Boolean union makes open polysurface dissapear? flipping doesnt work

Rhino Rhino for Windows
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1

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ive checked other forum posts where people had the same problem and it said its usually the direction of the open surface. ive tried flipping it, but it keeps dissappearing. it dissappears regardless of the direction its facing. help appreciated.

help needed boolean union body.3dm (4.0 MB)

2

Hi,

Is your intention to create a hollow space at the bottom of the object? If so, you should cap the cutter piece so it is solid and difference it from the main object.

Here’s a clipped view of the result:

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If that isn’t your intent then please clarify what outcome you do want.

HTH
Jeremy

3

hi, yes that was my intention. i dont know how i didnt think of that first, thanks!

4

Bear in mind that internal voids have to either have a passage to the outside world (as this one seemingly does) or need some special handling using the nonmanifoldmerge command. The latter approach can cause downstream modelling problems so it is best left to the last moment of the modelling process.