I use Sandbox to make object and then I use Slicer5. But I got massage “Select object is not manifold solid”, I tried to find the lost face or something wrong but I found nothing, I tried to scale 100/1 but that’s useless… help me please… 
Untitled000000.skp (2.3 MB)
Share the .skp file so we can see what you are working with. Give us some way to help you.
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You’ve got a hidden group nested inside the top level group. Here I’ve moved it down to make it visible.
Get rid of it and your group will be consider solid.
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Oh god… You’re hero… thank you very much… <3
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May I also comment…
Why not post in the Slicer5’s thread at SketchUcation ?
[Where you downloaded it from…]
I would be more likely to see it there - but luckily @DaveR saved the day…
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I’m sorry, I’m newbie, I don’t know that… @_@
No problem…
Have a Happy New Year…
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