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.
1 Like
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.
2 Likes
Oh god… You’re hero… thank you very much… <3
1 Like
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…
1 Like
I’m sorry, I’m newbie, I don’t know that… @_@
No problem…
Have a Happy New Year…
1 Like
I seem to have the same issue, but can’t find any hidden groups. What else could be the matter?
Terrain.skp (511.4 KB)
One small edge is getting in the way.
Might help to get rid of the stray edge off the near corner.,
What Box shows.
With that done slicer works quite nicely.
Oh great, thanks a LOT! So easy when you know what’s wrong. Did you just see it by chance or is there any way to search in the model to see what’s wrong?
Thank you very much! So frustrating when you can’t see what you’ve done wrong.
Considering both Dave an I answered within 4 minutes of your question the stray edge was pretty obvious to our eyes.
However, Solid Inspector is a great tool for finding errors.
Well, you are true heroes to a beginner like me!