Revolute joint reference does not stay in place

[Le_Bear]

I just made a Screencast to show the problem. I am far from being an expert, but I can't see what I could be doing wrong, so could this be a bug?

Willing to learn, so if I am doing anything improperly, please let me know.

Thanks,

Bernard

[James.Youmatz]

Hi @Le_Bear,

Thanks for sharing. I do agree - something seems off with this joint origin. If I had to guess, somehow that component has lost its reference in space. I'd be curious to see why that is. I did notice that this was a copy/pasted instance and I do wonder if that is coming into play.

Can you share the file with me so I can test around?

Thanks,

[TrippyLighting]

This is a bug with as-built joints and it has been reported as FUS-33516

See this thread.

If you are interested in how to get joints to work and how to link the motion of the two gears, then please share your design by exporting it as a .f3d file.

Avoid contact sets!

[Le_Bear]

Thanks for you answer. Yes, I'll share the file. I worked around the problem by making a revolute join, NOT a "as built-in revolute join. But contact set is not working.....

[Le_Bear]

here is the f3D file attached. I worked around the problem by making the 2nd join NOT "built in". I made a "section set", which does nothing, or so it seems. Would love to learn how to link both gears motion.

Thanks for your help.

Bernard

[TrippyLighting]

While I am working on a screencast, you should read up on Fusion 360's R.U.L.E #1. It's the 2nd tip in that link collection.

[Le_Bear]

Thanks! I KNOW that rule, but obviously, for such a "simple" test, forgot about it! 

[James.Youmatz]

Hi @Le_Bear,

@TrippyLighting - great find! I wasn't even fully aware of that one. Thanks for posting 🙂

Regarding the motion of the gears, I believe you are looking for Motion Link which is under the Assemble menu. What you can do is define a relationship between the two revolute joints and specify how much one revolves with respect to the other. These appear to be the same gear, so the ratio should be 1:1. Check out my screencast below. Don't forgot to ground the components though so you can mimic the motion!

[Le_Bear]

Thank you, VERY helpfull

Regards,

Bernard