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Union two or more non-intersecting parts?

sgsg Member Posts: 3
Is there a way to union two or more parts which do not intersect?

This would be a nice feature for 'advanced' boolean operations (union of some parts, then intersection of the results...)

Best Answer


  • 3dcad3dcad Member, OS Professional, Mentor Posts: 2,447 PRO
    edited June 2015
    Why do you wan't to do that?

    If you think it in the real world, two pieces that do not connect to each other are often thought as two separate pieces rather than one.

    In assembly you can use 'Group' which makes two (or more) parts move together without needing to add other mates.
  • sgsg Member Posts: 3
    In CATIA the boolean functionality is often used for providing a structure.

    For example for a drill plate you could union all holes and openings in one part ('negative features'), then remove this part from the whole plate ('positive feature').

    Once the features are ordered under the parts on boolean operations, the tree would be more clearly arranged.
  • jakeramsleyjakeramsley Member, Moderator, Onshape Employees, Developers Posts: 622
    For me personally, I don't think union is the correct tool for this.  To me it is muddying the terms between unioning the parts and unioning the selection.  A different mechanism would make more sense to me that would allow for easy selection sets.
    Jake Ramsley

    Director of Quality Engineering & Release Manager              onshape.com
  • andrew_troupandrew_troup Member, Mentor Posts: 1,584 ✭✭✭✭
    edited June 2015
    I had the same thought as @jakeramsley ;
    but I didn't get it clear enough in my mind to put down.

    I wonder if it comes down to an (important) issue of conceptual purity: is boolean (as the software processes it) currently about adding and subtracting bodies, or is it about parts?

    I presume it is the former from the current behaviour: when you add together two bodies which do not touch, you inevitably get two bodies, in other words, no change to the status quo.

    If so, I can see that the functionality being asked for here would require a rethink and a rewrite of the code, so that the unit under consideration was changed from 'bodies' to 'parts'.

    I would be interested to hear from someone at Onshape whether doing this, to address one problem, might result in new problems (behavioural, not just conceptual) in other areas.
  • 3dcad3dcad Member, OS Professional, Mentor Posts: 2,447 PRO
    I'm that way simple person that I don't care if it's called boolean or something else. But I would like to see 'some feature' that I could use when for example patterning a drill to subtract material, 10x10 holes makes 100 drills = 100 parts, there should be a way to combine these into 1 part.

    Otherwise I think derived parts will do the trick IF patterning added part for above purpose just shows up as one feature and not multiplying part.

    But let's first see what hole wizard and derived parts bring before making changes to boolean feature.
  • IT_RobotiqIT_Robotiq Member Posts: 2 PRO
    Regarding of this subject, we have an engraving on a part and we want to put a different color on the engraving that on the part. To do this, I thought I could make new parts by thickening the faces of the engraving, then by modifying the appearances of these new parts. 
    The problem with it is that it creates a lot of new parts, wich we don't want to. So, we wanted to union these new parts that don't touch each other.
    Unfortunately, OnShape won't let me.
  • 3dcad3dcad Member, OS Professional, Mentor Posts: 2,447 PRO
    Coloring faces would be your solution. This is highly requested feature for long time and I'm sure Onshape is working hard to push that feature as soon as possible.
  • romeograhamromeograham Member Posts: 471 PRO
    You could connect the new parts with a solid feature that is entirely inside your engraved part (so you don't see it). Now you have only 2 parts: the Engraved part, and the thickened faces of the engraving. You can color the single "engraving" part for screen caps / drawings etc.

    Under the surface, the two bodies will be intersecting, but this is not a problem, because the "engraving" part is only an aid for visualization.

    you could do the same thing (if only it was June 2015 again): pattern your 100 drill bits, and extrude a simple rectangular body that joins them all together. Voila, you have a single "tool" body with 100 drill-shaped bits sticking out. Now your Boolean Subtract (to create 100 holes) is a simple, 2-body affair.

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