topic Re: When a newer version of Fusion completely breaks your model... in Fusion Support Forum

When a newer version of Fusion completely breaks your model...

mroek — Wed, 20 Dec 2017 00:52:30 GMT

This is more of a rant than anything, perhaps unjustified, I don't know.

Back in May I worked on a quite large and complex model, and I do remember struggling to create some of the geometry. I more than likely did stuff in suboptimal ways, but I always ensured my timeline was free of any warnings and errors. And I even used to do a full recompute regularly, just to make sure (even if that takes a couple of minutes on this model).

Today I opened that model again, thinking I'd do some more to it, and it opened cleanly and looked as when I left it. But then I did a recompute all, and the (very long) timeline now has loads of errors. A lot of them are most likely linked to just one issue further up in the timeline, but I dread even to start fixing this mess. In several cases errors can stem from an operation that goes wrong in a way that in itself does not throw an error, making it even harder to actually find the root cause.

The only way I see to even start fixing it is to keep the model open in two tabs, one without having done the recompute, just as a reference for what each feature does, and then try to fix that in the recomputed (and badly broken) model, going back and forth, stepping the timeline in sync. Tedious.

Is this to be expected? I get that Fusion itself receives bug fixes all the time, but it sure is annoying when older models are broken by newer versions of Fusion. There has been quite a few new versions since I last worked on this project, so I have no clue when the errors crept in. I know the model is in many ways a mess, but at least it was an orderly mess until Fusion broke it...

I'm not asking for help to fix this (and I don't want to share the model in public), I'm just wondering what you guys do to avoid stuff like this?

Here's just a screenshot so you have an idea what this looks like:

Re: When a newer version of Fusion completely breaks your model...

paul.clauss — Tue, 02 Jan 2018 21:46:11 GMT

Hi @mroek

Thanks for posting! I apologize for the delay in response.

Changes and errors in the design are not intentional with updates - this is not the expected behavior, but I do sometimes see this type of behavior. While it is difficult to say why doing the Compute All after Fusion updated triggered the errors in your design, I do have some thoughts that may help.

For this model, I would simply kill the design timeline and work in direct modeling mode. This should clear up the warnings and errors you are seeing nicely, as they appear to be related to some reference feature being lost early on in the timeline. You can remove the design history from a file by right clicking the top level component group in the browser and selecting "Do Not Capture design history." You could then use the direct modeling tools in Fusion to make changes to the assembly model.
Being careful to respect RULE #1 can also help make your designs more robust.
When working with relatively complex assemblies like yours, I like to point folks to the Fusion 360 Assembly Master Class video - this video explains the best practices for assembly modeling in Fusion and may help you avoid errors down the road.

Hopefully some of this helps! Please feel free to reach out whenever you have questions.

Re: When a newer version of Fusion completely breaks your model...

mroek — Tue, 02 Jan 2018 22:58:26 GMT

@paul.clauss Thanks for taking the time to answer. Yes, killing the timeline does work, but I really don't like the direct modelling mode. I'm just really fond of having the history, and I haven't learned to like direct modelling (at least not yet).

That said, I ended up spending some hours repairing the model, my OCD forced me...

Re: When a newer version of Fusion completely breaks your model...

paul.clauss — Tue, 02 Jan 2018 23:15:46 GMT

Hi @mroek

Thanks for the response - I can't handle seeing yellow or red down there either! It stresses me out. Glad to hear you got everything working, but sorry to hear that it took some time.

I wasn't a huge fan of the direct modeling at first, but the more I use it, the more I like it and see more uses for it! I would keep playing around - please let me know if you see any other models damaged by an update.

Re: When a newer version of Fusion completely breaks your model...

TrippyLighting — Wed, 03 Jan 2018 03:11:50 GMT

@paul.clauss wrote:

Hi @mroek

Thanks for the response - I can't handle seeing yellow or red down there either! It stresses me out. Glad to hear you got everything working, but sorry to hear that it took some time.

I wasn't a huge fan of the direct modeling at first, but the more I use it, the more I like it and see more uses for it! I would keep playing around - please let me know if you see any other models damaged by an update.

I am glad I am not the only one who despises red and yellow icons.

Direct modeling can be very powerful and it would be nice if the direct modeling capabilities in Fusion 360 would receive some needed development attention.

Re: When a newer version of Fusion completely breaks your model...

mroek — Wed, 03 Jan 2018 09:15:07 GMT

@TrippyLighting I'm sure direct modeling can be very powerful, but somehow I have a notion that it is inferior to history-based modeling. It is kind of "forward editing only", so if you need to revert something you did a whicle back, you need to edit it back to how it was, instead of just changing (or removing) a timeline feature. Even if the end result is the same, it feels to me like a less precise way of modeling. I realize this is most likely just in my head, but that's how it is (at least for now).

Re: When a newer version of Fusion completely breaks your model...

TrippyLighting — Wed, 03 Jan 2018 12:23:00 GMT

It is inferior to timeline based modeling in Fusion 360 only.

There is one major misconception and it is also spread by number of video tutorials for Fusion 360. T

hat misconception is that parametric modeling is intrinsically connected to timeline, or history based modeling.

I'd invite you to watch some Spaceclaim tutorials on YouTube. First you will notice that many of the direct modeling functions look like direct functional copies of Spaceclaim tools. The similarity is staggering!

Then you will notice how much more powerful Spaceclaims direct modeling tools are than Fusion 360's tools. You'll also notice that Spaceclaim models can be fully parametric.

I really wish that area would receive the same amount of development than others.

The trouble with timeline based modeling is that in that timeline every action is parametric and associative, even when there is no need for it. You don't have a choice over what you want to be associative or parametric. If you use User parameters and edit one Fusion 360 recalculates the entire timeline. I've come across several cases where I had to break up a design into smaller pieces, despite the clear disadvantages of doing some, because Fusion 360 is very slow when doing so.