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Javier PL avatar image
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Javier PL asked Javier PL commented

PF Create Object vs 3D Source

All,

Recently, while I was modelling the creation of some kind of wind power substructure, I decided to do it as always: first customising my flowitem and, later on, creating the 3D object through a"Create Object" activity in m Process Flow. All of a sudden, an issue came up here: the 3D model of the flowitem was extremely heavy, so every time there was a token in the aforementioned activity about to create another item, the model got stuck for a split second.

Afterwards, in order to solve it, I decided to first create a Box flowitem and change its shape right after with a "Change Visual" block, which surprisingly didn't take any noticeable extra-time for the simulation already running. At that point, I was just glad at having it solved so I no longer wonder about it.

However, I have just come across the fact that, if you recycle any flowitem in a 3D sink, the process flow "Create Object" activity does not reuse it to optimise the running. Put differently, I guess the "Create Object" PF activity works in a different way compare to 3D Source when creating.

Thus, some questions come to my mind regarding this issue:

  1. What was the cause of the drag on the model performance in my case? In other words, what's exactly the difference between creating a non-optimised customised flowitem or a default softer one (i.e. box) and changing its shape afterwards? I suspect has something to do with splitting the operation (first create, then set 3D model) but, if the 3D model is equally heavy, same amount of memory is allocated, isn't it?
  2. Why PF "Create Object" activity does not take recycled flowitems as source does?
  3. And, a little bit beyond this, is there any difference between recycle flowitems once the process is finished or keeping them hidden in the model in terms of performance hit? Just in the case they are being recycled but not reused.

Thanks in advance,

Javi

FlexSim 19.0.0
sourceflowitemscreate objectperformanceperformace
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Cliff King avatar image
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Cliff King answered Javier PL commented

Quite the questions Javi. You've really put some thought into this!

I'm not sure what help I can give other than to confirm that yes the PF Create Object activities do not look for recyclable items like the 3D Sources do. I'll also tell you that there has been talk to remove the recycling capability of the 3D sources as well, because it 1) can cause lots of problems, 2) there is evidence that it doesn't help that much, and 3) in some cases, is actually slower.

I can't imagine why it would be faster to change a 3D shape rather than start with a different 3D shape. It must be something else.

In the next version of the software (20.1 I think) we are offering some really nice tools for analyzing a model to determine what contributes the most to runspeed and memory usage. I don't know much about it, but @jordan.johnson does, and he would be able to take a model you send him and run it through the development version of the new software and possibly provide you with a report and some ideas for how to speed things up.

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Javier PL avatar image Javier PL commented ·

First of all, I thank you very much for your response. I guess I'm asking about overly profound details and sometimes it's more curiosity than nothing else. However, the one about the performance drag and heavy shapes was really interesting to me.

In any case, your answer is absolutely enough, and as for now it's completely fine with the noticed issues because I was able to solve my problems.

I'll probably go through the next version of the software in the future and undertake the analysis. Also giving feedback here if possible!


Thanks again and regards,

Javi

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Cliff King avatar image Cliff King ♦ Javier PL commented ·

I just learned from the developers that it is NEVER a good idea to recycle flow items. It will ALWAYS be slower and use more memory in every case. It will eventually be removed, but there are some difficulties in removing it for backwards compatibility reasons.

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Javier PL avatar image Javier PL Cliff King ♦ commented ·

Seen and noted down.

Thanks for the info, @Cliff King

Javi

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