My apologies in advance if this is not the right place to post this question, or if this would be a better question for the SketchUp community.
Long story short, I am trying to design a part in sketchup. A little clip that has a void down the center of it. This open section is approximately 1.25mm wide by 12mm long. Everything looks good in sketchup, and it passes all tests in S3D's checks in the repair tab (Not bad for a first-ever design, I like to think).
The problem comes in when I go from the prep stages in S3D to preparing for a print, Looking at the preview, that empty space is filled in, creating a solid piece. I have attached screenshots from S3D, I would attach the sketchup file but it looks like .skp is not allowed on here.
Are there certain dimension tolerances that S3D cannot handle or will ignore and therefore fill in, or am I missing something else altogether.