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Boolean Intersection of Surface Extrusions (Curved)

emil_4emil_4 Member Posts: 5
Dear Onshape Developers,

Any chance of adding capability of doing boolean intersection of surface extrusions (results in a curved line)?  Boolean intersections only seem to work with parts.


  • lougallolougallo Member, Moderator, Onshape Employees, Developers Posts: 2,000
    @Emil I have logged this.  It is a very common practice to do an intersection curve like this to generate complex paths for sweeps and other geometry.
    Lou Gallo / PD/UX - Support - Community / Onshape, Inc.
  • emil_4emil_4 Member Posts: 5
  • fastwayjimfastwayjim Member, OS Professional, Mentor Posts: 220 PRO
    Hi @LouGallo ! Can you add me to that ticket please? We were discussing this in another post (here). Thanks!
  • andrew_troupandrew_troup Member, Mentor Posts: 1,584 ✭✭✭✭✭
    edited April 2015

    also another highly desirable capability: Cut with surface

    ("extrude cut from surface" would be a workaround, once you get round to adding a "from" condition, as well as a "to" condition, to extrudes ... but it would require creating a sketch, and probably a plane)
  • abefeldmanabefeldman Member Posts: 166 ✭✭✭
    @Andrew_Troup and @FastwayJim - Added you both to the improvement.

    @Andrew_Troup, can you elaborate a bit more on your 'cut with surface' request?  While our surface generation tools aren't very mature yet, we do allow you to split parts using surfaces.  Is that similar to what you're asking for?

    Abe Feldman
    UX/PD/Community Support
  • andrew_troupandrew_troup Member, Mentor Posts: 1,584 ✭✭✭✭✭
    edited April 2015
    OK, I can split using my surface, and then delete one of the sub-parts. Thanks a bunch!

    That's a pretty satisfactory workaround. It might be even better (and eliminate the need for a "Cut with Surface" tool altogether) if I could choose which parts to keep, to simplify the feature tree. I wonder if there is merit in OnS automatically renaming features when a 'versatile' tool is used in different ways? So that "Split Part" might become "Cut Part" if only one component was kept, and "Split/Cut part" if not all components were kept.

    This might seem a lot of trouble to go to, but in the case of Split Part, there is currently no visual indication, when using rollback, that anything has happened. Perhaps new colours could be allocated to newly created parts?

    Solidworks went part way there with the "Offset Surface" tool; if you specified zero, the Title bar description would change to "Copy Surface" (but, perplexingly, the FM tree description did not!)

    Particularly if the OnS tree remains purely textual, it seems to me the default descriptions need to be enriched. At present I cannot tell from the tree whether Extrude 1 is a solid, or a surface, or a cut-extrude, or an intersection, or some combination.

    Personally my preference would be for that information to be captured with a combination of text and other cues: it's simply too slow and klunky to have to read each line in order to orient yourself to the tree, even before you start to extract meaning from it.
  • Eric_52Eric_52 Member Posts: 2
    Was the intersection sketch of two surfaces added as a feature?  It is one major thing holding me back from switching to onshape from solidworks.
  • michael_hwangmichael_hwang Member Posts: 2
    Was this ever added?  I'm halfway through my model and I need to make a curve like this, but now I'm stuck.  I thought this was trivial so I didn't check for this capability beforehand...
  • konstantin_shiriazdanovkonstantin_shiriazdanov Member Posts: 1,221 ✭✭✭✭✭
    @michael_hwang there is split comand that makes intersection edges, and composite curve feature that makes a wire body from the set of connected edges
  • owen_sparksowen_sparks Member, Developers Posts: 2,660 PRO
    And the projected curve...
    Business Systems and Configuration Controller
    HWM-Water Ltd
  • MBartlett21MBartlett21 Member, OS Professional, Developers Posts: 2,031 EDU
    Try this boolean feature:
    It takes parts, surfaces or faces as input.
    If you input two surfaces with intersection selected it will generate a curve
    mb - draughtsman - also FS author: View FeatureScripts
    IR for AS/NZS 1100
  • billy2billy2 Member, OS Professional, Mentor, Developers, User Group Leader Posts: 2,007 PRO
    You're tearing these surfaces and leaving the extensions up to some algorithm. Other than that, you can split'm. This gives you an edge (which is a curve) or you can delete one of the bodies (which is a trim). This isn't real obvious, could be better.

    We need good knit and unknit tools. If you have trimmed surfaces, you have to use enclose to knit which is way more than it should be.

    This said, it takes a little work, but you can get surfaces to work.

  • MBartlett21MBartlett21 Member, OS Professional, Developers Posts: 2,031 EDU
    My feature only calls opBoolean using definition.
    It sets allowSheets to true and eraseImprintedEdges to false for a surface intersection.
    It doesn't work if it should create two curves (see https://forum.onshape.com/discussion/9239/opboolean-on-surface-bodies)
    mb - draughtsman - also FS author: View FeatureScripts
    IR for AS/NZS 1100
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