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Sheet metal "Tangent Joint"?

eric_pestyeric_pesty Member Posts: 1,490 PRO
Ran into this today when converting an imported model to sheet metal and bends would not show up on the drawing. It turns out there were no bends defined as it was created by picking one face and using "tangent propagation", which picked all the of the relevant and generated a flat pattern...

However because the bend list was empty there were no "bends" defined. This was pretty confusing as there was a flat view of the part and "flat pattern" available to put on a drawing. The original bends (cylindrical faces) of the imported model had been converted as separate faces with "tangent joints" to the flat ones, I did not know that was possible and didn't notice (when converting a solid with sharp corners it's obvious you have to pick the bends as it will leave the individual faces disconnected if you don't!

After realizing what happened and populating the "bends" section of the sheet metal feature everything was ok...

However this left me wondering why this is even an option, what is it for? Anyone have some wisdom on how/why/when you would use this feature (cylindrical sheet metal faces not specified as "bends")?




  • S1monS1mon Member Posts: 2,359 PRO
    I found this really confusing working with imported sheetmetal as well. I'm really not sure what the point of the "other joints" section is, unless this will eventually be where they handle non-round bends (lofts, or spline profiles).
  • MBartlett21MBartlett21 Member, OS Professional, Developers Posts: 2,034 EDU

    The reason this is a separate selection would be so that it can use a different k factor for the rolled sections. It also doesn't require a flat face either side of the cylinder.
    mb - draftsman - also FS author: View FeatureScripts
    IR for AS/NZS 1100
  • eric_pestyeric_pesty Member Posts: 1,490 PRO
    Hmmm, not sure how I would assign a different K-factor since it's created all in one sheet metal feature.
    I do see how not needing a "flat" flange on end makes it different than a bend (if a bend is defined as a transition between two flat faces).
    I guess it paves the way to non cylindrical faces in the future (I did try to see if it would work on a conic section but it doesn't at this time...)
  • MBartlett21MBartlett21 Member, OS Professional, Developers Posts: 2,034 EDU
    edited February 2022

    I guess what I meant to say was that you can choose to not select the faces and they will come in as rolled sections, which have a different k factor.


    Under the other joints section in the table, rip joints are also shown, and you can make the rip go one way or the other as a butt joint.
    mb - draftsman - also FS author: View FeatureScripts
    IR for AS/NZS 1100
  • lanalana Onshape Employees Posts: 693
    A Tangent joint can be changed to Rip using that table. In some situations it is necessary to be able to unfold the shape.
  • eric_pestyeric_pesty Member Posts: 1,490 PRO
    Thanks for the answer, I haven't run into a scenario where I have needed to do that yet but it's good to know!
  • william_holden959william_holden959 Member Posts: 32 ✭✭
    I am running into this while creating a sheet metal part by extruding an open sketch. The flat pattern looks good, but I have 4 "joints" that define where the bends start and end, but no "bends" in the bend table. So, it does not show the bends in a dxf file. Is there a way to get the bends in there? I do not want to draw this part by "thickening" a closed sketch. Any help would be appreciated. Thanks!
  • lanalana Onshape Employees Posts: 693
    It sounds like you've sketched arcs where you wanted to have bends. There is no need to do that. Sketch poliline and the resulting extruded model  will have bends at every vertex. 
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