Manipulating joints while keeping components static

[Anonymous]

I'm currently in the 'raw beginner' phase of learning Fusion 360. Something I'm struggling with is how to create joints. I'm working on a tutorial project wherein I'm making a simple folding TV tray. The instructor has been pretty good but I'm a bit stumped by how to make joints work. 

My issue is that the Rotational joint command keeps taking my two components and jamming them into the same space. I am attempting to create a simple hinge around what would be a screw-hole that connects the two legs. How do I anchor the components in place so that the Joint command doesn't 'pull' them into the same space and disrupt all my other parameters?

[davebYYPCU]

Will need some more details, one component has to be grounded, 

before clicking ok, 

does the joint preview show the correct / desired movement,

if so use the move triad handles to set up the correct alignment,

Then you should be able to click ok, with confidence, 

None of the above,

File > Export, and save to the hard drive, add to another post here, there is an attachment window / box lower in this page.

[TrippyLighting]

Perhaps you can also provide a link to that tutorial.

I've seen a number of tutorials all made in good spirit that should never have been made!

[Anonymous]

Yes, the joint shows the correct movement and it rotates properly. I grounded the main component I am building off of, so that's working as desired. 

What I'm trying to do is attach the rounded corner of the upper legs to the supports on the underside of the tray top. It'll just be a simple pass-through bolt hinge. I just want to figure out if there's a way to do that with the Join command while maintaining that offset that's in place. Every time I join the two holes together, it forces the two leg struts to occupy the same physical space. I can fix that by hand, but I'd like to know if there's an actual way to do this properly from the get-go.

[Anonymous]

It's on Udemy.com, unfortunately the course is paywalled.

[TrippyLighting]

I bet that tutorial did not instruct you to not fix the obvious red highlighted mistakes in your design.

Start with fixing that that while I continue to look at your design.

[Anonymous]

Obvious mistakes? I'm sorry, I am extremely new here-- this is literally the third thing I've ever built in Fusion. What's the problem?

[Anonymous]

So from what I'm seeing here, there's no way to keep those components from jumping around while assembling the joint? I just have to measure out my offsets ahead of time and then reproduce them after I set the joint up?

[chrisplyler]

OR... just use an As-Built Joint type, which as I explained, doesn't make one of the components move at all.

[davebYYPCU]

@chrisplyler You needed a Pin Slot when the inside frame was a rigid group., cause the pin needed to rotate with the legs.

You did not give qualification that as it is from a tutorial, there was not much commentary as to why you were deleting the stuff you did, for a newby looking on he would be left wondering about your refined method over what was / mighta been taught.

Made sense by the time you had it cleaned up to me, but, you deleted model features and did not replace them.  That's not good.

@Anonymous Chris has explained all the Joint system, yes offsetting is known before hand, but the one thing I am concerned with is your question about losing parameters.  Were you asking about User Parameters, or more likely the Component positions / locations?

[Anonymous]

I meant more in terms of how the legs are placed in relationship to one another, sorry. So if the 'support' component is grounded in place, then I want .1" to the next leg, then another .1" to the next leg. But I didn't use any special parameters to index the legs against the supports, if that makes any sense. 

[TrippyLighting]

@Anonymous My use of the word "obvious" appears to have offended you, but that was definitely not my intention. Please accept my apologies!

The reason why you are having problems with this assembly, particularly as a beginner is because the assembly structure does not lend itself to be easily assembled. The Author extruded multiple bodies from sketches, which can be a very effective modeling technique, but it was not done in a way that would create a simpler and more sensible assembly structure.

You basically have three groups of parts:

1. Table top with Supports

2. Inner legs with leg brace and big dowel

3. Outer legs.

If you don't want to loose the modeling effectivenes of extruding multiple bodies from one sketch and then turn these bodies into components, then keep these main sketches at the top level..

Are you familiar with Fusion 360's R.U.L.E #1 ?

[Anonymous]

@TrippyLighting No, it's totally OK. I figured you didn't mean it pejoratively, and I am really grateful you're taking the time to educate me on some of these finer points! 

The guy doing the tutorial isn't a hardcore CAD designer, he's just a fellow who does some woodworking at home and mocks stuff up in Fusion before building it in his garage. It's a good place to start for getting a basic sense of how to use the tools, but some of the things he's doing seem really unintuitive or are flatout workarounds for not knowing how to utilize tools the 'correct' way. 

[chrisplyler]

Explanation for why I deleted stuff...because I didn't think some of the stuff was necessary.

Did I delete a model feature? Don't remember that. Maybe so.

Pin slot! Duh! Be right back. Gotta go smack myself on the forehead.