BUG: bodies disappear from view and navigation tree

[petedXDG8M]

I apologize in advance for this incomplete report. I don't have the time to construct a proper, simplified reproducible case, especially not after I wasted a couple of hours just figuring out how to work around this bug. But I wanted to share what I think are the most salient details, to assist in fixing the bug.

The problem: I was in the middle of editing a component in my design. I needed to go back in the timeline to break one of the bodies into smaller pieces, so I could adjust a later edit (adding a chamfer, but excluding certain segments of the edge being chamfered). When I completed my edit, which involved adding some more lines to a sketch, editing the existing extrusion to use only three sub-profiles of the sketch, and adding a new extrusion using two other sub-profiles of the sketch, the two new bodies created in the second extrusion disappeared from the view, while the other three bodies disappeared from the navigation tree.

Selecting the two bodies in the navigation tree did not select them in the view, and the three visible bodies in the view did not seem selectable. Clicking on them only selected individual parts; I couldn't get Fusion 360 to select the whole body.

I believe that whatever was going on, was likely related to the fact that after editing the sketch and the extrusions, later features in the timeline wound up with warnings or errors. But even after I visited each feature, editing it to correct the issues, the problem with the missing bodies did not resolve itself.

I tried a number of things to get the bodies to come back, but ultimately I wound up changing two pieces of my workflow:

1) I deleted all the features after the sketch, and started all over. I reasoned that possibly even though I'd fixed all the errors, one or more of them had corrupted some internal data. NOTE: one of the errors was "UNDEFINED ERROR".

2) Part of my edit to the sketch involved mirroring some lines using the Y axis as the mirror line. This seemed to work, but when I was editing the sketch the very last time, I decided to use the ZY plane instead of the Y axis as the mirror line. Here, I reasoned that even though it should be reasonable to assume Fusion 360 understands when I'm in a sketch, mirroring on an axis that is not actually co-planar with the sketch should just use the projection of the axis (and indeed, that's what Fusion 360 seemed to be doing), it's possible that that situation confuses Fusion 360, and that by being explicit and using something (i.e. the ZY plane) that actually intersects with the sketch plane would avoid the problem I was having.

Of course, without a proper repro case, I understand that it's entirely possible *neither* of those changes to my workflow are actually what resolved the problem. But that's the only information I can think of that would be relevant.

I hope that this is enough to get the developers on the right track and fix this problem. It's very frustrating to have Fusion 360 appear to be working fine, and then without any errors being present in the timeline, just stop showing bodies one's constructed in the component.

[TheCADWhisperer]

At the risk of stating the obvious - when you aren’t sure of the best move it is often best to stop and post your file for the numerous experts here to have a look. It can be very helpful to get many different eyes on a problem.

Also, ensure that you have versions so that you can return to earlier revisions if things get scrambled.

[petedXDG8M]

Thanks! I'm sure that's good advice. In fact, I do save multiple versions, and it was relatively simple for me to back up to a known-good state and start again. That's how to was able to find a sequence of design steps that accomplished what I wanted but without triggering the problem.

As far as sharing the document goes, yes...I'm sure that's also very good advice. Unfortunately, when one is in the middle of trying to get something done, that's not exactly the first thing that comes to mind. For me, since I'm relatively new to both the program and the forum, it's not even clear to me how I would share the document, given the cloud-based approach. "Save As..." seems to just put a new copy in my design portfolio. Would I need to use the "Export..." command instead? Which format is appropriate for sharing here?

The issue isn't that your suggestion isn't good; I'm sure it is. It's just that being new to this, faced between the choice of working through my problem on my own, or shifting gears and trying to learn how to correctly share the state of my design and seek help from others, especially given I'm not even sure that whatever corruption was going on would be accurately preserved in whatever data I shared, it seemed more practical at the time for me to choose the former.

And in this case, it was. I was able to get the design working, by going back in the design, deleting the things that seemed to be messing up, and starting again, this time being more careful to try to avoid things that I thought might confuse Fusion 360. So the advice from others on that point was unneeded.

The point of this post is not for me to receive advice about how to fix the problem, though of course if anyone has information along those lines, I'm happy to learn something new.

Rather, it was to convey to the Fusion 360 team information that I have and which I believe could be useful for them in the pursuit of finding and fixing the bug in their program.

And to be clear: whatever else I might have done wrong, I do view it 100% as a bug in the program for it to not show bodies that I *know* are present, and for the navigation tree to not be in sync with the rendered editable view.

[TrippyLighting]

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@petedXDG8M wrote:

... Would I need to use the "Export..." command instead? Which format is appropriate for sharing here?...

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Export as .f3d (or .f3z if is is an assembly with externally referenced files) and attach it to a forum post.