Joints Forgotten All of A Sudden

[Anonymous]

Recent issue with Fusion. This part had all the appropriate joints and was having no issues until today. But for whatever reason they seem to be "forgotten" and now they won't remain in place. Tracing back in the design history shows at one point adding a joint causes everything to move. And then at the end of the design tree I can move a few of the parts around as if they never had any joints. Just to reiterate, I designed this weeks ago and everything was in the correct place but I opened it up today and everything had moved. 

I can't seem to post a .f3z it says "content type does not match its file extension and has been removed"

Thanks, 

Ross

[innovatenate]

Hey Ross,

Can you just use the share link or possibly compress the file into a zip and then upload it to this thread?

Thanks,

[Anonymous]

http://a360.co/2zKsOqa

Didn't know you could do that actually. 

Thanks!

Ross

[innovatenate]

In Fusion 360, the components in subassemblies are not rigidly constrained in the parent component group or top level assembly. This allows you to quickly make changes several layers down in the design tree without much effort. However, it does add some complexity because the component may need to be "locked" down with every tree layer you add. The ground command only fixes that components origin to the next level up's origin, not the top level origin.

An easy trick I use to make sure things won't move is to create an As-Build Rigid Joint between the origins of components and subassemblies. I'm also a fan of the rigid group command to quickly fix a bunch of components relative to one another.

It's a quick way to make sure that a component origin is fixed in place all the way to the top level of the assembly.

If you watch this class, there are lots of great tips on how to build a parametric subassembly with a skeleton body and work with joints. I think it would be a big help.

http://au.autodesk.com/au-online/classes-on-demand/class-catalog/2016/fusion-360/pd19577#chapter=0

In this particular case, I can see that the position of the components are not fully defined. In the below screencast, I use the as-built joint to quickly lock down the frame assembly.

From what I can tell, you are gathering components into a unique grouping system in the browser. Can you elaborate more about the intent behind this approach? 

I hope this helps.

[Anonymous]

Nathan, 

Thank you for the in-depth explanation, I wasn't aware of the complexity of joints in regarded to multiple nested components. I will for sure watch the video. 

This isn't my first design iteration of this particular assembly. I notice in my earlier versions, and in general with other assemblies, that I often switch visibility on/off of like parts and related sub-assemblies at a time. When designing assemblies with a higher number of parts I find it tedious to have to turn visibility off for individual parts (I am aware of the isolate feature but sometimes I need multiple components visible) so grouping them by part and by subassembly makes organization a bit easier for my workflow but also my mental state haha.

Thanks for the help.

-Ross 

[innovatenate]

Since the assembly tree structure can influence the degrees of freedom, it may make more sense to use Selection Sets to help quick change the visibility of certain components.

Using Selection Sets with the keyboard shortcut for visibility (V) is a really quick way to toggle the visibility without having to rely on the browser structure. It might be worth checking out if you haven't yet.

I hope that helps!