Untitled.skp (221.6 KB)
The “reverse faces” I did just to try, problem is now that I’ve no idea which faces need to be “reversed” and for “stray edges”, I don’t see what is “stray” about them, I just erased them and draw again with the line tool but it doesn’t seem to get me any further…
As I wrote, there should be no blue back faces visible from the outside of the object. Any face that shows blue needs to be reversed so its white front face is out.
The red circle in the screenshot I shared is surrounding a stray edge. Zoom in close and erase it. There’s another one near the same height in the vertical corner. There’s actually two edges at each of those locations.
Hi, thanks a lot, to find the "stray edges’ I zoomed in a selected them(“entities”) one by one and then redid them, I got my group! That’s 4 hours of pure frustation solved! Thanks again!
Good deal.
If you’re planning to do much of this kind of stuff you might find it helpful to get at least a SketchUp Go subscription so you get Solid Inspector. That said, with practice you should be able to identify and fix things that prevent your objects from being solids. With a little more practice you should develop a workflow that allows you to create solid objects without having to fix anything.
Are you planning to 3D print the objects you’re modeling?
FWIW, I would suggest you keep your models close to the origin.
30 seconds 
Dear David,
Thanks again for your help. I started with “sketchup” to make drawings of buildings of which I need to calculate the volume. This for a course “energy expert”, i.e. to examine houses/apartments how good (or bad) they are isolated. If I will start it professionally I will definitely go for a subscription as without the tool “solidifyer” it’s almost impossible to find the little “strays”.
Cheers!
Peter