There are lots of faces that aren’t really joined when exporting an STL file to a slicing program for 3D printing. Can you make sure Sketchup actually snaps the lines together properly and that models become solid without holes? Most Sketchup files have errors as the slicer programs say there are lots of errors with the files.
Got a sample model or two to share so we can see exactly the issue is?
Sure. I’ll make some files now.
Can you upload the actual SKP file?
I just got to work. I’ll upload a file as soon as I get back home.
Have you controlled the face normals? Some programs don’t show faces with wrong face direction.
Perhaps this will help with your trouble shooting.
I download a stl file from this Honda site http://www.autoblog.com/2014/01/30/honda-3d-printer-concept-cars-video/ , the low poly version.
Before using I check in NteFabb free version and it shows as printable, importing to SU 2014, the resulting skp file reports as solid. Here is the skp file link https://www.dropbox.com/s/pshl0mtt9wszbfo/honda_snx_lowpoly_stl%20_skp.skp?dl=0 . If I export the skp file as dea and then reimport the model does not show as solid and there are some non manifold faces, duplicate faces in the exported dae per mesh lab, file size is much smaller also.
There are so many faces trying to check normal by what su has available ( reverse faces) would be a pain?
1)_ Download Meshmixer (is free)
2)Repair Manual or Automatic…Very easy
3) Save in .OBJ or .STL
4)_ Use the program you use to print
I would suggest to find the reason for the problem and not to search a way to repair the model…