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Should a Boolean Fail if solids/bodies are missing?

florianflorian Member, OS Professional Posts: 99 PRO

Currently when a boolean subtraction has missing tools there is no hint, that there are missing parts in the boolean (see below) this can lead to troubles, if you subtract internal geometry that does not change the outer appearance a lot. So my question: should the boolean fail gracefully?

It could regenerate what it can, but then turn red. Would that be compliant with other behavior in Onshape? If the user starts editing the boolean does he have to restore the missing solids? Currently you can confirm the feature with missing bodies.



  • philip_thomasphilip_thomas Member, Onshape Employees, Developers Posts: 1,059
    edited October 2017
    @Florian - this was very very intentional.

    In CAD today (meaning most products), if the end result of a boolean is anything OTHER than a single body, then the operation fails.
    This is a pain because if one window selects 3 pairs of touching objects (6 parts) and boolean union them, then the expected result is 3 parts (in most cad this fails).
    The Onshape solution was to implement 'true booleans'. If AuB results in 3 parts - great, If A-B = Null, that's fine too. If AnB = Null, that's fine too.
    This is a far more robust solution than any other offering. To your other point, if you applied a boolean (eg AuB) and the net change is zero, Onshape provides an (intentionally) non-intrusive notification. If an input body is missing, that too does not generate an error because at some future time, it may reappear - again, the benefit to the user is resiliency.

    I hope this clears up our intentions and the benefits :)
    Philip Thomas - Onshape
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