Delete faces of imported step geometry

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simplemind
Posts: 8
Joined: Fri May 10, 2019 1:43 pm

Re: Delete faces of imported step geometry

Postby simplemind » Fri May 10, 2019 10:02 pm

Jim,

OK, I've attached the Plastic Duct with thin vents.

Image-1 shows the bad blend and the 2 blend paths to remove.

Image-2 shows the clean up function results in another CAD system.

This is just 1 localized area on this part. It's HUGE. I'm talking about defeaturing a few hundred blend paths in just this model alone.

I've looked at this help page, but the sub-pages are not ready yet. https://www.freecadweb.org/wiki/Defeaturing_Workbench

Is there a way to pick a pocket face blend like the bad one in the image, then use one of the defeature buttons and the pocket face blend goes away while allowing the other wall/contours re-join all in one action? That's how the other CAD systems do this. I'm not sure exactly how to do this in the DeFeaturing tool. I've poked on a few buttons with trial/error but have not found the right function or combination yet.

I must say, going from 16 to 17 to 18, this package is beginning to look and feel like a powerful CAD system. :)
Attachments
Plast-Duct-02-after.JPG
After - Done in another CAD system from a helping buddy. But the back and forth interaction takes time vs. being able to do this in FreeCAD
Plast-Duct-02-after.JPG (44.46 KiB) Viewed 173 times
Plast-Duct-01-before.JPG
Before - as-is STEP file. CFD software can not manage these blends nor the bad blend conical surface
Plast-Duct-01-before.JPG (56.52 KiB) Viewed 173 times
Plastic-Duct-with-thin-vents.zip
Plastic Duct - to remove blends with no voids in 3D model
(741.93 KiB) Downloaded 10 times
simplemind
Posts: 8
Joined: Fri May 10, 2019 1:43 pm

Re: Delete faces of imported step geometry

Postby simplemind » Mon May 13, 2019 12:56 pm

Anyone have a solution? I'm struggling trying to understand this DEFEATURING add-on.

Anyone using the NEW add-on of DEFEATURING yet ???

It's a major help for making CFD models taking out the tiny faces and tiny blends that would have no effect on the overall results. Saves on meshing time, saves on computing time and avoids troubles trying to mesh.
jmaustpc
Posts: 9282
Joined: Tue Jul 26, 2011 6:28 am
Location: Australia

Re: Delete faces of imported step geometry

Postby jmaustpc » Mon May 13, 2019 1:35 pm

simplemind wrote:
Mon May 13, 2019 12:56 pm
Anyone have a solution? I'm struggling trying to understand this DEFEATURING add-on.

Anyone using the NEW add-on of DEFEATURING yet ???

It's a major help for making CFD models taking out the tiny faces and tiny blends that would have no effect on the overall results. Saves on meshing time, saves on computing time and avoids troubles trying to mesh.
Sorry, I have not ever used it personally so I don't know much about it. Off the top of my head, easyw-fc is the developer of the workbench.

This quote will notify him of your request.
easyw-fc wrote:
easyw-fc could you help simplemind in this matter? Am I right about this being your work? :)

Jim
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easyw-fc
Posts: 2449
Joined: Thu Jul 09, 2015 9:34 am

Re: Delete faces of imported step geometry

Postby easyw-fc » Mon May 13, 2019 2:10 pm

@simplemind, please have a look at:
https://www.freecadweb.org/wiki/Part_Defeaturing
https://www.freecadweb.org/wiki/Defeaturing_Workbench

as from a previous @NormandC post:
NormandC wrote:
Wed Dec 12, 2018 2:41 am
There is one essential rule: from the selection of faces to delete, it must be possible to rebuild a solid. Take a simple cube for example: you cannot delete any face because the defeaturing tool couldn't rebuild a solid. Now if your cube has a hole in it, then you can select the inner cylindrical face and the hole will be "plugged in".
phpBB [video]


few tips here:
https://forum.freecadweb.org/viewtopic. ... =9&t=29506
https://forum.freecadweb.org/viewtopic. ... 23#p241870
simplemind
Posts: 8
Joined: Fri May 10, 2019 1:43 pm

Re: Delete faces of imported step geometry

Postby simplemind » Tue May 14, 2019 10:47 pm

easyw-fc,

Is it possible for you to grab my previous CAD STEP file attached to the other posting. Then see if you can defeature the same as the images I had placed in the posting. I'm trying this without have any results.

I've tried both the 'parametric refine' and the regular 'refine'. Then add a face from the solid. Then per the video, choose the icon for 'parametric defeature'. The entire solid disappears. :roll:

Have I missed something?
simplemind
Posts: 8
Joined: Fri May 10, 2019 1:43 pm

Re: Delete faces of imported step geometry

Postby simplemind » Wed May 15, 2019 12:55 pm

easyw-fc , WOW. I had loaded a more simple part that is the size of a coffee mug. Your tools work wonderfully on this part from a STEP file. I'm not sure if FreeCAD has limitations on the much larger part that I really need to defeature. A former co-worker now at another company can do this in a high level CAD system like UG-NX and SolidWorks. BUT, I don't want to take his work hours doing my stuff. There are the STEP file translation issues to tend with as well. Sure, STEP is far better than IGES (I-guess), but it has some quirks too.

Your Defeatureing set of tools are extremely useful. It is a strong asset to FreeCAD. My applause to you for the ability to program and knowing how to keep a simple user interface. Thank you!

8-)
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easyw-fc
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Re: Delete faces of imported step geometry

Postby easyw-fc » Sat May 18, 2019 2:23 pm

simplemind wrote:
Wed May 15, 2019 12:55 pm
easyw-fc , WOW. I had loaded a more simple part that is the size of a coffee mug. Your tools work wonderfully on this part from a STEP file.
Thanks, FreeCAD is a very powerful and flexible sw... it has been created very well since the beginning based on OpenCascade, Qt and Coin3D, and it has grown very powerful during the years.
This is because of the main developers, package maintainers and also because of a great user base community which has also developed many useful workbenches.
Defeaturing WB is here because of the help of @Chris_G who included the OCC C++ code into FreeCAD main stream. I managed to add some useful functions in a single WB, to help in handling STEP models in my workflow.
simplemind wrote:
Wed May 15, 2019 12:55 pm
I'm not sure if FreeCAD has limitations on the much larger part that I really need to defeature. A former co-worker now at another company can do this in a high level CAD system like UG-NX and SolidWorks. BUT, I don't want to take his work hours doing my stuff.
Defeaturing is a quite difficult process... you can get some tips on how to chose the faces to defeat a shape at OCC 3D model defeaturing page
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removing-blend.png
removing-blend.png (239.34 KiB) Viewed 48 times
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simplemind wrote:
Wed May 15, 2019 12:55 pm
There are the STEP file translation issues to tend with as well. Sure, STEP is far better than IGES (I-guess), but it has some quirks too.
IGES is an old standard, not really updated since 1996
It’s Time to Get Over IGES: GrabCAD
simplemind wrote:
Wed May 15, 2019 12:55 pm
Your Defeatureing set of tools are extremely useful. It is a strong asset to FreeCAD. My applause to you for the ability to program and knowing how to keep a simple user interface. Thank you!

8-)
STEP is a very important asset for FreeCAD because it allows FC users to exchange models with other proprietary CADs.
A strong STEP import/export and defeature library/tool-set is giving FreeCAD a good reputation in CAD interoperability ad a chance to become a widely used mechanical CAD.

Thanks again, I'm glad to hear this positive feedback :D