Project with just 29 bodies using 7000+MB of memory & freezing

[samathon]

Hello, I'm having an issue where my project is using up a ton of memory and becoming unresponsive. From the moment I open the project (before performing any operations) it uses 7GB or more of RAM. Doing a task such as modify > split body sometimes works just fine, and sometimes makes the whole program unresponsive, taking 5 minutes or more to complete. Even toggling a body's visibility or saving the project can make it freeze up for long periods.

I'm still pretty new to Fusion 360, and most of what I know about it was learned by playing around with the tools using trial and error, so I'm wondering if something about the way I use the program is incorrect and creates problems like this. The project only has 29 bodies in it, which doesn't feel like enough to cause this kind of performance issue, but the project history is very long and complicated; I'm wondering if that has something to do with it?

My computer is using an 8th generation Intel i7, a 1080ti GPU, and 8GB memory.

Here is a link to the project, if that helps:

https://a360.co/2zNQTOF
I'm not sure how to actually get the project file itself to share.

[TrippyLighting]

I had to stop Fusion 360 after about 5 minutes with all fans of my MacBook Pro running at full RPM.

Can you show screenshots of the fully expanded browser and those bodies?

[samathon]

I'm sorry to hear that; thank you for trying to open it!

I'm now unable to open the most recent version of it (V6), which was saved about 40 minutes after the previous version but seems to have made the problem much worse. I can still open V5, though it takes a few minutes.

I've attached a screenshot of the browser with the body folders fully expanded; there are also 34 planes in 'Construction' and 50 sketches.

[TrippyLighting]

That looks OK at first sight.

How does the timeline look like?

So save this under a different name and delete the timeline in that newly saved file.

Do you notice any difference?

[samathon]

The timeline is extremely long, I would need way more than three screenshots allowed to capture the whole thing!

Can you tell me how to delete the timeline? I've tried looking this up to no avail!

[TrippyLighting · Accepted solution]

I don't see how the timeline can be extremely long for design with 29 bodies, which don't look particularly detailed.

Right-Click on the root of the browser and select :

 

[samathon]

That did it! The project is still a *tiny bit* slow, but for the most part, right back to normal and fully usable. Thank you very much! Unfortunately, that does mean I no longer have a timeline.

Do you know why removing the timeline would fix the performance?

Also, removing the timeline added a bunch of extrudes to the browser; can these be deleted, or would that affect the model?

The reason the timeline is so long is because I've been iterating on this design for a while, 3d printing it, then making changes. I guess I don't really have much of a point of reference, but for me the shape is a bit complex. Here's what it looks like so far:

[TrippyLighting]

Can you share the timeline free design?

[TrippyLighting]

Also, your design did open after a long time:

 

 

Then it took a long time for my eyes to stop bleeding!

You did not iterate, you built invalid geometry. Your timeline is littered with errors and warnings. Itis no surprise that this design was slow. No supercomputer is going to help if you don't keep a clean timeline. When these things turn red any yellow you should go back at the very first instance and fix the problem, not just plow on!

[samathon]

Here's the one without the timeline:
https://a360.co/3g32J8f

Well this is embarrassing! I certainly don't remember seeing all that red and yellow in my timeline, I don't know how I missed it. If I do see it in future projects, I'll definitely be sure to do as you say and go back to try and fix the error.

Sorry about your eyes!

[TrippyLighting]

I'd redesign this from scratch with a timeline using components, not just bodies.

[samathon]

Well I'm pretty close to the end of this design I think, so I'll most likely just finish this up and close it off. But for future projects, I'll have a look into the difference between bodies and components and when I should be using each; I hope this doesn't hurt you to hear, but I've never made any components, only bodies!

Thank you very much for all your help. I was afraid I had lost many hours of work.

[TrippyLighting]

---

@samathon wrote:

 I hope this doesn't hurt you to hear, but I've never made any components, only bodies!

---

LOL. I am OK 😉

Here's a link describing the differences between bodies and components.

When done absorbing that, familiarize yourself with Fusion 360 R.U.L.E #1

[samathon]

Thank you for the links! They both link to the first page, I think this was meant to be the second link, though:
https://forums.autodesk.com/t5/fusion-360-design-validate/fusion-360-r-u-l-e-1-and-2/td-p/6581749

I'll definitely read through these and adjust how I work! Thank you so much again!

[jeff_strater · Accepted solution]

@samathon - I don't know if you are looking for more advice or not, but I thought I'd add to @TrippyLighting 's comments, and try to explain why what you did uses so much memory.

Here are some answers to these questions:

"Do you know why removing the timeline would fix the performance?"

The errors/warnings are definitely a factor - these can cause Fusion to "cache" the last good version of a feature's input, so that it can keep computing even if the feature fails.  For instance, if you have a Combine of two bodies, that can cause Combine to keep a copy of the failing input.  If that is a big body, that can get expensive in terms of memory.  Second, and more importantly, Remove is a timeline-based feature.  That means, if you roll back the timeline before the Remove, the body is still there.  So, Fusion has to keep that "removed" body around in the file and on memory.  I went through the timeline and counted:  There are 329 Remove Body features in this design.  So, while the design has "just 29" bodies in it at the end of the timeline, there are 329 bodies that are also kept around for history reasons.  This is partly why the design is 85.5 MB on disk, and takes 7GB to load.  That is also why removing the timeline "fixes" the problem - all those errors, and all those Remove features are now gone, so you are back to just the 29 bodies that remain.

"Also, removing the timeline added a bunch of extrudes to the browser; can these be deleted, or would that affect the model?"

Those are "direct modeling features".  You can't delete them, that will damage the model, but you can select all of them and right click and choose "Dissolve".  This keeps the geometry, but removes the feature from the browser.

"The reason the timeline is so long is because I've been iterating on this design for a while, 3d printing it, then making changes. I guess I don't really have much of a point of reference, but for me the shape is a bit complex"

This, I think, is the real issue with this design.  I took a look at the first part of your design, just stepping through the first 30 or so features.  Below is a screencast that shows what is going on in those features.  I would characterize this style of design as "direct modeling but with the timeline on".  Direct modeling is what you would do in a model with no timeline, no history.  If you don't have the ability to go back and edit a sketch or a feature, etc, you would do these types of operations - adding and removing material incrementally.  It is a perfectly valid way to model, but with the timeline turned on, you are capturing each of these as a separate feature.  This is expensive.  You should use the timeline to enable you to go back and edit the features you have so far, rather than to just add and remove material by adding more features to incrementally change the shape of a feature.  If you don't have any intention of going back to edit those features, there is no real reason to capture those features.

At the end of this set of features, there are a lot of duplicate bodies.  I did not go any farther, but the duplicate bodies might be an indicator of where some of the volume of data comes from.

Don't take any of this as criticism, just trying to explain what you are seeing.

[samathon]

That is incredibly helpful; thank you so much for taking the time to write this out for me!

It was kind of my expectation when opening this thread that the issue was somehow caused by my workflow, and it seems like that is in fact the case. The modelling workflow of adding and removing material feels intuitive to me, so I think I'll stick with direct modelling (but with the timeline off!) for now.

The timeline does seem powerful, but I've been a bit afraid to use it; I think I have a fear of going back and changing an earlier shape or value, only to accidentally cause some butterfly effect issue down the line. At some point I'll get around to playing with it more, but I think I may need to watch some tutorials just to get back to the level of confidence I have with my current workflow which comes naturally to me.

Again, thank you very much for your helpful explanation; it makes perfect sense now.