SLOW MODELING, check this! Load time went from 1:04 to :04

[freedman]

Been reading thru the OCC docs on their site and found something. The defaults for "Angular Deflection" were recommended to be 12-20. I looked at my model and they are set at 1.000. As far as I know I didn't do this. Here is what I know:

My project; I am ticked off and relieved at the same time. For weeks I have been sitting at my work station watching the clock tick by as FreeCAD crunches away processing little changes. I have probably wasted 100 hour watching the (no response) from Windows waiting for the program to finish. When I open the model I go get coffee or do something so I don't tear my hair out, I'm not sure I would have started another large project using this program. Sooo now, I changed the "Angular Deflection" setting on all my bodies to 28.5 and opening my model went from over a minute to probably less than 4 seconds, changes are now lightning fast.

The program; I did some searching and there are many posts that talk about "don't set this to 1.00" because it will take the model forever to process. I searched out one post where someone set it to zero and FreeCAD crashed, so the programming team set a default of a minimum of 1.00 so that wouldn't happen again, maybe we can revisit that fix.

Searching thru files: On my machine I have many files downloaded from users during a help section and found many different values for Angular Deflection, mostly 28.5 but I found a few at 6.00 and 1.00. I looked in my config file and it shows it 6.000, don't know why.

I wonder if there is a program problem where it gets confused opening a model (or something) and sets the Angular Deflection to the default value.

If a few folks could post here if there Angular Deflection values are other than 28.5, that would be great!

Thanks

OS: Windows 7
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.15780 (Git)
Build type: Release
Branch: master
Hash: f94e76c1116ec3b818961ff65131b3d86fa5b95e
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: English/UnitedStates (en_US)

[cox]

28.5 here

OS: "Manjaro Linux"
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.13541 (Git) AppImage
Build type: None
Branch: releases/FreeCAD-0-17
Hash: 9948ee4f1570df9216862a79705afb367b2c6ffb
Python version: 2.7.6
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: Norwegian/Norway (nb_NO)

[kisolre]

Where is this setting located?

[chrisb]

Part Design -> Shape View. It is a preset value which is copied into each document.

[Roy_043]

It is a bit confusing that every Body also has its own Angular Deflection property that gets reset when you change this setting in the Preferences. Is this intended behavior?

EDIT: Or maybe the body property is not really updated? It does not seem to trigger a change to the document.

[GeneFC]

It is a bit confusing that every Body also has its own Angular Deflection property that gets reset when you change this setting in the Preferences. Is this intended behavior?

EDIT: Or maybe the body property is not really updated? It does not seem to trigger a change to the document.

There is only one value of Angular Deflection property saved when the FCStd file is saved. Inside the FCStd document each body has an entry for the Angular Deflection, but it is the same value throughout. That value is whatever it was in the Preferences when the document was saved. I suppose you could edit the FCStd file to change the Angular Deflection, but I do not know why you would do so.

The OP had a real issue with the AD somehow changed to an inconvenient value. Otherwise, there is nothing very useful here. I have never seen a use case for changing the AD to anything other than the default 28.5 degrees, which is approximately 0.5 radian.

If you know of some reason to change this value it would be interesting to know what that is.

OCC has a very readable and informative wiki item about this parameter.

https://www.opencascade.com/doc/occt-7. ... odalg_11_2

Gene

[bejant]

If you know of some reason to change this value it would be interesting to know what that is.

Sometimes the geometry in the 3D view appears deformed:


and decreasing the value can remedy that. The image is from this forum topic, but there are several more topics from years ago (my forum search didn't find them): https://forum.freecadweb.org/download/file.php?id=33662

Thanks for the OCC link!

Edit: Here's another image:


from this post: https://forum.freecadweb.org/viewtopic. ... 30#p241676

Searching for "tessellation" gave better results.

[freedman]

The value is in Properties-View tab. It displays in Bodies and Sketches. It sounds like maybe it's just something here, maybe I changed it long ago and it is messing up my files. I wrote a couple macros to change them.
I found many posts, like bejant said; If you need your non-straight lines smooth then this value can be deceased, but speed is the price.

NOTE: It does make a big difference on your STL export. Using 28.5, I can see the flats on a radius in the slicer, using 1.00, it's smooth as can be. Maybe the approach is to do the entire design at 28.5 and then set it to 1.00 and recompute (wait for it), then export to STL. Then set it back to 28.5 for more design changes. Maybe this should be automatic during an export, prompt the user for a resolution. A simple STL file changed from 11KB to 114KB depending on this setting.

[Roy_043]

but it is the same value throughout.

I do not know to what extent this is important, but in my test two bodies in the same document can have different values. And if it is really a global setting (or a by document setting?) why is it listed among the view properties of each body? Seems illogical.

[freedman]

It's not a global setting, my slow updating model had all kinds of different settings, some 28.5, some 6.00 and some were 1.00. I have been sending files out for SLA and the returned parts look great. Maybe they wouldn't have looked so good if I used 28.5. Going to need to do some testing now, I'm not sure what to do.