Flashprint errors

Continuing the discussion from Problem With Solid Object:

Hi I am looking for help please, hope I am in the right place. I have just purchaced a 3D printer, am in no way new to SketchUp. I thought I was all over the correct sides facing (with solid inspector), I printed a simple model from SketchUp previously which worked fine. So now I have my first project which is have attached. When taken it into Flash print the program finds errors, prompts me to fix them and changes the issue! . this results in strange walls in places I don’t want them. (Screen shot)
I have re drawn all faces incase there was extra lines or double faces. I have looked at all forum posts to get an idea, but just not sure where I am going wrong.
Fan shroud.skp (327.2 KB)

Note; I need to make the project in 3 pieces due to the print size. Out of interest I imported the file before dividing it, and I had no issues

Much Appreciated

I did a test where I exported as STL, then imported that into a new SketchUp file. Solid Inspector was then not happy, and the groups were not solid. I found that scaling up the outside pieces got them to a point where they still had a volume after importing, but I haven’t managed that with the middle piece yet.

I think that if SketchUp doesn’t see the STL exports as solid, the printing software might not too. i.materialise may be coping better with the problem, and Cura also only shows a problem where there are areas that will need supports.

While I can’t open the file as I didn’t move to SU20 (for reasons to lengthy to go into) and not being a code expert, I can say that I find the triangulation of objects converted to .stl a constant irritation. It is normal to find a file to be (sometimes badly) messed up when imported back into SU. A total guess and somewhat bizarre explanation, but It seems to be about relocation of vertices to suit something in the .stl formatting. Also, I find that different slicing software will produce different results. One thing to look for is hidden geometry which sometimes is missed in SU but can do weird things in the slicer. Generally, if SU see the model as a solid so to will a slicer.

When I did my reimporting STL test, this was one of the problem cases, there are some very small face areas. Also, if I carefully select that edge area it shows as being two entities occupying the same space.