Selection of high number of faces for boundary

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anthony74
Posts: 3
Joined: Fri Dec 06, 2019 4:02 pm

Selection of high number of faces for boundary

Postby anthony74 » Sat Dec 07, 2019 10:01 am

Hi, I'm trying to select the faces of my model for assigning wall boundary first and mesh + refinement. I am using the "select all" option. Model is complex with a lot of faces (>10000) and Freecad freezes few seconds after clicking on the button and needs to be restarted. I have tried others models with lower number of faces and I have figured out "select all" is working up to around 500 faces max. It takes few seconds but ok. Above 500, same problem happens.

Any solution to overcome the problem to select all faces for complex model?

I am trying now to split my model in X sub-models of max 500 faces so I can select the boundary conditions of the full models without crashing FC.

Thanks in advance for the help!

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.16131 (Git)
Build type: Release
Branch: releases/FreeCAD-0-18
Hash: 3129ae4296e40ed20e7b3d460b86e6969acbe1c3
Python version: 3.6.6
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedStates (en_US)
herbk
Posts: 1698
Joined: Mon Nov 03, 2014 3:45 pm
Location: Windsbach, Bavarya (Germany)

Re: Selection of high number of faces for boundary

Postby herbk » Sat Dec 07, 2019 1:53 pm

Hi anthony,

could you give a few informations about your system to?

Spontaneously I would say: Not enough RAM, not enough cores and speed... ;)
Gruß Herbert
anthony74
Posts: 3
Joined: Fri Dec 06, 2019 4:02 pm

Re: Selection of high number of faces for boundary

Postby anthony74 » Sat Dec 07, 2019 6:23 pm

Hi Herbert, thank you for your reply.

My system: i7-4790 @ 3.60Hz RAM 16GB

Anthony
herbk
Posts: 1698
Joined: Mon Nov 03, 2014 3:45 pm
Location: Windsbach, Bavarya (Germany)

Re: Selection of high number of faces for boundary

Postby herbk » Sat Dec 07, 2019 7:57 pm

Hi Anthony,

looking at the number of your faces i would say "a raindrop at a hot stone" (german aphorism)... :lol:

Beginning 2019 i run in a similar problem. If you understand a bit german this thread may be helpful a bit. https://forum.freecadweb.org/viewtopic. ... &hilit=cfd

A more easy example as the model of this thread is my last simulation at a (ok only) Laptop with an Ryzen5 and 16GB Ram. A simple airfoil in a tunnel, 5mm base element size.
Creating the mesh needs about 1 minute, the solver which creats the output for Paraview needs more then 10 minutes to create the case.
Gruß Herbert
anthony74
Posts: 3
Joined: Fri Dec 06, 2019 4:02 pm

Re: Selection of high number of faces for boundary

Postby anthony74 » Tue Dec 10, 2019 7:57 pm

Hi, I was not expecting the meshing/simulation to be easy and quick but after several iterations and different configurations of models and meshing, I can see here a threshold. Above a certain number of faces first and later during the meshing, Freecad is unable to finish the job. Below, it is fine. So I managed to do a simulation with this constraint: I reduced faces and try to keep meshing parameters corrects and the simulation was fine. Meshing took 20minutes but solving was quite ok.

I am now trying to see how my computer and settings can help to pass the threshold. Between CPU, RAM or Graphic card, what do you think is the most important? I can double the RAM easily but not so sure about the CPU.

Anthony