Low CPU Utilisation

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sudo_ki
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Low CPU Utilisation

Post by sudo_ki »

I have started to use 3Dreshaper a little recently.

I originally imported a .pts file which now saved as an .rsh measuring as 7 GB.

I have found that this program was working rather sluggishly while meshing; to later realise that during some operations it was using very little of my CPU (around 10%). Is this common?

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smacl
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Re: Low CPU Utilisation

Post by smacl »

I don't know about reshaper, but you will commonly see programs running on PCs with multiple cores using just one core. So for an 8 core PC, unless the specific function being used has been written to support mutli-threading, you'd expect to see about 12.5% CPU usage. In our own software (SCC), we write most of point cloud processing to be multi-threaded where it is feasible, but this is not always the case. Meshing is one of the tough ones to multithread. Increasingly, point cloud software is also starting to use the GPU in conjunction with the CPU, so if the CPU isn't going at full tilt it could be because the GPU is doing the heavy lifting. From what I know of reshaper it is actually one of the faster mesh generators out there. You could compare against meshlab if you wanted a point of reference.

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Re: Low CPU Utilisation

Post by sudo_ki »

You are indeed correct about the CPU usage. It is only using 1 thread currently with 0% GPU utilisation.

I find this strange because i have seen it use 80% during some tasks which seem no different in their intent. I suppose that’s a result of what you have suggested.

I guess i will have to keep an eye on it and find the quickest method for processing based on that. I will also check out mesh lab in the mean time.

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Re: Low CPU Utilisation

Post by smacl »

Two reasons that you'll see only one thread used in a piece of software in some places and all threads used in others. The first is that writing multi-threaded code is more difficult and can lead to bugs that making testing far more time consuming, so it is only done where a major bottleneck is identified. Second is that most modern software packages use third party tool kits for many functions, so they're stuck with single threaded code until such time as the third party SDK is updated. Writing a good mesher that is single-threaded is difficult enough, writing a good multi-threaded or GPU based mesher far more so.

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Re: Low CPU Utilisation

Post by gilles_3DR »

Hi there,
In 3dreshaper, most algorithms are multi-threaded (when possible). Unfortunately, 3d meshing is not...
We have some ideas to do it but will require a lot of R&D...
Usually, my advice to speed-up meshing is to use a greater value of triangle size (this part of the algorithm is not multi-threaded) and then refine the mesh to add details (multi-threaded algorithm here).
Maybe try with a smaller part of the point cloud to adjust triangle size and refinement parameters.

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Re: Low CPU Utilisation

Post by sudo_ki »

It maybe be time to overclock my cpu ^^

Thank you both for you input.

As a side note; when i have come to refine the mesh (mesh\refine mesh\) the option to refine using point cloud seems to be more often than not grey’d out. Why would this happen?

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Re: Low CPU Utilisation

Post by gilles_3DR »

My first guess for the button to be greyed out would be that you only select a mesh.
In order to run this command, you need to select a mesh AND a point cloud.
Gilles

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Re: Low CPU Utilisation

Post by sudo_ki »

I thought that was the case and selecting both enables me to refine it when it is available.
I haven't yet found the common reason why I can't but I will update if I do.

Thanks again for your input guys.

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