Sheet Metal bending

Post here for help on using FreeCAD's graphical user interface (GUI).
User avatar
NormandC
Posts: 18158
Joined: Sat Feb 06, 2010 9:52 pm
Location: Québec, Canada

Re: Sheet Metal bending

Postby NormandC » Sun May 06, 2018 9:36 pm

I think there are two separate issues :

  • FreeCAD has an underlying weakness regarding internal topological identification. Basically, vertices, edges and faces are assigned ID numbers randomly. When you change a property, the object is recomputed, and if the number of faces changes, then the previously existing faces see their ID change. This is why you see unexpected results when you change the gap properties of BendRight. The following bends are not aware that the ID of the face to which they were applied has changed. So they try to apply themselves to totally different faces. (Currently, two FreeCAD developers are working on solutions to address that, but it will take time before the solutions are implemented in FreeCAD).
  • The Sheet Metal workbench add-on does not provide a way to reassign a bend to a different face, which would allow you to repair the model. This could be a feature request to https://github.com/shaise/FreeCAD_SheetMetal/issues
Last edited by NormandC on Sun May 06, 2018 10:56 pm, edited 1 time in total.
User avatar
NormandC
Posts: 18158
Joined: Sat Feb 06, 2010 9:52 pm
Location: Québec, Canada

Re: Sheet Metal bending

Postby NormandC » Sun May 06, 2018 10:16 pm

NormandC wrote:
Sun May 06, 2018 9:36 pm
This could be a feature request
Done: [FR] Allow editing the source face for Bend or Extend feature #32
jaisejames
Posts: 268
Joined: Sat Sep 24, 2016 6:51 am

Re: Sheet Metal bending

Postby jaisejames » Mon May 07, 2018 4:53 am

Pls refer last post. I modified SheetMetalCmd.py to do some editing capabilities for problem due adding or removing gaps. But It will not work in Part design since setedit() not supported in partdesign.
https://forum.freecadweb.org/viewtopic. ... 1&start=10
User avatar
NormandC
Posts: 18158
Joined: Sat Feb 06, 2010 9:52 pm
Location: Québec, Canada

Re: Sheet Metal bending

Postby NormandC » Mon May 07, 2018 5:02 am

Thanks for the info, but surely there must be a way to make this functionality compatible with PartDesign using some other mechanism? After all, PartDesign features can be edited.

Personally I have no interest in using Sheet Metal outside of the PartDesign workbench. It has got way too many advantages over the Part workbench.
Lars
Posts: 9
Joined: Sat May 05, 2018 10:39 am

Re: Sheet Metal bending

Postby Lars » Mon May 07, 2018 8:17 am

NormandC wrote:
Sun May 06, 2018 9:36 pm
I think there are two separate issues :

  • FreeCAD has an underlying weakness regarding internal topological identification. Basically, vertices, edges and faces are assigned ID numbers randomly. When you change a property, the object is recomputed, and if the number of faces changes, then the previously existing faces see their ID change. This is why you see unexpected results when you change the gap properties of BendRight. The following bends are not aware that the ID of the face to which they were applied has changed. So they try to apply themselves to totally different faces. (Currently, two FreeCAD developers are working on solutions to address that, but it will take time before the solutions are implemented in FreeCAD).
  • The Sheet Metal workbench add-on does not provide a way to reassign a bend to a different face, which would allow you to repair the model. This could be a feature request to https://github.com/shaise/FreeCAD_SheetMetal/issues
Good morning all,
Thank you for your fulfilling response to this issue for modifing and editing bends designed with the sheet metal workbench.
If I understand correctly, bends are currently not editable nor in the 1) part workbench or 2) part design workbench?

In addition, the sheet metal workbench unfold functionality is sensitive to the way cuts are implemented in bends. Somehow, the unfold feature is not working with cuts made with the part workhench, see example here which fails to unfold (https://rushfiles.one/client/publiclink ... zPtZF46QMV
). suggestions for introducing cuts are very welcome.

BR
Lars
Best regards

Lars
User avatar
meme2704
Posts: 2547
Joined: Sat Apr 01, 2017 2:47 pm
Location: Vosges

Re: Sheet Metal bending

Postby meme2704 » Mon May 07, 2018 8:46 am

Rather than to post your drawing on a site, post it directly as attachments
User avatar
meme2704
Posts: 2547
Joined: Sat Apr 01, 2017 2:47 pm
Location: Vosges

Re: Sheet Metal bending

Postby meme2704 » Mon May 07, 2018 10:47 am

How to attach i n post
Attachments
attach.JPG
attach.JPG (80.82 KiB) Viewed 91 times