the error is coming from the top edge of the vase. it is saying it's too thin. you can probably ignore it or fillet the edge to remove the sharpness.
val

Hi Lynno,
as val2 pointed out its the top edge.
I trimmed 0.1mm of the top to clean up and sliced it in Ideamaker no problem.
It would also slice without trimming after an auto repair is applied in ideamaker.
Cheers
Barry

Hi,

My theory is that your problem comes from your "Vase mode".

Your object is a full solid and plain vase.

Your software wants to do the same thing as a "Shell" operation.
Without the patterns, it's OK, I think. but with it, this mode could give you some problems.

My advice is to do a real vase with your revolution surface (unselect the cap ends checkbox), and do a Shell on it (or do a surface of revolution with a closed curve with inside and outside.
Next you add the patterns.

A theory to be verified...

I don't see a problem in Cura. Your pattern sticks out too far creating overhangs though, which will result in holes on vertical surfaces.

Thanks everyone for your help. Phiro, re Vase mode: I've created some complex surface patterns using other methods, and although these have made the object difficult to shell, vase mode in S3D has handled it well. I'll use all these thoughts to make something more interesting, and see how I go :)