Ground in Fusion 360 will not work

[KerryHarrison]

Hello,

I’m building assemblies and Fusion 360 and for some reason the ground function stopped working. I insert a component and position it where I want it. Then in the browser tree I hover over the component name, right-click and select ground. The pushpin icon appears but I can still move the component around so it’s not grounded.

I can add the second component and joint them together but then I can move both of them around. Even if I ground both components I can still move them.

Any suggestions on what I might be doing wrong.

Thanks,
Kerry

[James.Youmatz]

Hi @KerryHarrison,

Do you think you can go ahead and post the model (as well as a screencast documenting your steps)? This will allow us to try and reproduce your steps and see what is causing this issue.

Thanks,

[jeff_strater]

It's hard to say for certain without seeing your design.  If you share it, we can take a look.

One thing to remember, though is that Fusion always has "flexible subassemblies" (for lack of a better term).  That is, if you have a design that looks like:

• Root
•     SubAssy1
•         Part 1
•         Part 2

If you ground SubAssy1, Part 1 and Part 2 are still free to move.  Grounding SubAssy 1 only grounds things at that level (in this case there really is nothing at that level, unless SubAssy 1 has a Body.  So, if you want Part 1 and Part 2 to stay put, you need to ground them.

If it's not the sub-assembly issue, then there may be a bug, we'd be happy to take a look

Jeff Strater (Fusion development)

[KerryHarrison]

Here's the model where ground is not working  - http://a360.co/1NGBKxv

Heres a model where ground is working - http://a360.co/1ikyeLS

I recorded a screen cast showing what I'm doing and uploaded it. However I'm not sure where it uploads to. Hopefully you folks know where to find it. It's called ground not working.

Thanks,
Kerry

[KerryHarrison]

Just received an email with a link to the screen cast. Here it is -

http://autode.sk/1LklBvX

Kerry

[jeff_strater]

This is the case that I was describing in my reply.  In your case where it appears to not work, you have grounded the subassembly:

You will need to ground the leaf-level components to get them to stay put.  Here is a screencast of doing that:

Thanks,

jeff

[KerryHarrison]

Ahhh the light dawns. I get it now.

Thanks!!

Kerry

[PhilProcarioJr]

Jeff, if the sub assembly is grounded shouldn't anything under it also be grounded? What is the reason for the current way it works?

[jeff_strater]

Sorry for the delay, I've been traveling in China.  And, well, to be honest, a bit of procrastination...

Yes, I understand your question, and it is a valid one.  It is reasonable to ask why grounding a subassembly does not automatically ground all the components under it.

The main reason we do this is that a Fusion component, unlike a subassembly in other CAD systems, can also have a body of its own, as well as child components.  So, ground only applies to the bodies in the component being grounded.  We want to make the child components free to move on their own.

We have discussed the idea of allowing a "recursive ground" option to the Ground command.  That is:  When you ground a component that has children, prompt to ask whether you want this ground to also be applied to the children (all the way down).  One problem with this approach is that this would only cover existing components.  It would not, then, ground any new components added to that "subassembly component".  We could also implement this at compute time, not just at command time.  All of these are possibilities, but so far, none have risen to the top of the heap of our priorities.

Jeff

[PhilProcarioJr]

Thanks for the reply Jeff, this gives me a few ideas to post to the idea station.

[Anonymous]

Hi Jeff,

Thanks for posting this eloquent explanation, you just ended several hours of puzzlement and frustration. 🙂

This is a one of those many little F360 details (quirks?) that desperately needs be captured in a design document for new users.  At first blush F360 looks a lot like a traditional parametric MCAD package, but the timeline and bodies vs components paradigms (and possibly more) mean it really is a very different beast.  I get that to accomodate the added flexibility of those elements, there are a lot of differences in the data architecture and workflow required - but absent a document that explains (exactly as you have done in this post) the reasons underlying a particualr behavior and the resulting workflow requirement - even users with years of MCAD experience will keep smackign their heads against these hidden obstacles.

Just a thought, but would Autodesk ever consider some sort of crowd funding option to get the F360 documentation really done properly?  I'd certainly ante up . . .

[liujac]

Hi,

I wrote an AddIn that can ground or unground the selected component and all the sub components. You can download the addin from the attachment and unzip it. Follow the video below to add and run the addin.

Regards,

Jack

[TrippyLighting]

Thanks for that addin. I'll try this out.
In general that Addin should really not be necessary. When you open the Rigid Group command there is a littel checkbox "Include child components" that should actualy do this.

It just is not working an if I understand @jeff_straters comment in another thread correctly he logged that as a bug.

[jeff_strater]

Yes, the "Include Child Components" checkbox is not working correctly.  This is a bug, and we are working on it now.  Sorry for the confusion this bug has caused.  I can certainly understand why this causes confusion - the option clearly is indicating the exact functionality you want, but doesn't do it.

Jeff

[neljoshua]

I am glad that I came across this post.  This issue has been confusing a co-worker and I for a few weeks.

I have a related question: why when I create an assembly, ground one component, and rigidly join the others to it, does grounding the assembly when inserted into another assembly not work?  I realize that a ScreenCast may be helpful, so here it is:

As you can see, I have created a simple assembly (for a purchased condenser) and inserted it into another assembly (which is a fan shroud we build in-house).  The condenser itself is fully constrained/joined and grounded.  When I insert it into another assembly and ground the condenser (as I would like it to be the reference point), it is free to move around.  The only way to fix this is to ground one of the components of the condenser--which makes no sense to me, as that assembly is already grounded.

[jeff_strater]

Hi @neljoshua, I apologize for the delay in responding.

This is a very good question.  The answer is a mix of user requirements, plus some implementation problems.  But, your basic understanding is correct.  A ground is not honored when inserted into another design.  This is really, to be honest, a limitation of the way that we implemented the ground feature, before Fusion supported distributed designs, and we just found that we ran into problems trying to implement promoting this constraint into referencing designs, so it never got implemented.  There were also some user-level questions about what happens when you insert multiple levels of subassemblies, etc.

I can't promise that we will fix this soon, but it is on our list.  I apologize for the inconvenience of having to re-apply the ground.

Jeff

[Anonymous]

Okay, I understand how the ground function works now, but it seems cumbersome for large assemblies to have to ground all components.  Is Fusion pushing the user to fully define all components in each assembly?  Can you give me an example where a fusion component with two bodies and one body grounded is useful?  

Thanks!

[ningman]

Glad I found this post.  This behavior was driving me nuts.

This solution, BTW, seems like a work-around that should have been corrected by now.  It is extremely non-intuitive.  If you ground the top-level assembly (especially if the assembly has all subcomponents fixed in place with a rigid group AND linked to another parent design stored separately), intuition strongly suggests that all of the subcomponents should be grounded together.

[lkokkone]

This is a really annoying feature. Is there any update on this?

[TrippyLighting]

Not sure what exactly you are referring to as an annoying feature.

The function behind the  "Include child features" check box has been fixed over a year ago.