mesh - generating face groups is very time consuming but doesn't appear to use full CPU potential

[jrichels20]

Hello.  A friend sent me a mesh model that has entirely rounded surfaces.  His seat is Free and I gather could not perform a mesh conversion, mine is paid.  The process of generating faces took a long time, several hours (I don't know exactly as it ran over-night).   I noticed that the processor utilization was not that high, less than 20% and only about 12GB of memory, that on a Ryzen 7 5800X (8 cores).  Is there any way to speed up this process?

Thank you.

[TrippyLighting]

I don't think there is any way to speed this up.

Can you share a screenshot of the object?

If "mostly rounded surfaces" means "organic", then creating face groups is not needed.

[Mark532011]

I have this problem too. It is admitedly a large number of triangles (though it is just a small 3dprint figure I downloaded and I did a mesh-reduction) but it takes a long time (10-15 minutes) to do something like a split-body in this case. I would understand it, but the task manager shows 5-15% CPU usage at all times and with very little network or disk usage (see screen shot). I have a Intel(R) Core(TM) Ultra 9 285K (3.70 GHz) with 64gb of memory and SSD only. I would expect it to be using a lot more of my cpu than it is. Is there a setting for multi-core or something I have not set?

Mark

[TheCADWhisperer]

@Mark532011 

Can you Attach the original Mesh file here for testing?

Why do you want to do a conversion? What is the goal?

[Mark532011]

Well, apparently something else was going on as after a reboot and getting out the stopwatch, its now less than 4 minutes. Its still weird that fusion is only using 5% of the cpu during this time but that is an acceptable speed for me. 

attached please find the original .stl file. My ultimate goal is to change it from an open door to just barely ajar so I can 3dprint it. My thought is to cut the door into a separate object so I can rotate it about 80 degrees. 

my steps:

insert mesh (about 1 second)

mesh repair (stitch and remove) 24 seconds

mesh reduce (25% adaptive) 7 seconds

selecting only the door as meshs is difficult, I always seem to get things incorrect, so I convert to an editable body i can cut into pieces

convert mesh (parametric)  1min 34 seconds

construct an offset plane 3.5 inches up from axis (bottom of door)

split body at offset plane 3min 25sec

[TrippyLighting]

Frankly, I would do none of what you described in Fusion. It's just not the right software to do this.

The model you posted is just a frame. There is no door in it:

[TheCADWhisperer]

@Mark532011 

You might be able to do this in Fusion, but the file that you attached does not match your problem description.

[Mark532011]

Sorry, i have several doors I am printing for different areas of the dungron. This should be the right one.

I understand fusion is not the best tool for this, for a one-off I am ok with that. The original issue was that I would have expected my CPU to go to 100% utilization in order to get the work done as quickly as possible but instead it hovers in the 5-10% range throughout the whole operation.

[TheCADWhisperer]

@Mark532011 

The geometry violates real world physics.

The door is embedded into the floor and the frame.

[TrippyLighting]

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@Mark532011 wrote:

...

I understand fusion is not the best tool for this, .

---

That is an understatement for this particular mesh. It's not that this couldn't be done in Fusion, but it would require hours of work and some experimentation, and you might still end up with an undesirable result.

I hope my explanations in the video make sense:

[lauri_barnhart]

Hello, @Mark532011,

Just checking in—did the responses shared by @TheCADWhisperer or @TrippyLighting help clarify your question?

If so, please consider clicking the "Accept Solution" button on the post(s) that solved your problem. Doing so helps others in the community easily find useful answers.

If your question still needs more attention, feel free to reply here with an update. This way, other members can jump in with further suggestions or guidance to help you move forward.

All the best,

Lauri | Community Manager

[Mark532011]

the replies were centered on my doing things inefficiently and not the original issue that Fusion does not seem to be using the CPU very well. At least on my system, long calculations (like splitting a mesh) show a very low CPU utilization when it seems like it ought to be around 100%. But its not a problem since it does do the calculation, more of an observation.

[TrippyLighting]

Did you actually watch the video I created, or could you just not be bothered?

[Mark532011]

I did watch the video (thank you for generating it) - however, its about an alternate method of selecting meshes and has nothing to do with the original discussion (low cpu utilization)

[TrippyLighting]

Agreed, we did not address that. 

Not every algorithm lends itself to parallelization or multithreading. Sometimes things have to be calculated in sequential order. I am not sure generating face groups falls into that category.

An example of an Algorithm that falls into that category is  Markov Chain Monte Carlo. A special variant of that - MLT or Metropolis Light Transport- is used for rendering complex lighting situations (refractive and reflective caustics) in computer graphics. Hence, it hasn't been implemented to run on GPUs. 

[Mark532011]

Hey Lauri, I am not the author of this thread so I don't see a "Accept solution" button. However I feel the issue is closed (and we may in fact have beat this dead horse too much!)

[TrippyLighting]

@Mark532011 If you want to let me know which answer you want to mark, I can do that.

[Mark532011]

your answer, which is essentially "thats the way it is for some operations" seems like its a decent answer. lol, like I said originally...its not a problem, just an observation of something that doesn't run the way I expected it to.

Mark