Face numbering issue

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paul18
Posts: 174
Joined: Sat Jul 19, 2014 7:44 pm
Location: France

Face numbering issue

Postby paul18 » Wed Oct 21, 2015 3:15 pm

Dear All,

I've been noticing that some basic changes in the CAD model i.e. if I simply change a radius value without adding any new edge nor surface, the surface number has been change as well

In the current case, I simply modified 2 radius values, leading to the complete assembly failure :cry:

Hope it'll help for the future improvments

Paul
Attachments
issue.png
issue.png (84.28 KiB) Viewed 1094 times
spider_FreeCAD_view3.png
spider_FreeCAD_view3.png (100.99 KiB) Viewed 1094 times
spider_FreeCAD_view2.png
spider_FreeCAD_view2.png (80.92 KiB) Viewed 1094 times
spider_FreeCAD_view1.png
spider_FreeCAD_view1.png (102.96 KiB) Viewed 1094 times
triplus
Posts: 8878
Joined: Mon Dec 12, 2011 4:45 pm

Re: Face numbering issue

Postby triplus » Wed Oct 21, 2015 3:32 pm

Nice model.
if I simply change a radius value without adding any new edge nor surface, the surface number has been change as well
In theory and as i understand it that shouldn't happen. But then again it's hard to say what exactly happened. What lead you to believe it was the face re-numbering that occurred and not something else is the cause? And does re-defining of the suspected assembly constraint fix it?
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quick61
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Location: u.S.A.

Re: Face numbering issue

Postby quick61 » Wed Oct 21, 2015 5:40 pm

Could you post the file of the part in question?

+1 on the nice model. :)

Mark
This post made with 0.0% Micro$oft products - GOT LINUX?
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DeepSOIC
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Location: Saint-Petersburg, Russia

Re: Face numbering issue

Postby DeepSOIC » Wed Oct 21, 2015 8:21 pm

I had this stuff happen, too, even in some very simple situations. I'm afraid the only thing that is going to resolve it is the topological naming, most of us are dreaming of.

The simple case was a sketch with two or maybe three separate contours, padded, that I used as a master sketch/pad to make several sub-sketches to be extruded afterwards.

Now that I use my custom branch where links to external geometry are unlimited, I have almost forgotten about the issue. Edge numbering in a sketch is relatively stable, and renumberings are predictable (I know exactly what I can do to a sketch that was used elsewhere, and what will cause a renumbering and re-linking).
paul18
Posts: 174
Joined: Sat Jul 19, 2014 7:44 pm
Location: France

Re: Face numbering issue

Postby paul18 » Wed Oct 21, 2015 9:48 pm

I noticed differences in the behaviour between the Windows release (for the face renumbering issue) and Linux one (under Ubuntu); I cannot say why but Freecad seems to be more stable under linux

I'll post tomorrow file having the trouble

NB: For the project of the spider, I'm not the original designer; you can have a look at the address bellow for the information's
http://www.instructables.com/id/DIY-Spi ... /?ALLSTEPS

But regarding this amazing project, I decided to re-modelle one (as some members of my fablab now :lol: ).

All the files will be shared soon in our website

Paul
paul18
Posts: 174
Joined: Sat Jul 19, 2014 7:44 pm
Location: France

Re: Face numbering issue

Postby paul18 » Thu Oct 22, 2015 8:19 am

Hi

here is the file I was spoken about; a change in the geometry led to assembly constraints issues due to the face renembering.

I tried this morning to reproduce the problem under a Windows release but I failed (why ?)

Paul
Attachments
femur_rebuild.fcstd
(201.04 KiB) Downloaded 16 times
Last edited by paul18 on Thu Oct 22, 2015 2:43 pm, edited 1 time in total.
jmaustpc
Posts: 9587
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Location: Australia

Re: Face numbering issue

Postby jmaustpc » Thu Oct 22, 2015 2:07 pm

paul18 wrote: I cannot say why but Freecad seems to be more stable under linux
That is quite likely, the opposite is also possible. On Ubuntu FreeCAD itself is usually a more advanced version however even if both have the 0.15 release versions of FreeCAD, from memory the Ubuntu versions was compiled against some newer versions of various Libs.

If you go to the Part or PartDesign workbench first and then got to the help menu ...about FreeCAD...copy to clipboard and past here from both Ubuntu and Win, you will likely see what I mean. For example the OCC/OCE version on Ubuntu, from memory, is more recent than the version used in Windows for that version.
jmaustpc
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Location: Australia

Re: Face numbering issue

Postby jmaustpc » Thu Oct 22, 2015 2:10 pm

the numbering of geometry is done by the OCC/OCE CAD kernel, so a difference in behaviour sounds conceivable.
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quick61
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Re: Face numbering issue

Postby quick61 » Thu Oct 22, 2015 2:24 pm

Having a look at your model, the first thing I noticed is that you have Fillets "inside" your history. This is usually not considered best practice. Fillets should be left to the end of the model's history. In this case, senes there is no external geometry built on the Fillets themselves, this may or may not be the source of your problem. As a test, give the attached model a try. This is how I would model the part. See if it is more stable and better behaved than your version is and let us know. :)
FemurAlt.fcstd
(112.19 KiB) Downloaded 19 times
Mark

OS: Kybuntu 14.04.3 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.5794 (Git)
Build type: Release
Branch: master
Hash: e7a3dc48e834591e5553d5c37ef997e70d177a94
Python version: 2.7.6
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17-dev
This post made with 0.0% Micro$oft products - GOT LINUX?
paul18
Posts: 174
Joined: Sat Jul 19, 2014 7:44 pm
Location: France

Re: Face numbering issue

Postby paul18 » Thu Oct 22, 2015 2:57 pm

@quick61

Interesting way of processing; however I've ever learnt that chamber/fillets must not be drawn in the sketch and at the latest stage (especially if one want to remove it) - but I did not respected it at all ... how lazy I am ! :oops: