Fusion freezes but does not use all resources

[realkpavel]

Fusion often freezes when editing bodies converted from a detailed mesh. I know it doesn't handle those kinds bodies well, but during those freezes Cpu usage does not go over 15% and RAM usage stays below 70%. Is this normal, or is there a way to make fusion use more before freezing? 

[saito.kh]

Hi @realkpavel ,

Thank you for posting and welcome to the community!

Sorry to hear that!  I would like to take a closer look at this on my end.  Would you mind sharing the model converted from mesh?  If it is okay with you, can you please post a public link to the model in this thread?  You might like to send the link to me directly (kanehiko.saito@autodesk.com).

** Please make sure to enable the "Allow an item to be downloaded" option before you copied the link.

Also, can you share a bit more information about how you edited the bodies?  I would appreciate if you created some screenshots or a Screencast to capture how you were working.

If you have any questions, please let me know and I'm happy to help!

Thanks.

[realkpavel]

I'm sorry, I can't access the computer right now so I can't share the file,
I'll post the link here as soon as I can. For now I can only share the
viewing link from the mobile app. The problem manifested while selecting
the model, and was most severe (freezing for about 30 minutes) when
exporting the file to an stl.

https://myhub.autodesk360.com/ue2b9ffec/data/permalink/DTfe124QTfe25c5e0c1dcbde35965c7bbe7b

[realkpavel]

Ok, so I managed to somehow get the file via teamviewer. The "bad" part is Component 4. The worst freezing happens when selecting the object to export to stl, not while exporting it. 

[realkpavel]

And I don't know if does apply at this occasion but the license of the original stl said I have to say it was made by JLTX when I upload the file anywhere so I put it here to be safe

[saito.kh]

Hi @koumes.mates ,

Thank you again for posting in the community!

I tested with your mode, and I saw it was a bit slow in the response.  I created a Screencast to capture how it worked on my system as the following: Intel Core i7, 16GB RAM, NVIDIA Quadro M1000M, Windows 7, Fusion 360 R2.0.5357

In order to further investigate this, can you please share your system information?

Thanks.

[realkpavel]

Thank you for the reply! My system specifications :

AMD Ryzen 5 1600x 

8 GB of RAM 

Nvidia GTX 770

Windows 10

Fusion version 2.0.5357

I did some more testing and the CPU usage on some cores did briefly spike to 100%, but not for the entire freeze and not on all cores. 

[saito.kh]

Hi @realkpavel ,

Thank you for your reply!

Currently I am discussting this with my colleagues.  I will get back here once I have something to share!

Thank you for your patience.

[TrippyLighting]

What is it you want to do with this model ?

Fusion 360 is not a software that has mesh editing at its core and Autodesk Meshmixer might be a better alternative.

[realkpavel]

Hello, I just wanted to know why it doesn't use all of the processor power and RAM before it freezes, and whether I can somehow make it use the resources better. I know that using Fusion to edit STLs is by far not ideal, but this particular model is a machine component and the edits I make need to be of precise dimensions. 

[jeff_strater · Accepted solution]

@realkpavel - the algorithms for operating on a BRep model are inherently single-threaded, for the most part.  Modern computers have multi-core processors, but these algorithms can only look at one face at a time, currently.  So, the reason that it appears that not all resources are being used is because some cores are idle.  As @TrippyLighting , using the existing Mesh to BRep workflow in Fusion is not recommended for large mesh bodies.  This one has 40,000 faces and 60,000 edges.  This is a fairly large BRep model, under the normal BRep workflow.  For instance, the cylindrical faces in this model look like this:

If these cylinders were modeled natively, each of them would have only a single face.

Even given the large size of this model, I was able to work with it relatively well on my machine.

[realkpavel]

Thank you! If the process is single-threaded, it makes sense that it doesn't show up as 100% usage on what is effectively a 12-thread processor. I'll look into overclocking the processor for more single-thread performance. 

[infoMA5R8]

For me, fusion360 only uses 5 to 10 percent of my CPU when making 2d projection drawings. You write that the algorithms are single threaded and that because of this fusion360 does not use all CPU resources. This story is not correct because when I look at every thread of my cpu there is not one thread that is heavily used. My GPU is hardly used either. Can you tell the real reason why fusion360 is so slow?

[TrippyLighting]

Can you explain what a "2D projection drawing" is and perhaps post an example design or screenshot ?

[infoMA5R8]

In my 2D drawing I use section views with many components. Fusion360 is very slow to generate these views.

[TrippyLighting]

Ahh, yes Fusion 360's Drawing environment is very slow!

However, this does not have anything to do with the modeling operations in this thread and the issues explained by @jeff_strater 

[infoMA5R8]

According to Jeff, only part of the CPU is used because certain algorithms are single threaded. If a calculation is single threated then at least one thread should be used intensively. Since this does not happen for 2d projection drawings as well as for 3d modeling, Jeff's explanation is incorrect.
But I understand from your answer that it is true that 2d projection drawings in fusion360 are very slow.
I think everything in fusion360 is slow.

[jeff_strater]

---

Jeff's explanation is incorrect.

---

My explanation is not "incorrect".  If you look at the original post of this thread, it refers to modeling operations on a BRep.  Most BRep modeling operations, are, indeed, single threaded.  I know this from direct experience with the code involved.  Yes, there are some operations in Fusion which are multi-threaded.  For instance, the faceting of models (creating 3D graphics from 3D body geometry) is multi-threaded.  So, there will be times when CPU usage does show higher core utilization.

@infoMA5R8 - you have glommed onto this thread and attempted to claim that my statement about single-threaded modeling operations is "incorrect" when applied to 2D drawings.  I did not say anything about 2D drawings in my response. Please, in the future, be more accurate when accusing others of incorrect information.

[TrippyLighting]

---

@infoMA5R8 wrote:

According to Jeff, only part of the CPU is used because certain algorithms are single threaded. If a calculation is single threated then at least one thread should be used intensively. Since this does not happen for 2d projection drawings as well as for 3d modeling, Jeff's explanation is incorrect.
But I understand from your answer that it is true that 2d projection drawings in fusion360 are very slow.
I think everything in fusion360 is slow.

---

Jeff's statement is spot on. I belive the operations are really single-core and not a single thread, (@jeff_strater please correct me if I am wrong)

Whether a core can be more utilized depends on very many factors, e.g the algorithm itself, its code size, memory utilization (size, frequency of read/write) etc.

There is just so much optimization even a modern compiler can squeeze out of code and processors.

The geometric modeling kernel used for 3D modeling operations is completely separate from the sketch engine, which is completely different from the ode used for 2D drawings. Modern CAD software is very complex!

I disagree that everything is slow in Fusion 360. Broad statements without data don't serve anyone.

[infoMA5R8]

A Core is broken down into threads, so your story won't hold if Jeff is right.
You also write:

Whether a core can be more utilized depends on very many factors, e.g the algorithm itself, its code size, memory utilization (size, frequency of read / write) etc.

There is just so much optimization even a modern compiler can squeeze out of code and processors.

So you are saying here that fusion360 does not have good algorithms and does not make good use of memory and does not use a modern compiler?

Furthermore, I understand that the geometric modeling kernel is separate from the sketch engine, but Jeff says that fusion360 uses single thread algorithms and that because of this fusion360 only uses a very small part of your cpu, but this cannot be the only reason.
Furthermore, it is of course no excuse that a CAD program is slow because it is complex.
Compared to CAD programs, fusion360 is slow, and when I look on google, I'm not the only one that find this.

It has now been over a year since someone else created a topic with the following name: "Fusion freezes but does not use all resources".

and still fusion360 has this problem for which there is no solution. (Some even try to overclock their cpu: (strange that this is necessary with a professional CAD program and a fast system).