose the HTML tool and in the resulting box, press Enter to get a blank line and paste the copied code.

[therealsamchaney]

I'd rather not upload the file because it's full of valuable IP, but I will see if I can make a dumbed down version that still exhibits the issue. I'm definitely clicking the snap point on the model because the joint preview is correct.

[therealsamchaney]

@davebYYPCU OK I made a dumbed-down version and I've uploaded it here.

If you edit the joint feature at the end of the timeline, you will see that the preview shows exactly what I want (with the face in the center of the circle with the face on the sketch plane) but when you click OK, it instantly jumps to a seemingly random position.

[jhackney1972]

The reason your component moves to an unexpected, and undesirable, location when placing a joint is because the Joint Origin on the component is not square to the surface.  This is due to the complex shape of your component.  Take a look at the Screencast where I show this issue and a solution.

[therealsamchaney]

Thanks, that's a good workaround; I will use embed next time I need to insert a screencast.

Still, Autodesk should really be putting in some serious manpower to fix their forum website as it's the main way for users to interact for all of their products, and this issue with the screencast insert functions has been going on for a long time.

[therealsamchaney]

@davebYYPCU , I did some testing and found that if make a sketch on the face with a center point, and use that as the joint snap point, the joint works just fine. However, if I use the auto-generated snap point for the joint, the issue happens every time. 

See this screenshot below:
<iframe width="640" height="650" src="https://screencast.autodesk.com/Embed/Timeline/23354945-5996-4b82-83ea-f4682385bcf3" frameborder="0" allowfullscreen webkitallowfullscreen></iframe>

So, the issue seems to be related to the auto-generated snap point. I'm guessing this has something to do with the odd shape of the face. I have tried disabling the fillet but the bug still happens. I hope Autodesk employees can fix this issue.

[therealsamchaney]

Thanks so much John, yes that's the same conclusion I came to and the same solution as well.

I guess the automatic joint origin snap point doesn't like the shape of this face for whatever reason. I think that Autodesk could probably improve the robustness and flexibility of this feature to be able to handle shapes like this. I'm not sure what algorithm it uses to find the center but I hope it isn't just the centroid because there are much more reliable methods like this one that uses recursive subdivision.

Also, if an Autodesk programmer sees this, I would recommend adding a simple check to make sure the generated joint origin is parallel to the plane of the face it's being place on. If it's not, then maybe try a different algorithm for finding the center.

Anyway thanks again, I guess I will just have to avoid using the auto-generated joint origins until that feature is made more reliable.

[davebYYPCU]

I have not seen that unaligned joint disc problem before, seems Fusion is confused by the construction of the face, and aligns the disc to align with "something" when confused.

That the Preview works but end result is inconsistent, is one to ping @jeff_strater