Deflection in Faces

Post here for help on using FreeCAD's graphical user interface (GUI).
Forum rules
and Helpful information
IMPORTANT: Please click here and read this first, before asking for help

Also, be nice to others! Read the FreeCAD code of conduct!
user1234
Veteran
Posts: 3478
Joined: Mon Jul 11, 2016 5:08 pm

Re: Deflection in Faces

Post by user1234 »

Does not matter if SSD, except you run out of RAM and swap in the SSD, which will ruin it. ARM Processor? Compile it yourself? Tesselation settings?

Have you singularities in your models? This is was also meshing do not like. I made a defect model with singularities.
0.png
0.png (13.63 KiB) Viewed 395 times
- with 0.1% and 1° tessellation --> 20min --> =+ 3.3GByte RAM
- with 1% and 1° --> 10seconds --> RAM increase not noticeable

Without singularities errors:

- with 0.1% and 1° --> 2min --> =+1.5GByte
- with 1% and 1° --> 1 second --> RAM increase not noticeable

Just try to set the tessellation unnecessary rough to test and reduce the issues possibilities. For example here:
1.png
1.png (80.26 KiB) Viewed 395 times
and here
2.png
2.png (50.77 KiB) Viewed 395 times
. Just said, it is only a visibility settings, no geometry.

Greetings
user1234
User avatar
adrianinsaval
Veteran
Posts: 5544
Joined: Thu Apr 05, 2018 5:15 pm

Re: Deflection in Faces

Post by adrianinsaval »

user1234 wrote: Wed Jan 19, 2022 12:56 pm Does not matter if SSD
hhmm I would expect file load to be faster with an SSD, tessellation not necessarily. Are the shapes tessellated at file load? I thought the tessellated shape was also stored in the file.
MRx
Posts: 319
Joined: Wed Jul 08, 2020 5:59 am
Location: Tainan / Taiwan

Re: Deflection in Faces

Post by MRx »

the deviation settings are all okay (0.8% / 28.5°), the time it takes is usually opencascade loading time. I have crosschecked the loading time via C++ API back then.
BREP structures can be blown up from time to time, downgrading / upgrading the object in the draft workbench can separate dependencies which cause some heavy calculations it seems.
I do not know the details about the BREP file format, I did not have a look at that.
user1234
Veteran
Posts: 3478
Joined: Mon Jul 11, 2016 5:08 pm

Re: Deflection in Faces

Post by user1234 »

adrianinsaval wrote: Wed Jan 19, 2022 3:56 pm I thought the tessellated shape was also stored in the file.
No. then the files would be one or two magnitude bigger.


MRx wrote: Wed Jan 19, 2022 4:00 pm0.8% / 28.5°
That is for an macbook (laptop) too fine. I would set it to at least to 2%/10°. That sound too much, but in fact it is not that bad as it sounds and the visual difference it not that much. But the calculating speed increases extreme. The calculating time increases with the fineness approximately with between 2nd and 3rd potency (rough estimate, depend on the geometry).

I have set it on my workstation 5% and 10°. I only see that on freeform surfaces. And if i want it finer, then i set it in the properties per part finer. Then i also can quickly see, if it has an impact in the calculating time.

In commercial CADs, it is also often pretty rough set. Mostly around 2% and 15° or more (if you can set it, this is not always the case). But often there runs a visual graphic filter over it and then it looks shinier and the edges of the mesh are not that noticeable, only when you now them and look a little bit more accurate as normal.

Greetings
user1234
Post Reply